Prevención Cuaternaria: Pandemix y narcolepsia


¿Por qué una vacuna contra la gripe pandémica puede causar narcolepsia? La pandemia de gripe H1N1 2009 dejó un legado preocupante en Europa: Más de 1.300 personas que recibieron una vacuna para prevenir la gripe desarrollaron narcolepsia, una enfermedad incurable y debilitante que causa gran somnolencia diurna, a veces acompañada por una debilidad muscular repentina en respuesta a emociones fuertes tales como la risa o la ira. El fabricante, GlaxoSmithKline (GSK), ha reconocido el vínculo, y algunos pacientes y sus familias ya han recibido compensaciones. Pero no esta claro cómo la vacuna puede haber desencadenado la condición. En un artículo en la revista Science Translational Medicine (STM) esta semana, los investigadores ofrecen una posible explicación. Muestran que la vacuna, llamada Pandemrix, desencadena anticuerpos que también pueden unirse a un receptor en las células cerebrales que ayudan a regular la somnolencia. El trabajo sugiere que Pandemrix, que fue administrada a más de 30 millones de europeos, desencadenó una reacción autoinmune que condujo a la narcolepsia en algunas personas que tenían un riesgo genético. http://owl.li/P3Gxt

El cáncer- los gorriones, los osos y las tortugas


By: Alberto Velazquez. TEDxUBA
Published on Dec 22, 2013

In the spirit of ideas worth spreading, TEDx is a program of local, self-organized events that bring people together to share a TED-like experience. At a TEDx event, TEDTalks video and live speakers combine to spark deep discussion and connection in a small group. These local, self-organized events are branded TEDx, where x = independently organized TED event. The TED Conference provides general guidance for the TEDx program, but individual TEDx events are self-organized.* (*Subject to certain rules and regulations).

Antigeno Prostatico Especifico: inutil para el cribado de cancer de prostata


Todavia desconozco en que idioma hay que escribir esto, pero por enesima  vez sale otro articulo que dice que la PSA,  no tiene ninguna utilidad en el cribado de cáncer de próstata y que sólo sirve para el seguimiento de pacientes con Cáncer de prostata. El tema es simple. Se trata de una prueba inespecifica, y el famoso antigeno es volumen-dependiente del tamaño de la prostata. Por ende, en la natural evolucion que tenemos los hombres la prostata se agranda con la edad. Por tanto, ningun valor sirve para diferenciar si ese agrandamiento se  debió a la hipertrofia prostática benigna, que también es muy común luego de los 65 años. Por otro lado, un viejo anatomista,  Testut, ya escribia en su tratado que data del año 1900, que en sus autopsias encontraba un 100% de cáncer de prostata en hombres  mayores de 80 años. En otras palabras, y aunque los urólogos se empeñen en poner al cancer de próstata como un grave problema de salud, colocandolo entre las primeras causas de muerte, la realidad indica, que nos morimos más con cáncer de próstata que por el cáncer mismo. Por ende es un buen marcador de la evolución del cáncer pero no tiene ninguna utilidad, escrito en Inglés (también ha sido escrito en castellano, catalán, portugues, francés, ruso, y seguramente en esperanto) por el  British Medical Journal.
Por ende tendremos que seguir lidiando con los expertos que aparecen en la prensa de todo el mundo, e intentan convencer a la gente de hacerse estos estudios desde los 50 años.

Utilizando una cohorte grande Seuca relacionada con un registro nacional de cáncer, los investigadores compararon los valores iniciales de PSA de aquellos que desarrollaron cáncer de próstata en el curso de 7 años post escrutinio, con otros hombres de similares características que no desarrollaron cáncer de próstata. La sobreposición de los valores de PSA frustraron los esfuerzos de los investigadores de encontrar un valor que tenga alta especificidad así como una sensibilidad del 50%. Sin embargo, notaron que un valor de PSA menor de 1 ng/mL virtualmente descarta el diagnóstico durante el período de seguimiento.

Debido a los resultados de este estudio, se podría decir que los datos sobre los costos y beneficios de las pruebas de PSA permanecen insuficientes para apoyar el escrutinio masivo.

Referencia: Benny Holmström, et al. Prostate specific antigen for early detection of prostate cancer: longitudinal study. BMJ. Septiembre 2009;339:b3537.

De la prevención a la eugenesia


Ramón Sánchez Ocaña

Un articulo con algunos años ya, pero que que nos invita a pensar.

Ramón Sánchez Ocaña

Reflexiones sobre la actualidad sociosanitaria de un periodista especializado.

De la prevención a la eugenesia

Los avances técnicos de la medicina bordean en muchas ocasiones las fronteras éticas. Nadie duda, sin embargo, que cuando se trata de salvar una vida o librar de una enfermedad grave todas las tentativas que tengan probabilidades de éxito son plausibles. Sin embargo, tras el escaparate de las nuevas posibilidades se esconden medias verdades que sólo sirven, de momento, para alimentar esperanzas que –¡ojalá!– puedan convertirse en realidad.

No hablamos ya de las ofertas poco menos que escandalosas y abusivas de tratamientos a base de células madre que se han denunciado desde distintas instancias. Son ofertas para paliar dolencias serias, graves o crónicas en las que unas hipotéticas células madre podrían aportar algún beneficio. Es, evidentemente, una estafa aprovechando la buena fe de los enfermos y sus familias.

Otro problema más serio es la oferta de la selección embrionaria para evitar el riesgo de cáncer. Inicialmente, una pareja catalana solicitó a la Generalitat la autorización para seleccionar sus embriones y evitar así la posibilidad de que sus hijas sufrieran un cáncer de mama hereditario. Tratan, según la información recibida, de que sus vástagos femeninos no porten el gen BRCA-1, que podría desencadenar la enfermedad.

Poco después, otras familias han seguido el mismo camino y, al parecer, las autoridades correspondientes han autorizado ya algunos casos. La situación se presta a varias reflexiones.

La primera es que se pasa por alto una realidad demoledora: el cáncer no se debe a un único gen. Por lo pronto, y para el de mama, se conocen el BRCA 1 y el 2. Y se les achacan sólo el 5% de los tumores. Es decir, tras esa selección, los sujetos nacidos sin esos genes seguirán expuestos al 95% de posibilidades de un cáncer espontáneo. O debido a otros genes que se desconocen. ¿Alguien podrá asegurar que sin portar el gen se está libre de cáncer de mama cuando la realidad demuestra que el 95% de estas enfermas no tienen esos genes?

No se trata, como afirman desde fuentes oficiales, de que un sector de la población esté en contra de los avances científicos sólo porque se manipulan los embriones. Se trata de que haya una información veraz y de que, después, cada uno pueda tomar la decisión que crea más conveniente. Pero no parece ético que se oferte la posibilidad de seleccionar embriones para evitar el riesgo de cáncer, cuando ese riesgo permanece en la gran mayoría de los casos.

El problema añadido, además, es que al descubrir cada vez más enfermedades ligadas, al menos en parte, a determinados genes, se podrá ampliar la oferta de manera que, con la disculpa de tener hijos sanos, estamos bordeando, sin paliativos, la eugenesia.

¿Y qué? Se preguntarán algunos. Nada: que poco a poco estamos haciendo que el hecho biológico de procrear se convierta en un hecho mecánico. No hace mucho, cuando el Prof. Watson, que entonces era director del Proyecto Genoma, estuvo en España resumió este conflicto de una manera sumamente gráfica: “El problema –dijo– estriba en si estamos obligados a hacer el bebé perfecto”. La definición de lo que es perfecto es tema para otro día.

Cribado de cancer de prostata – Screening of prostaste cancer


Prostate and bladder, sagittal section.Image via Wikipedia

Editorial del NEJM 26 de Marzo 2009


In the United States, most men over the age of 50 years have had a prostate-specific–antigen (PSA) test,1 despite the absence of evidence from large, randomized trials of a net benefit. Moreover, about 95% of male urologists and 78% of primary care physicians who are 50 years of age or older report that they have had a PSA test themselves,2 a finding that suggests they are practicing what they preach. And indeed, U.S. death rates from prostate cancer have fallen about 4% per year since 1992, five years after the introduction of PSA testing.3 Perhaps the answer to the PSA controversy is already staring us in the face. At the same time, practice guidelines cite the unproven benefit of PSA screening, as well as the known side effects,4,5 which largely reflect the high risks of overdiagnosis and overtreatment that PSA-based screening engenders.6
The first reports from two large, randomized trials that many observers hoped would settle the controversy appear in this issue of the Journal. In the U.S. Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, Andriole et al.7 report no mortality benefit from combined screening with PSA testing and digital rectal examination during a median follow-up of 11 years.8 In the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial, Schröder et al.8 report that PSA screening without digital rectal examination was associated with a 20% relative reduction in the death rate from prostate cancer at a median follow-up of 9 years, with an absolute reduction of about 7 prostate cancer deaths per 10,000 men screened.8 The designs of the two trials are different and provide complementary insights.
First, one must ask, “Why were these results published now?” Neither set of findings seems definitive; that is, there was neither a clear declaration of futility in the PLCO trial nor an unambiguous net benefit in the ERSPC trial. Both studies are ongoing, with future updates promised. The report on the ERSPC trial follows a third planned interim analysis, which found a marginally significant decrease in prostate-cancer mortality after adjustment of the P value for the two previous looks in an attempt to avoid a false positive conclusion (yet apparently preserving no alpha for the planned final analysis). On the other hand, the investigators in the PLCO trial made the decision to publish their results now because of concern about the emerging evidence of net harm compared with potential benefits associated with PSA screening. Both decisions to publish now can be criticized as premature, leaving clinicians and patients to deal with the ambiguity.
The ERSPC trial is actually a collection of trials in different countries with different eligibility criteria, randomization schemes, and strategies for screening and follow-up. The report by Schröder et al. is based on a predefined core group of men between 55 and 69 years of age at study entry. Subjects were generally screened every 4 years, and 82% were screened at least once. Contamination of the control group with screening as part of usual care is not described. Biopsies were generally recommended for subjects with PSA levels of more than 3.0 ng per milliliter. It is unclear whether the clinicians and hospitals treating patients with prostate cancer differed between the two study groups.
Adjudications of causes of death were made by committees whose members were unaware of study-group assignments, though not of treatments. This point is important, since previous research has suggested that the cause of death is less likely to be attributed to prostate cancer among men receiving attempted curative treatment.9 Misattribution might then create a bias toward screening, since the diagnosis of more early-stage cancers in the ERSPC trial led to substantially more attempted curative treatments.
The ERSPC interim analysis revealed a 20% reduction in prostate-cancer mortality; the adjusted P value was 0.04. The estimated absolute reduction in prostate-cancer mortality of about 7 deaths per 10,000 men after 9 years of follow-up, if real and not the result of chance or bias, must be weighed against the additional interventions and burdens. The 73,000 men in the screening group underwent more than 17,000 biopsies, undoubtedly many more than did men in the control group, though the latter is not reported. Men had a substantially higher cumulative risk of receiving the diagnosis of prostate cancer in the screening group than in the control group (820 vs. 480 per 10,000 men). Diagnosis led to more treatment, with 277 versus 100 per 10,000 men undergoing radical prostatectomy and 220 versus 123 per 10,000 undergoing radiation therapy with or without hormones, respectively (tentative estimates given the unknown treatments in both groups).
Although estimates of the benefit of screening were somewhat greater for men who actually underwent testing (taking into account noncompliance) than for those who were not tested, the side effects would be proportionately higher as well. Given these trade-offs, the promise of future ERSPC analyses addressing quality of life and cost-effectiveness is welcome indeed. The ERSPC results also reemphasize the need for caution in screening men over the age of 69 years, given an early trend toward higher prostate-cancer mortality with screening in this age subgroup, although this finding may well be due to chance alone.
A final point to make about the ERSPC trial is that to the extent that the diagnosis and treatment of prostate cancer in the screening group differed from those in the control group, it becomes difficult to dissect out the benefit attributable to screening versus improved treatment once prostate cancer was suspected or diagnosed. A similar distribution of treatments among seemingly similar patients with cancer is only partially reassuring in this regard.
Despite a longer median follow-up, the PLCO trial was smaller and therefore less mature than the ERSPC trial, with 174 prostate-cancer deaths driving the power of the study, as compared with 540 such deaths in the ERSPC trial. The screening protocol was homogeneous across sites with an enrollment age of 55 to 74 years and annual PSA tests for 6 years and digital rectal examinations for 4 years, with about 85% compliance. Subjects in the screening group who had a suspicious digital rectal examination or a PSA level of more than 4.0 ng per milliliter received a recommendation for further evaluation. This strategy helped to ensure that any difference in outcome was attributable to screening, rather than downstream management. The effectiveness of screening, of course, will be determined by the effectiveness of subsequent “usual care,” but this is the same usual care that many practitioners assume has been responsible for the falling U.S. death rate from prostate cancer. Adjudication of causes of death was similar to that in the ERSPC trial.
Though the PLCO trial has shown no significant effect on prostate-cancer mortality to date, the relatively low number of end points begets a wide confidence interval, which includes at its lower margin the point estimate of effect from the ERSPC trial. Other likely explanations for the negative findings are high levels of prescreening in the PLCO population and contamination of the control group. Contamination was assessed by periodic cross-sectional surveys, with about half the subjects in the control group undergoing PSA testing by year 5. It is unclear whether these estimates reflect testing that year or since trial inception; if the former, the cumulative incidence may be even higher. The smaller difference in screening intensity between the two study groups in the PLCO trial, as compared with the ERSPC trial, is reflected in a smaller risk of overdiagnosis (23% vs. more than 70%) and a less impressive shift in cancer stage and grade distributions. Given that study-group contamination from the use of digital rectal examination was less problematic (only about 25%), ongoing results from both of these trials may necessitate rethinking the role of digital rectal examination in cancer screening.
After digesting these reports, where do we stand regarding the PSA controversy? Serial PSA screening has at best a modest effect on prostate-cancer mortality during the first decade of follow-up. This benefit comes at the cost of substantial overdiagnosis and overtreatment. It is important to remember that the key question is not whether PSA screening is effective but whether it does more good than harm. For this reason, comparisons of the ERSPC estimates of the effectiveness of PSA screening with, for example, the similarly modest effectiveness of breast-cancer screening cannot be made without simultaneously appreciating the much higher risks of overdiagnosis and overtreatment associated with PSA screening.
The report on the ERSPC trial appropriately notes that 1410 men would need to be offered screening and an additional 48 would need to be treated to prevent one prostate-cancer death during a 10-year period, assuming the point estimate is correct. And although the PLCO trial may not have the power as yet to detect a similarly modest benefit of screening, its power is already more than adequate to detect important harm through overdiagnosis. However, the implications of the trade-offs reflected in these data, like beauty, will be in the eye of the beholder. Some well-informed clinicians and patients will still see these trade-offs as favorable; others will see them as unfavorable. As a result, a shared decision-making approach to PSA screening, as recommended by most guidelines, seems more appropriate than ever.
Finally, despite these critiques, both groups of investigators deserve high praise for their persistence and perseverance: to manage such monstrous trials is a herculean task, made no easier when so many observers think the results are self-evident. Further analyses will be needed from these trials, as well as from others — such as the Prostate Cancer Intervention Versus Observation Trial (PIVOT) in the United States (ClinicalTrials.gov number, NCT00007644 [ClinicalTrials.gov] )10 and the Prostate Testing for Cancer and Treatment (PROTECT) trial in the United Kingdom (Current Controlled Trials number, ISRCTN20141297 [controlled-trials.com] )11 — if the PSA controversy is finally to sleep the big sleep.
No potential conflict of interest relevant to this article was reported.

Source Information

From Massachusetts General Hospital and Harvard Medical School, Boston.

This article (10.1056/NEJMe0901166) was published at NEJM.org on March 18, 2009.
References

  1. Ross LE, Berkowitz Z, Ekwueme DU. Use of the prostate-specific antigen test among U.S. men: findings from the 2005 National Health Interview Survey. Cancer Epidemiol Biomarkers Prev 2008;17:636-644. [Free Full Text]
  2. Chan EC, Barry MJ, Vernon SW, Ahn C. Brief report: physicians and their personal prostate cancer-screening practices with prostate-specific antigen: a national survey. J Gen Intern Med 2006;21:257-259. [CrossRef][ISI][Medline]
  3. Ries LAG, Melbert D, Krapcho M, et al. SEER cancer statistics review, 1975–2005. Bethesda, MD: National Cancer Institute, 2008. (Accessed March 6, 2009 at http://seer.cancer.gov/csr/1975_2005/.)
  4. Smith RA, Cokkinides V, Brawley OW. Cancer screening in the United States, 2008: a review of current American Cancer Society guidelines and cancer screening issues. CA Cancer J Clin 2008;58:161-179. [Free Full Text]
  5. U. S. Preventive Services Task Force. Screening for prostate cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2008;149:185-191. [Free Full Text]
  6. Barry MJ. Why are a high overdiagnosis probability and a long lead time for prostate cancer screening so important? J Natl Cancer Inst (in press).
  7. Andriole GL, Grubb RL III, Buys SS, et al. Mortality results from a randomized prostate-cancer screening trial. N Engl J Med 2009;360:1310-1319. [Free Full Text]
  8. Schröder FH, Hugosson J, Roobol MJ, et al. Screening and prostate-cancer mortality in a randomized European study. N Engl J Med 2009;360:1320-1328. [Free Full Text]
  9. Newschaffer CJ, Otani K, McDonald MK, Penberthy LT. Causes of death in elderly prostate cancer patients and in a comparison nonprostate cancer cohort. J Natl Cancer Inst 2000;92:613-621. [Free Full Text]
  10. Wilt TJ, Brawer MK, Barry MJ, et al. The Prostate cancer Intervention Versus Observation Trial: VA/NCI/AHRQ Cooperative Studies Program #407 (PIVOT): design and baseline results of a randomized controlled trial comparing radical prostatectomy to watchful waiting for men with clinically localized prostate cancer. Contemp Clin Trials 2009;30:81-87. [CrossRef][ISI][Medline]
  11. Donovan J, Hamdy F, Neal D, et al. Prostate Testing for Cancer and Treatment (ProtecT) feasibility study. Health Technol Assess 2003;7:1-88. [Medline]

Algo para leer?


Fuente: AP al Dia. 
De revistas:
En internet:
Screening for Depression in Adults[U.S. Preventive Services Task Force (USPSTF)]

Ultimo momento: Diario argentino descubre la American Task Force


Mamografias, polemica recomendación”, asi dice el diario La Nación de hoy, en relación a las nuevas guías de la “American Task Force”, quién nuevamente insiste en que las mismas deben ser realizadas cada dos años, luego de los 50 años. Como era de preveer en EE.UU., oncólogos y radiologos, se oponen. No por que le interese la salud, sino porque el negocio es la enfermedad. Es cierto que 1 de cada 8 mujeres tendrá cáncer de mama en el curso de su vida, como también es cierto que hay estudios que demuestran que reducen en un 33% la mortalidad. Poco se dice que la mayoria de las muertes se ubican por encima de los 60 años, y probablemente en nuestro pais, la mas de  las veces en mujeres que nunca se realizaron una mamografia.
Reducir la mortalidad en un 33% parece mas que contundente argumento en contra de esta recomendacion. Aunque queda relativizado cuando se lee que los estudios que ésto avalan, la reducción del cáncer pasa del 3% al 2%, es decir una caida de la mortalidad del 1%. Tampoco parece que se han tomado en cuenta la cantidad de canceres generados por las propias radiaciones, que parece que terminan dando un resultado neutro al hacer o no mamografias en forma sistematica. O que la famosa terapia de reemplazo hormonal aumenta la mortalidad, y que desde que se terminó de confirmar esto, los medicos de EEUU recomiendan menos terapia de reemplazo, lo que ha hecho caer la mortalidad por cáncer de mama en un 15%, es decir  mucho más que la propia mamografia.
En nuestro medio, decir esto es cuanto menos un pecado. Las mujeres todos los años mamografias desde los 20 años, y un papanicolau cada 6 meses. Poco importa si este exceso genera sobrediagnosticos, y menos aún que mientras se nos quiere  vender una vacuna contra el cáncer de utero, cuya eficacia no ha sido comprobada, el 70% de las mujeres de nuestro país, nunca se han realizado un papanicolau.
No solo por desconocimiento, sino también porque no en toda argentina existen anatomopatologos que procesen las muestras, o quizás porque no sea mucho el incentivo levantarse a las 4 de la mañana para sacar un turno en  un hospital para una práctica preventiva.
Que diria este diario si se entera que la recomendacion del papanicolau es de cada 2 papanicolau luego del comienzo de las relaciones sexuales, y si estos dos son normales luego uno cada 3 años ? Lejos, muy lejos de las recomendaciones de la que los ginecologos dan a las mujeres hoy. De algo hay que vivir no?
Mientras hay paises con mucho mejores indicadores de salud que Argentina, y donde el papanicolau es realizado por enfermeras simplemente bien entrenadas. En Argentina se pone el grito en el cielo si un médico de familia intenta hacerlo en alguna ciudad. Ahora si, poco importa si esto sucede en zonas rurales o semirurales. Neuquen, sigue teniendo, pese a lo que digan sus propios médicos, uno de los mejores planes de salud de Argentina. La mayoria de los papanicolau en el interior neuquino lo hacen los médicos generales, o familiares. Al igual que hacen partos. Y seguramente no van a creerlo….pero los chicos siguen vivos y las madres también. Al igual que en Holanda, o en muchos lugares de EEUU, en paises nórdicos. Pero los especialistas seguiran diciendo que nuestra especialidad sólo sirve para irse al campo.
Hace 13  años, en una experiencia con una Obra Social Nacional, en Salta, la Asociación de Patologia Cervical Uterina se opuso completamente a que realizaramos este tipo de prácticas, en plena ciudad de Salta. Tuve una charla interesante con absolutamente todos los miembros de la sociedad (que eran dos, un ginecologo y un anatomopatologo), luego de la cual creo que solo el anatomopatologo quedo convencido porque se dio cuenta que si los medicos de familia también hacian papanicolau, más muestras iba a tener para analizar, y facturar obviamente. Tan sólo una anécdota, que pinta que cómo tras “la prevencion”, no pocas veces se esconden cuantiosos dineros, que podrian ser gastados en cosas que sean más utiles a la gente.
No necesitamos vacunas para el virus HPV, necesitamos mas mujeres haciendose papanicolau. No necesitamos mas medicos, necesitamos que se dejen de acumular todos en cada lugar donde hay una facultad de medicina, mientras el sur y el norte de nuestro pais, conocen a los medicos por fotos. No necesitamos vacunas para problemas que se podrian solucionar con agua potable, y no esa que nos dan de tomar. No necesitamos pastillas para dormir, necesitamos una sociedad donde el trabajo y el saber que cada dia, uno va a volver a su casa sin miedos, seguramente hará dormir  mejor a más de uno. No necesitamos sildenafil, y menos aún cuando los que mas lo consumen son los menores de 30 años, el mejor afrodisiaco sigue siendo el amor. No necesitamos de una ley de obesidad, sino de una que permita comer a millones de Argentinos que  desayunaron esta mañana un mate, o quizas en la escuela. Pero ese mate y esa escuela, no siempre estan disponibles todo el año. Necesitamos una sociedad, simplemente más justa. Y reconocer, que la jornada laboral de 8 horas y el agua potable, fueron mas importantes en la mejoria de la salud durante el siglo XX, que todos los adelantos cientificos con que los médicos queremos hacer creer ( y que las propias universidades nos vendieron a nosotros mismos). Lease bien, la penicinlina y la vacuna de la polio sin duda han sido logros de la medicina. Pero hospitales que generan más infecciones que las que los pacientes que van para curarse de ellas, también son logros de la medicina. Y más de una terapia intensiva, o sector de neonatologia debieran cerrar algunos dias al año, al menos cada 2 años, como la recomendación de la American Task Force, y desinfectar y limpiar de virus y bacterias que cada año generan gérmenes “intrahospitalarios” (esto incluye a las clinicas y sanatorios cuya diferencia de términos desconozco), y quizás asi, evitar  más muertes que éxitos de la medicina. Pero dificilmente los dueños de estas terapias y de estas “neos”, quieran perderse los miles de pesos que cuesta cada dia de internación……ni siquiera otro sueño americano.

Antigeno Prostatico Especifico: inutil para el cribado de cancer de prostata


Todavia desconozco en que idioma hay que escribir esto, pero por enesima  vez sale otro articulo que dice que la PSA,  no tiene ninguna utilidad en el cribado de cáncer de próstata y que sólo sirve para el seguimiento de pacientes con Cáncer de prostata. El tema es simple. Se trata de una prueba inespecifica, y el famoso antigeno es volumen-dependiente del tamaño de la prostata. Por ende, en la natural evolucion que tenemos los hombres la prostata se agranda con la edad. Por tanto, ningun valor sirve para diferenciar si ese agrandamiento se  debió a la hipertrofia prostática benigna, que también es muy común luego de los 65 años. Por otro lado, un viejo anatomista,  Testut, ya escribia en su tratado que data del año 1900, que en sus autopsias encontraba un 100% de cáncer de prostata en hombres  mayores de 80 años. En otras palabras, y aunque los urólogos se empeñen en poner al cancer de próstata como un grave problema de salud, colocandolo entre las primeras causas de muerte, la realidad indica, que nos morimos más con cáncer de próstata que por el cáncer mismo. Por ende es un buen marcador de la evolución del cáncer pero no tiene ninguna utilidad, escrito en Inglés (también ha sido escrito en castellano, catalán, portugues, francés, ruso, y seguramente en esperanto) por el  British Medical Journal.
Por ende tendremos que seguir lidiando con los expertos que aparecen en la prensa de todo el mundo, e intentan convencer a la gente de hacerse estos estudios desde los 50 años. 

Utilizando una cohorte grande Seuca relacionada con un registro nacional de cáncer, los investigadores compararon los valores iniciales de PSA de aquellos que desarrollaron cáncer de próstata en el curso de 7 años post escrutinio, con otros hombres de similares características que no desarrollaron cáncer de próstata. La sobreposición de los valores de PSA frustraron los esfuerzos de los investigadores de encontrar un valor que tenga alta especificidad así como una sensibilidad del 50%. Sin embargo, notaron que un valor de PSA menor de 1 ng/mL virtualmente descarta el diagnóstico durante el período de seguimiento.

Debido a los resultados de este estudio, se podría decir que los datos sobre los costos y beneficios de las pruebas de PSA permanecen insuficientes para apoyar el escrutinio masivo.

Referencia: Benny Holmström, et al. Prostate specific antigen for early detection of prostate cancer: longitudinal study. BMJ. Septiembre 2009;339:b3537.

Cuidados dentro de la casa para pacientes con gripe


Fuente: OPS

Cómo cuidar a los demás
La mayoría de los pacientes con gripe podrá permanecer en sus casas y podrán ser atendidos por otros integrantes de la familia o personas que habiten en el hogar. Estos corren el riesgo de contagiarse gripe durante el período de incubación y enfermedad del paciente.

Manejo del paciente con gripe
Aleje físicamente al paciente lo más posible de todo el resto de las personas no enfermas que habitan en una casa. Si es posible, arme un cuarto aparte.
Es importante que el aire de la habitación circule hacia el exterior y que no vuelva a ingresar en la casa.
Sólo deben entrar a la habitación del enfermo las personas que estrictamente necesitan atenderlo, y deben lavarse bien las manos al salir.
Usar barbijos puede ser útil.
Los pacientes no deben salir de sus hogares durante el período en que es más probable que puedan contagiar a otros.

Medidas para controlar la infección en el hogar
Todas las personas en la casa deben lavarse las manos con agua y jabón o utilizar líquido de limpieza de manos con alcohol luego de entrar en contacto con un paciente que tiene gripe.
No es necesario separar los cubiertos utilizados por un paciente con gripe.
No es necesario lavar por separado la ropa de cama y otra ropa utilizada por el paciente con gripe. Hay que manejar la ropa sucia con cuidado para evitar la contaminación. Deben higienizarse las manos luego de manipular la ropa sucia.
Los pañuelos usados por un paciente enfermo deben colocarse en una bolsa y descartarse con el resto de los desechos hogareños.
Considere la posibilidad de colocar una bolsa exclusiva para ello al lado de la cama.

Manejo de otras personas en el hogar
Aquellas personas/visitantes que no han estado expuestos a la gripe y que no resultan esenciales para cuidar al paciente no deberían ingresar a la casa.
Si hay personas que no han estado expuestas y que deben ingresar a la casa, deben evitar el contacto estrecho con el paciente.
Las personas que habitan en la misma casa que el paciente con gripe deben limitar el contacto con él en la medida de lo posible; considere la posibilidad de designar una persona como cuidadora principal del paciente.
Los convivientes de dicho hogar deben estar atentos a cualquier aparición de los síntomas de la gripe

Cuidados dentro de la casa para pacientes con gripe


Fuente: OPS

Cómo cuidar a los demás
La mayoría de los pacientes con gripe podrá permanecer en sus casas y podrán ser atendidos por otros integrantes de la familia o personas que habiten en el hogar. Estos corren el riesgo de contagiarse gripe durante el período de incubación y enfermedad del paciente.

Manejo del paciente con gripe
Aleje físicamente al paciente lo más posible de todo el resto de las personas no enfermas que habitan en una casa. Si es posible, arme un cuarto aparte.
Es importante que el aire de la habitación circule hacia el exterior y que no vuelva a ingresar en la casa.
Sólo deben entrar a la habitación del enfermo las personas que estrictamente necesitan atenderlo, y deben lavarse bien las manos al salir.
Usar barbijos puede ser útil.
Los pacientes no deben salir de sus hogares durante el período en que es más probable que puedan contagiar a otros.

Medidas para controlar la infección en el hogar
Todas las personas en la casa deben lavarse las manos con agua y jabón o utilizar líquido de limpieza de manos con alcohol luego de entrar en contacto con un paciente que tiene gripe.
No es necesario separar los cubiertos utilizados por un paciente con gripe.
No es necesario lavar por separado la ropa de cama y otra ropa utilizada por el paciente con gripe. Hay que manejar la ropa sucia con cuidado para evitar la contaminación. Deben higienizarse las manos luego de manipular la ropa sucia.
Los pañuelos usados por un paciente enfermo deben colocarse en una bolsa y descartarse con el resto de los desechos hogareños.
Considere la posibilidad de colocar una bolsa exclusiva para ello al lado de la cama.

Manejo de otras personas en el hogar
Aquellas personas/visitantes que no han estado expuestos a la gripe y que no resultan esenciales para cuidar al paciente no deberían ingresar a la casa.
Si hay personas que no han estado expuestas y que deben ingresar a la casa, deben evitar el contacto estrecho con el paciente.
Las personas que habitan en la misma casa que el paciente con gripe deben limitar el contacto con él en la medida de lo posible; considere la posibilidad de designar una persona como cuidadora principal del paciente.
Los convivientes de dicho hogar deben estar atentos a cualquier aparición de los síntomas de la gripe

Prevencion


Dos excelentes articulos de Juan Gervas y Barbara Starfield sobre prevencion. Sin duda y como es de esperar, polemicos como siempre. Espero los disfruten:

Two amazing papers by Juan Gervas (Spain) and Barbara Starfield (USA) about prevention. Without doubt, as we ever expect from them, a good issue to argue the pro and cons. I hope you enjoy them as I did. Thanks Juan, Thanks Barbara. 


prevention_concept_JECH_2008.pdf


prevention_Lancet_2008_publ.pdf

prevention J.Gervas , B.Starfield
prevention J.Gerva…
Hosted by eSnips
prevencion-Gervas Starfield
prevencion-Gervas …
Hosted by eSnips

Prevencion


Dos excelentes articulos de Juan Gervas y Barbara Starfield sobre prevencion. Sin duda y como es de esperar, polemicos como siempre. Espero los disfruten:

Two amazing papers by Juan Gervas (Spain) and Barbara Starfield (USA) about prevention. Without doubt, as we ever expect from them, a good issue to argue the pro and cons. I hope you enjoy them as I did. Thanks Juan, Thanks Barbara. 


prevention_concept_JECH_2008.pdf


prevention_Lancet_2008_publ.pdf

prevention J.Gervas , B.Starfield
prevention J.Gerva…
Hosted by eSnips
prevencion-Gervas Starfield
prevencion-Gervas …
Hosted by eSnips

Quien tiene tiempo para Medicina Familiar?


Interesante articulo en el que se comenta sobre el exceso de guias de practicas clinicas y la cantidad de horas que llevaria llevar adelante las practicas preventivas que se proponen. Al menos en America del Norte, esto implicaria unas 10,5 horas por dia, cuando el promedio de horas laborables por estos medicos es de casi 8 horas.

Nicholas Pimlott, MD CCFP
Associate Professor in the Department of Family and Community Medicine at the University of Toronto, Research Director of the Family Practice Health Centre at Women’s College Hospital in Toronto, Ont., and Associate Editor of Canadian Family Physician

Correspondence to: Dr Nicholas Pimlott, 60 Grosvenor St, Toronto, ON M5S 1B6; telephone 416 323–6065; fax 416 323–6335; e-mail nick.pimlott@utoronto.ca<!– var u = "nick.pimlott", d = "utoronto.ca"; document.getElementById("em0").innerHTML = '‘ + u + ‘@’ + d + ”//–>

Recently a number of articles in the medical literature have discussed the many dissatisfactions of primary care physicians, including family physicians.

Bodenheimer1 has clearly documented the growing pressures on primary care physicians in the United States. Patients are dissatisfied as they experience longer wait times and perceive the quality of care they receive to be inadequate. Physicians are dissatisfied because they feel they are paid for volume, not quality; they earn half the income of specialists and the gap is widening; and they find that the workload is becoming impossible to sustain. The situation is similar in Canadian primary care.

Time pressures

The first published evidence examining family physician workload appeared in 2003. Yarnall et al2 used published and estimated times per service to determine the physician time required to provide all of the services recommended by the US Preventive Services Task Force, at the recommended frequency, to a patient panel of 2500 with an age and sex distribution similar to that of the US population. They found that to fully satisfy the US Preventive Services Task Force recommendations, a physician would have to spend 1773 hours per year, or 7.4 hours per working day, providing preventive services.

Recently, using similar methods, Østbye et al3 applied guideline recommendations for 10 common chronic diseases to a panel of 2500 primary care patients (with an age and sex distribution and chronic disease prevalence similar to those of the general population) and estimated the minimum physician time required to deliver high-quality care for these conditions. The result was compared with time available for patient care for the average primary care physician. They found that 823 hours per year, or 3.5 hours a day, were required to provide care for the 10 most common chronic diseases, provided the diseases were stable and in good control. They recalculated this estimate based on increased time requirements for uncontrolled disease. The estimated time required increased by a factor of 3. Applying this factor to all 10 diseases, time demands increased to 2484 hours per year or 10.6 hours a day. The authors concluded that meeting current practice guidelines for only 10 chronic illnesses requires more time than primary care physicians have available for patient care overall.

When we combine the results of these 2 studies, the average American family physician will spend between 10.9 and 18 hours per day delivering preventive and chronic illness care. Such estimates fail to account for time spent in the delivery of acute care for common conditions, such as upper respiratory tract infections and urinary tract infections, that make up much of a typical day. They also fail to account for time spent outside the examination room answering telephone calls, filling out forms, making referrals, and so on, which takes up a substantial part of the day.4,5

The situation begs some obvious questions. How did expectations for family physicians outstrip the number of hours in the day? Since even the most conscientious family physician is not working 24 hours a day,6 how do family physicians cope with such expectations and demands on their time? Finally, how can expectations of family physicians be made more realistic without compromising the quality of patient care?

Guideline explosion

Several factors have contributed to the time crunch for family physicians, but I believe one factor in particular has had an enormous effect—the explosion of clinical practice guidelines (CPGs) over the past decade. Clinical practice guidelines emerged in the 1970s in most of the industrialized world, beginning with the Canadian Task Force on the Periodic Health Examination in Canada and the US Preventive Services Task Force in the United States. The task forces had an admirable purpose and necessary goals: to evaluate the scientific evidence behind preventive care and to make evidence-based recommendations for practice. These task forces established clear evidence hierarchies and a clear process for the evaluation and the dissemination of clinical evidence. Their recommendations continue to guide primary preventive care today.

Since that time there has been an explosion of CPGs aimed at family physicians. There are more than 2000 guidelines available from the website of the National Guidelines Clearinghouse (www.guideline.gov) in the United States (although not all of them are relevant to family physicians). At last count there were 124 CPGs posted on the website (http://gacguidelines.ca) of the Ontario-based Guidelines Advisory Committee (GAC), an organization dedicated to the evaluation and dissemination of guidelines relevant to family physicians; the GAC’s mission is “to promote better health for the people of Ontario by encouraging physicians and other practitioners to use evidence-based clinical practice guidelines and clinical practices based on best available evidence. In particular, to increase awareness and use of best available evidence, [they] identify, evaluate, endorse and summarize guidelines for use in Ontario.”

While the GAC evaluates and rates CPGs according to criteria for quality, there are many problems with CPGs, including many of those that the GAC has favourably evaluated. First, there is strong evidence that guidelines are not developed according to stringent criteria. Shaneyfelt has demonstrated that “Guidelines published in the peer-reviewed medical literature during the past decade do not adhere well to established methodological standards. While all areas of guideline development need improvement, greatest improvement is needed in the identification, evaluation, and synthesis of the scientific evidence.”7 Second, guidelines follow the clinical research paradigm and are often developed with only one condition or disease in mind. Patients seen by family physicians usually present with several chronic and interacting conditions, making the application of guideline recommendations more difficult.8 Third, guidelines often do not take into account patient preferences for care, something that family physicians are explicitly trained to do. Fourth, even high-quality guidelines fall short in the way they are disseminated to family physicians. Guidelines are usually passively distributed by mail and in paper form. Although there are increasing exceptions, they also tend to be long, detailed, and do not provide specific clinically useful summaries for busy doctors.9

Improving guidelines

Is there a way to improve CPGs and to reduce the enormous time pressures that burgeoning guidelines place on family physicians? I believe that the answer is yes, but several changes in current practice and in the way that guidelines are developed and disseminated are necessary.

Guidelines need to be “done” differently. Guideline panels typically consist of large numbers of specialist content experts with 2 or 3 family physicians included. Having sat on a guideline panel in the past,10 I can reflect that much of the discussion over 2 days was about research evidence to support the recommendations. While this discussion is critically important, very little time was spent on the equally important issue of dissemination (or knowledge translation). This is a world turned upside down. I propose that guideline panels of the future have much greater representation from family physicians working in different settings, with a small number of content experts to advise them on content. In that way, perhaps, greater attention will be paid to how family physicians can use the guidelines in their practices.

Greater emphasis needs to be placed on applying guidelines to the type of patients seen in family practice settings—the elderly and those with multiple chronic conditions. Furthermore, greater attention needs to be placed on the evidence for the effectiveness of interventions in guidelines. Family physicians are swamped with maneuvers supported only by expert opinion.

This has been said and written many times before, but more attention needs to be paid to the effective dissemination and implementation of good guidelines. Stronger input from family physicians is crucial if dissemination is to be successful.

As family physicians move toward working in family health teams or groups that incorporate and integrate other health care professionals, greater attention needs to be paid to the role of other providers in the delivery of acute, chronic, and preventive care. Clearly, if family physicians are to continue to provide high-quality care and incorporate guideline recommendations into their practices, they will need to share this work with other professionals. Many preventive care maneuvers can be performed, for example, by nurse practitioners integrated into family health teams. Similarly, nurse practitioners can effectively provide care for some chronic conditions, allowing family physicians to focus on acute care or on patients with chronic illnesses that are unstable.

Family physicians are under increasing time pressures to provide both preventive and chronic illness care. The growth in CPGs for both preventive and chronic care and the expectation that they will be closely followed by family physicians has contributed substantially to the time pressures. Improvements in the quality and in the dissemination of guidelines and the integration of other health care providers, such as nurse practitioners, into family health teams could help ease time pressures on family physicians and improve the quality of their work lives.

Footnotes

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

References

  1. Bodenheimer T. Primary care—will it survive? New Engl J Med 2006;355:861-4.[Free Full Text]
  2. Yarnall KS, Pollak KI, Østbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-41.[Abstract/Free Full Text]
  3. Østbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-14.[Abstract/Free Full Text]
  4. Gilchrist V, McCord G, Schrop SL, King BD, McCormick KF, Oprandi AM, et al. Physician activities during time out of the examination room. Ann Fam Med 2005;3:494-9.[Abstract/Free Full Text]
  5. Gottschalk A, Flocke SA. Time spent in face-to-face patient care and work outside the examination room. Ann Fam Med 2005;3:488-93.[Abstract/Free Full Text]
  6. Slade S, Busing N. Weekly work hours and clinical activities of Canadian family physicians: results of the 1997–98 National Family Physician Survey of the College of Family Physicians of Canada. CMAJ 2002;166:1407-11.[Abstract/Free Full Text]
  7. Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature. JAMA 1999;281:1900-5.[Abstract/Free Full Text]
  8. Upshur RE. The complex, the exhausted and the personal: reflections on the relationship between evidence-based medicine and casuistry. Commentary on Tonelli (2006), Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12(3):281-8.[Medline]
  9. Michie S, Johnston M. Changing clinical behaviour by making guidelines specific. BMJ 2004;328:343-5.[Free Full Text]
  10. Ontario Ministry of Health and Long-Term Care. Ontario guidelines for the prevention and treatment of osteoporosis. Ontario Program for Optimal Therapeutics. Toronto, ON: Ontario Ministry of Health and Long-Term Care; 2000. Available from: www.opot.org/guidelines/osteoporosis.pdf. Accessed 2007 November 27.

Fuente:

Who has time for family medicine?

Nicholas Pimlott, MD CCFP
Associate Professor in the Department of Family and Community Medicine at the University of Toronto, Research Director of the Family Practice Health Centre at Women’s College Hospital in Toronto, Ont., and Associate Editor of Canadian Family Physician

Correspondence to: Dr Nicholas Pimlott, 60 Grosvenor St, Toronto, ON M5S 1B6; telephone 416 323–6065; fax 416 323–6335; e-mail nick.pimlott@utoronto.ca<!– var u = "nick.pimlott", d = "utoronto.ca"; document.getElementById("em0").innerHTML = '‘ + u + ‘@’ + d + ”//–>

Recently a number of articles in the medical literature have discussed the many dissatisfactions of primary care physicians, including family physicians.

Bodenheimer1 has clearly documented the growing pressures on primary care physicians in the United States. Patients are dissatisfied as they experience longer wait times and perceive the quality of care they receive to be inadequate. Physicians are dissatisfied because they feel they are paid for volume, not quality; they earn half the income of specialists and the gap is widening; and they find that the workload is becoming impossible to sustain. The situation is similar in Canadian primary care.

Time pressures

The first published evidence examining family physician workload appeared in 2003. Yarnall et al2 used published and estimated times per service to determine the physician time required to provide all of the services recommended by the US Preventive Services Task Force, at the recommended frequency, to a patient panel of 2500 with an age and sex distribution similar to that of the US population. They found that to fully satisfy the US Preventive Services Task Force recommendations, a physician would have to spend 1773 hours per year, or 7.4 hours per working day, providing preventive services.

Recently, using similar methods, Østbye et al3 applied guideline recommendations for 10 common chronic diseases to a panel of 2500 primary care patients (with an age and sex distribution and chronic disease prevalence similar to those of the general population) and estimated the minimum physician time required to deliver high-quality care for these conditions. The result was compared with time available for patient care for the average primary care physician. They found that 823 hours per year, or 3.5 hours a day, were required to provide care for the 10 most common chronic diseases, provided the diseases were stable and in good control. They recalculated this estimate based on increased time requirements for uncontrolled disease. The estimated time required increased by a factor of 3. Applying this factor to all 10 diseases, time demands increased to 2484 hours per year or 10.6 hours a day. The authors concluded that meeting current practice guidelines for only 10 chronic illnesses requires more time than primary care physicians have available for patient care overall.

When we combine the results of these 2 studies, the average American family physician will spend between 10.9 and 18 hours per day delivering preventive and chronic illness care. Such estimates fail to account for time spent in the delivery of acute care for common conditions, such as upper respiratory tract infections and urinary tract infections, that make up much of a typical day. They also fail to account for time spent outside the examination room answering telephone calls, filling out forms, making referrals, and so on, which takes up a substantial part of the day.4,5

The situation begs some obvious questions. How did expectations for family physicians outstrip the number of hours in the day? Since even the most conscientious family physician is not working 24 hours a day,6 how do family physicians cope with such expectations and demands on their time? Finally, how can expectations of family physicians be made more realistic without compromising the quality of patient care?

Guideline explosion

Several factors have contributed to the time crunch for family physicians, but I believe one factor in particular has had an enormous effect—the explosion of clinical practice guidelines (CPGs) over the past decade. Clinical practice guidelines emerged in the 1970s in most of the industrialized world, beginning with the Canadian Task Force on the Periodic Health Examination in Canada and the US Preventive Services Task Force in the United States. The task forces had an admirable purpose and necessary goals: to evaluate the scientific evidence behind preventive care and to make evidence-based recommendations for practice. These task forces established clear evidence hierarchies and a clear process for the evaluation and the dissemination of clinical evidence. Their recommendations continue to guide primary preventive care today.

Since that time there has been an explosion of CPGs aimed at family physicians. There are more than 2000 guidelines available from the website of the National Guidelines Clearinghouse (www.guideline.gov) in the United States (although not all of them are relevant to family physicians). At last count there were 124 CPGs posted on the website (http://gacguidelines.ca) of the Ontario-based Guidelines Advisory Committee (GAC), an organization dedicated to the evaluation and dissemination of guidelines relevant to family physicians; the GAC’s mission is “to promote better health for the people of Ontario by encouraging physicians and other practitioners to use evidence-based clinical practice guidelines and clinical practices based on best available evidence. In particular, to increase awareness and use of best available evidence, [they] identify, evaluate, endorse and summarize guidelines for use in Ontario.”

While the GAC evaluates and rates CPGs according to criteria for quality, there are many problems with CPGs, including many of those that the GAC has favourably evaluated. First, there is strong evidence that guidelines are not developed according to stringent criteria. Shaneyfelt has demonstrated that “Guidelines published in the peer-reviewed medical literature during the past decade do not adhere well to established methodological standards. While all areas of guideline development need improvement, greatest improvement is needed in the identification, evaluation, and synthesis of the scientific evidence.”7 Second, guidelines follow the clinical research paradigm and are often developed with only one condition or disease in mind. Patients seen by family physicians usually present with several chronic and interacting conditions, making the application of guideline recommendations more difficult.8 Third, guidelines often do not take into account patient preferences for care, something that family physicians are explicitly trained to do. Fourth, even high-quality guidelines fall short in the way they are disseminated to family physicians. Guidelines are usually passively distributed by mail and in paper form. Although there are increasing exceptions, they also tend to be long, detailed, and do not provide specific clinically useful summaries for busy doctors.9

Improving guidelines

Is there a way to improve CPGs and to reduce the enormous time pressures that burgeoning guidelines place on family physicians? I believe that the answer is yes, but several changes in current practice and in the way that guidelines are developed and disseminated are necessary.

Guidelines need to be “done” differently. Guideline panels typically consist of large numbers of specialist content experts with 2 or 3 family physicians included. Having sat on a guideline panel in the past,10 I can reflect that much of the discussion over 2 days was about research evidence to support the recommendations. While this discussion is critically important, very little time was spent on the equally important issue of dissemination (or knowledge translation). This is a world turned upside down. I propose that guideline panels of the future have much greater representation from family physicians working in different settings, with a small number of content experts to advise them on content. In that way, perhaps, greater attention will be paid to how family physicians can use the guidelines in their practices.

Greater emphasis needs to be placed on applying guidelines to the type of patients seen in family practice settings—the elderly and those with multiple chronic conditions. Furthermore, greater attention needs to be placed on the evidence for the effectiveness of interventions in guidelines. Family physicians are swamped with maneuvers supported only by expert opinion.

This has been said and written many times before, but more attention needs to be paid to the effective dissemination and implementation of good guidelines. Stronger input from family physicians is crucial if dissemination is to be successful.

As family physicians move toward working in family health teams or groups that incorporate and integrate other health care professionals, greater attention needs to be paid to the role of other providers in the delivery of acute, chronic, and preventive care. Clearly, if family physicians are to continue to provide high-quality care and incorporate guideline recommendations into their practices, they will need to share this work with other professionals. Many preventive care maneuvers can be performed, for example, by nurse practitioners integrated into family health teams. Similarly, nurse practitioners can effectively provide care for some chronic conditions, allowing family physicians to focus on acute care or on patients with chronic illnesses that are unstable.

Family physicians are under increasing time pressures to provide both preventive and chronic illness care. The growth in CPGs for both preventive and chronic care and the expectation that they will be closely followed by family physicians has contributed substantially to the time pressures. Improvements in the quality and in the dissemination of guidelines and the integration of other health care providers, such as nurse practitioners, into family health teams could help ease time pressures on family physicians and improve the quality of their work lives.

Footnotes

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

References

  1. Bodenheimer T. Primary care—will it survive? New Engl J Med 2006;355:861-4.[Free Full Text]
  2. Yarnall KS, Pollak KI, Østbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-41.[Abstract/Free Full Text]
  3. Østbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-14.[Abstract/Free Full Text]
  4. Gilchrist V, McCord G, Schrop SL, King BD, McCormick KF, Oprandi AM, et al. Physician activities during time out of the examination room. Ann Fam Med 2005;3:494-9.[Abstract/Free Full Text]
  5. Gottschalk A, Flocke SA. Time spent in face-to-face patient care and work outside the examination room. Ann Fam Med 2005;3:488-93.[Abstract/Free Full Text]
  6. Slade S, Busing N. Weekly work hours and clinical activities of Canadian family physicians: results of the 1997–98 National Family Physician Survey of the College of Family Physicians of Canada. CMAJ 2002;166:1407-11.[Abstract/Free Full Text]
  7. Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature. JAMA 1999;281:1900-5.[Abstract/Free Full Text]
  8. Upshur RE. The complex, the exhausted and the personal: reflections on the relationship between evidence-based medicine and casuistry. Commentary on Tonelli (2006), Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12(3):281-8.[Medline]
  9. Michie S, Johnston M. Changing clinical behaviour by making guidelines specific. BMJ 2004;328:343-5.[Free Full Text]
  10. Ontario Ministry of Health and Long-Term Care. Ontario guidelines for the prevention and treatment of osteoporosis. Ontario Program for Optimal Therapeutics. Toronto, ON: Ontario Ministry of Health and Long-Term Care; 2000. Available from: www.opot.org/guidelines/osteoporosis.pdf. Accessed 2007 November 27.

Who has time for family medicine?

Nicholas Pimlott, MD CCFP
Associate Professor in the Department of Family and Community Medicine at the University of Toronto, Research Director of the Family Practice Health Centre at Women’s College Hospital in Toronto, Ont., and Associate Editor of Canadian Family Physician

Correspondence to: Dr Nicholas Pimlott, 60 Grosvenor St, Toronto, ON M5S 1B6; telephone 416 323–6065; fax 416 323–6335; e-mail nick.pimlott@utoronto.ca<!– var u = "nick.pimlott", d = "utoronto.ca"; document.getElementById("em0").innerHTML = '‘ + u + ‘@’ + d + ”//–>

Recently a number of articles in the medical literature have discussed the many dissatisfactions of primary care physicians, including family physicians.

Bodenheimer1 has clearly documented the growing pressures on primary care physicians in the United States. Patients are dissatisfied as they experience longer wait times and perceive the quality of care they receive to be inadequate. Physicians are dissatisfied because they feel they are paid for volume, not quality; they earn half the income of specialists and the gap is widening; and they find that the workload is becoming impossible to sustain. The situation is similar in Canadian primary care.

Time pressures

The first published evidence examining family physician workload appeared in 2003. Yarnall et al2 used published and estimated times per service to determine the physician time required to provide all of the services recommended by the US Preventive Services Task Force, at the recommended frequency, to a patient panel of 2500 with an age and sex distribution similar to that of the US population. They found that to fully satisfy the US Preventive Services Task Force recommendations, a physician would have to spend 1773 hours per year, or 7.4 hours per working day, providing preventive services.

Recently, using similar methods, Østbye et al3 applied guideline recommendations for 10 common chronic diseases to a panel of 2500 primary care patients (with an age and sex distribution and chronic disease prevalence similar to those of the general population) and estimated the minimum physician time required to deliver high-quality care for these conditions. The result was compared with time available for patient care for the average primary care physician. They found that 823 hours per year, or 3.5 hours a day, were required to provide care for the 10 most common chronic diseases, provided the diseases were stable and in good control. They recalculated this estimate based on increased time requirements for uncontrolled disease. The estimated time required increased by a factor of 3. Applying this factor to all 10 diseases, time demands increased to 2484 hours per year or 10.6 hours a day. The authors concluded that meeting current practice guidelines for only 10 chronic illnesses requires more time than primary care physicians have available for patient care overall.

When we combine the results of these 2 studies, the average American family physician will spend between 10.9 and 18 hours per day delivering preventive and chronic illness care. Such estimates fail to account for time spent in the delivery of acute care for common conditions, such as upper respiratory tract infections and urinary tract infections, that make up much of a typical day. They also fail to account for time spent outside the examination room answering telephone calls, filling out forms, making referrals, and so on, which takes up a substantial part of the day.4,5

The situation begs some obvious questions. How did expectations for family physicians outstrip the number of hours in the day? Since even the most conscientious family physician is not working 24 hours a day,6 how do family physicians cope with such expectations and demands on their time? Finally, how can expectations of family physicians be made more realistic without compromising the quality of patient care?

Guideline explosion

Several factors have contributed to the time crunch for family physicians, but I believe one factor in particular has had an enormous effect—the explosion of clinical practice guidelines (CPGs) over the past decade. Clinical practice guidelines emerged in the 1970s in most of the industrialized world, beginning with the Canadian Task Force on the Periodic Health Examination in Canada and the US Preventive Services Task Force in the United States. The task forces had an admirable purpose and necessary goals: to evaluate the scientific evidence behind preventive care and to make evidence-based recommendations for practice. These task forces established clear evidence hierarchies and a clear process for the evaluation and the dissemination of clinical evidence. Their recommendations continue to guide primary preventive care today.

Since that time there has been an explosion of CPGs aimed at family physicians. There are more than 2000 guidelines available from the website of the National Guidelines Clearinghouse (www.guideline.gov) in the United States (although not all of them are relevant to family physicians). At last count there were 124 CPGs posted on the website (http://gacguidelines.ca) of the Ontario-based Guidelines Advisory Committee (GAC), an organization dedicated to the evaluation and dissemination of guidelines relevant to family physicians; the GAC’s mission is “to promote better health for the people of Ontario by encouraging physicians and other practitioners to use evidence-based clinical practice guidelines and clinical practices based on best available evidence. In particular, to increase awareness and use of best available evidence, [they] identify, evaluate, endorse and summarize guidelines for use in Ontario.”

While the GAC evaluates and rates CPGs according to criteria for quality, there are many problems with CPGs, including many of those that the GAC has favourably evaluated. First, there is strong evidence that guidelines are not developed according to stringent criteria. Shaneyfelt has demonstrated that “Guidelines published in the peer-reviewed medical literature during the past decade do not adhere well to established methodological standards. While all areas of guideline development need improvement, greatest improvement is needed in the identification, evaluation, and synthesis of the scientific evidence.”7 Second, guidelines follow the clinical research paradigm and are often developed with only one condition or disease in mind. Patients seen by family physicians usually present with several chronic and interacting conditions, making the application of guideline recommendations more difficult.8 Third, guidelines often do not take into account patient preferences for care, something that family physicians are explicitly trained to do. Fourth, even high-quality guidelines fall short in the way they are disseminated to family physicians. Guidelines are usually passively distributed by mail and in paper form. Although there are increasing exceptions, they also tend to be long, detailed, and do not provide specific clinically useful summaries for busy doctors.9

Improving guidelines

Is there a way to improve CPGs and to reduce the enormous time pressures that burgeoning guidelines place on family physicians? I believe that the answer is yes, but several changes in current practice and in the way that guidelines are developed and disseminated are necessary.

Guidelines need to be “done” differently. Guideline panels typically consist of large numbers of specialist content experts with 2 or 3 family physicians included. Having sat on a guideline panel in the past,10 I can reflect that much of the discussion over 2 days was about research evidence to support the recommendations. While this discussion is critically important, very little time was spent on the equally important issue of dissemination (or knowledge translation). This is a world turned upside down. I propose that guideline panels of the future have much greater representation from family physicians working in different settings, with a small number of content experts to advise them on content. In that way, perhaps, greater attention will be paid to how family physicians can use the guidelines in their practices.

Greater emphasis needs to be placed on applying guidelines to the type of patients seen in family practice settings—the elderly and those with multiple chronic conditions. Furthermore, greater attention needs to be placed on the evidence for the effectiveness of interventions in guidelines. Family physicians are swamped with maneuvers supported only by expert opinion.

This has been said and written many times before, but more attention needs to be paid to the effective dissemination and implementation of good guidelines. Stronger input from family physicians is crucial if dissemination is to be successful.

As family physicians move toward working in family health teams or groups that incorporate and integrate other health care professionals, greater attention needs to be paid to the role of other providers in the delivery of acute, chronic, and preventive care. Clearly, if family physicians are to continue to provide high-quality care and incorporate guideline recommendations into their practices, they will need to share this work with other professionals. Many preventive care maneuvers can be performed, for example, by nurse practitioners integrated into family health teams. Similarly, nurse practitioners can effectively provide care for some chronic conditions, allowing family physicians to focus on acute care or on patients with chronic illnesses that are unstable.

Family physicians are under increasing time pressures to provide both preventive and chronic illness care. The growth in CPGs for both preventive and chronic care and the expectation that they will be closely followed by family physicians has contributed substantially to the time pressures. Improvements in the quality and in the dissemination of guidelines and the integration of other health care providers, such as nurse practitioners, into family health teams could help ease time pressures on family physicians and improve the quality of their work lives.

Footnotes

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

References

  1. Bodenheimer T. Primary care—will it survive? New Engl J Med 2006;355:861-4.[Free Full Text]
  2. Yarnall KS, Pollak KI, Østbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-41.[Abstract/Free Full Text]
  3. Østbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-14.[Abstract/Free Full Text]
  4. Gilchrist V, McCord G, Schrop SL, King BD, McCormick KF, Oprandi AM, et al. Physician activities during time out of the examination room. Ann Fam Med 2005;3:494-9.[Abstract/Free Full Text]
  5. Gottschalk A, Flocke SA. Time spent in face-to-face patient care and work outside the examination room. Ann Fam Med 2005;3:488-93.[Abstract/Free Full Text]
  6. Slade S, Busing N. Weekly work hours and clinical activities of Canadian family physicians: results of the 1997–98 National Family Physician Survey of the College of Family Physicians of Canada. CMAJ 2002;166:1407-11.[Abstract/Free Full Text]
  7. Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature. JAMA 1999;281:1900-5.[Abstract/Free Full Text]
  8. Upshur RE. The complex, the exhausted and the personal: reflections on the relationship between evidence-based medicine and casuistry. Commentary on Tonelli (2006), Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12(3):281-8.[Medline]
  9. Michie S, Johnston M. Changing clinical behaviour by making guidelines specific. BMJ 2004;328:343-5.[Free Full Text]
  10. Ontario Ministry of Health and Long-Term Care. Ontario guidelines for the prevention and treatment of osteoporosis. Ontario Program for Optimal Therapeutics. Toronto, ON: Ontario Ministry of Health and Long-Term Care; 2000. Available from: www.opot.org/guidelines/osteoporosis.pdf. Accessed 2007 November 27.

http://www.cfp.ca/cgi/content/full/54/1/14

Quien tiene tiempo para Medicina Familiar?


Interesante articulo en el que se comenta sobre el exceso de guias de practicas clinicas y la cantidad de horas que llevaria llevar adelante las practicas preventivas que se proponen. Al menos en America del Norte, esto implicaria unas 10,5 horas por dia, cuando el promedio de horas laborables por estos medicos es de casi 8 horas.

Nicholas Pimlott, MD CCFP
Associate Professor in the Department of Family and Community Medicine at the University of Toronto, Research Director of the Family Practice Health Centre at Women’s College Hospital in Toronto, Ont., and Associate Editor of Canadian Family Physician

Correspondence to: Dr Nicholas Pimlott, 60 Grosvenor St, Toronto, ON M5S 1B6; telephone 416 323–6065; fax 416 323–6335; e-mail nick.pimlott@utoronto.ca<!– var u = "nick.pimlott", d = "utoronto.ca"; document.getElementById("em0").innerHTML = '‘ + u + ‘@’ + d + ”//–>

Recently a number of articles in the medical literature have discussed the many dissatisfactions of primary care physicians, including family physicians.

Bodenheimer1 has clearly documented the growing pressures on primary care physicians in the United States. Patients are dissatisfied as they experience longer wait times and perceive the quality of care they receive to be inadequate. Physicians are dissatisfied because they feel they are paid for volume, not quality; they earn half the income of specialists and the gap is widening; and they find that the workload is becoming impossible to sustain. The situation is similar in Canadian primary care.

Time pressures

The first published evidence examining family physician workload appeared in 2003. Yarnall et al2 used published and estimated times per service to determine the physician time required to provide all of the services recommended by the US Preventive Services Task Force, at the recommended frequency, to a patient panel of 2500 with an age and sex distribution similar to that of the US population. They found that to fully satisfy the US Preventive Services Task Force recommendations, a physician would have to spend 1773 hours per year, or 7.4 hours per working day, providing preventive services.

Recently, using similar methods, Østbye et al3 applied guideline recommendations for 10 common chronic diseases to a panel of 2500 primary care patients (with an age and sex distribution and chronic disease prevalence similar to those of the general population) and estimated the minimum physician time required to deliver high-quality care for these conditions. The result was compared with time available for patient care for the average primary care physician. They found that 823 hours per year, or 3.5 hours a day, were required to provide care for the 10 most common chronic diseases, provided the diseases were stable and in good control. They recalculated this estimate based on increased time requirements for uncontrolled disease. The estimated time required increased by a factor of 3. Applying this factor to all 10 diseases, time demands increased to 2484 hours per year or 10.6 hours a day. The authors concluded that meeting current practice guidelines for only 10 chronic illnesses requires more time than primary care physicians have available for patient care overall.

When we combine the results of these 2 studies, the average American family physician will spend between 10.9 and 18 hours per day delivering preventive and chronic illness care. Such estimates fail to account for time spent in the delivery of acute care for common conditions, such as upper respiratory tract infections and urinary tract infections, that make up much of a typical day. They also fail to account for time spent outside the examination room answering telephone calls, filling out forms, making referrals, and so on, which takes up a substantial part of the day.4,5

The situation begs some obvious questions. How did expectations for family physicians outstrip the number of hours in the day? Since even the most conscientious family physician is not working 24 hours a day,6 how do family physicians cope with such expectations and demands on their time? Finally, how can expectations of family physicians be made more realistic without compromising the quality of patient care?

Guideline explosion

Several factors have contributed to the time crunch for family physicians, but I believe one factor in particular has had an enormous effect—the explosion of clinical practice guidelines (CPGs) over the past decade. Clinical practice guidelines emerged in the 1970s in most of the industrialized world, beginning with the Canadian Task Force on the Periodic Health Examination in Canada and the US Preventive Services Task Force in the United States. The task forces had an admirable purpose and necessary goals: to evaluate the scientific evidence behind preventive care and to make evidence-based recommendations for practice. These task forces established clear evidence hierarchies and a clear process for the evaluation and the dissemination of clinical evidence. Their recommendations continue to guide primary preventive care today.

Since that time there has been an explosion of CPGs aimed at family physicians. There are more than 2000 guidelines available from the website of the National Guidelines Clearinghouse (www.guideline.gov) in the United States (although not all of them are relevant to family physicians). At last count there were 124 CPGs posted on the website (http://gacguidelines.ca) of the Ontario-based Guidelines Advisory Committee (GAC), an organization dedicated to the evaluation and dissemination of guidelines relevant to family physicians; the GAC’s mission is “to promote better health for the people of Ontario by encouraging physicians and other practitioners to use evidence-based clinical practice guidelines and clinical practices based on best available evidence. In particular, to increase awareness and use of best available evidence, [they] identify, evaluate, endorse and summarize guidelines for use in Ontario.”

While the GAC evaluates and rates CPGs according to criteria for quality, there are many problems with CPGs, including many of those that the GAC has favourably evaluated. First, there is strong evidence that guidelines are not developed according to stringent criteria. Shaneyfelt has demonstrated that “Guidelines published in the peer-reviewed medical literature during the past decade do not adhere well to established methodological standards. While all areas of guideline development need improvement, greatest improvement is needed in the identification, evaluation, and synthesis of the scientific evidence.”7 Second, guidelines follow the clinical research paradigm and are often developed with only one condition or disease in mind. Patients seen by family physicians usually present with several chronic and interacting conditions, making the application of guideline recommendations more difficult.8 Third, guidelines often do not take into account patient preferences for care, something that family physicians are explicitly trained to do. Fourth, even high-quality guidelines fall short in the way they are disseminated to family physicians. Guidelines are usually passively distributed by mail and in paper form. Although there are increasing exceptions, they also tend to be long, detailed, and do not provide specific clinically useful summaries for busy doctors.9

Improving guidelines

Is there a way to improve CPGs and to reduce the enormous time pressures that burgeoning guidelines place on family physicians? I believe that the answer is yes, but several changes in current practice and in the way that guidelines are developed and disseminated are necessary.

Guidelines need to be “done” differently. Guideline panels typically consist of large numbers of specialist content experts with 2 or 3 family physicians included. Having sat on a guideline panel in the past,10 I can reflect that much of the discussion over 2 days was about research evidence to support the recommendations. While this discussion is critically important, very little time was spent on the equally important issue of dissemination (or knowledge translation). This is a world turned upside down. I propose that guideline panels of the future have much greater representation from family physicians working in different settings, with a small number of content experts to advise them on content. In that way, perhaps, greater attention will be paid to how family physicians can use the guidelines in their practices.

Greater emphasis needs to be placed on applying guidelines to the type of patients seen in family practice settings—the elderly and those with multiple chronic conditions. Furthermore, greater attention needs to be placed on the evidence for the effectiveness of interventions in guidelines. Family physicians are swamped with maneuvers supported only by expert opinion.

This has been said and written many times before, but more attention needs to be paid to the effective dissemination and implementation of good guidelines. Stronger input from family physicians is crucial if dissemination is to be successful.

As family physicians move toward working in family health teams or groups that incorporate and integrate other health care professionals, greater attention needs to be paid to the role of other providers in the delivery of acute, chronic, and preventive care. Clearly, if family physicians are to continue to provide high-quality care and incorporate guideline recommendations into their practices, they will need to share this work with other professionals. Many preventive care maneuvers can be performed, for example, by nurse practitioners integrated into family health teams. Similarly, nurse practitioners can effectively provide care for some chronic conditions, allowing family physicians to focus on acute care or on patients with chronic illnesses that are unstable.

Family physicians are under increasing time pressures to provide both preventive and chronic illness care. The growth in CPGs for both preventive and chronic care and the expectation that they will be closely followed by family physicians has contributed substantially to the time pressures. Improvements in the quality and in the dissemination of guidelines and the integration of other health care providers, such as nurse practitioners, into family health teams could help ease time pressures on family physicians and improve the quality of their work lives.

Footnotes

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

References

  1. Bodenheimer T. Primary care—will it survive? New Engl J Med 2006;355:861-4.[Free Full Text]
  2. Yarnall KS, Pollak KI, Østbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-41.[Abstract/Free Full Text]
  3. Østbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-14.[Abstract/Free Full Text]
  4. Gilchrist V, McCord G, Schrop SL, King BD, McCormick KF, Oprandi AM, et al. Physician activities during time out of the examination room. Ann Fam Med 2005;3:494-9.[Abstract/Free Full Text]
  5. Gottschalk A, Flocke SA. Time spent in face-to-face patient care and work outside the examination room. Ann Fam Med 2005;3:488-93.[Abstract/Free Full Text]
  6. Slade S, Busing N. Weekly work hours and clinical activities of Canadian family physicians: results of the 1997–98 National Family Physician Survey of the College of Family Physicians of Canada. CMAJ 2002;166:1407-11.[Abstract/Free Full Text]
  7. Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature. JAMA 1999;281:1900-5.[Abstract/Free Full Text]
  8. Upshur RE. The complex, the exhausted and the personal: reflections on the relationship between evidence-based medicine and casuistry. Commentary on Tonelli (2006), Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12(3):281-8.[Medline]
  9. Michie S, Johnston M. Changing clinical behaviour by making guidelines specific. BMJ 2004;328:343-5.[Free Full Text]
  10. Ontario Ministry of Health and Long-Term Care. Ontario guidelines for the prevention and treatment of osteoporosis. Ontario Program for Optimal Therapeutics. Toronto, ON: Ontario Ministry of Health and Long-Term Care; 2000. Available from: www.opot.org/guidelines/osteoporosis.pdf. Accessed 2007 November 27.

Fuente:

Who has time for family medicine?

Nicholas Pimlott, MD CCFP
Associate Professor in the Department of Family and Community Medicine at the University of Toronto, Research Director of the Family Practice Health Centre at Women’s College Hospital in Toronto, Ont., and Associate Editor of Canadian Family Physician

Correspondence to: Dr Nicholas Pimlott, 60 Grosvenor St, Toronto, ON M5S 1B6; telephone 416 323–6065; fax 416 323–6335; e-mail nick.pimlott@utoronto.ca<!– var u = "nick.pimlott", d = "utoronto.ca"; document.getElementById("em0").innerHTML = '‘ + u + ‘@’ + d + ”//–>

Recently a number of articles in the medical literature have discussed the many dissatisfactions of primary care physicians, including family physicians.

Bodenheimer1 has clearly documented the growing pressures on primary care physicians in the United States. Patients are dissatisfied as they experience longer wait times and perceive the quality of care they receive to be inadequate. Physicians are dissatisfied because they feel they are paid for volume, not quality; they earn half the income of specialists and the gap is widening; and they find that the workload is becoming impossible to sustain. The situation is similar in Canadian primary care.

Time pressures

The first published evidence examining family physician workload appeared in 2003. Yarnall et al2 used published and estimated times per service to determine the physician time required to provide all of the services recommended by the US Preventive Services Task Force, at the recommended frequency, to a patient panel of 2500 with an age and sex distribution similar to that of the US population. They found that to fully satisfy the US Preventive Services Task Force recommendations, a physician would have to spend 1773 hours per year, or 7.4 hours per working day, providing preventive services.

Recently, using similar methods, Østbye et al3 applied guideline recommendations for 10 common chronic diseases to a panel of 2500 primary care patients (with an age and sex distribution and chronic disease prevalence similar to those of the general population) and estimated the minimum physician time required to deliver high-quality care for these conditions. The result was compared with time available for patient care for the average primary care physician. They found that 823 hours per year, or 3.5 hours a day, were required to provide care for the 10 most common chronic diseases, provided the diseases were stable and in good control. They recalculated this estimate based on increased time requirements for uncontrolled disease. The estimated time required increased by a factor of 3. Applying this factor to all 10 diseases, time demands increased to 2484 hours per year or 10.6 hours a day. The authors concluded that meeting current practice guidelines for only 10 chronic illnesses requires more time than primary care physicians have available for patient care overall.

When we combine the results of these 2 studies, the average American family physician will spend between 10.9 and 18 hours per day delivering preventive and chronic illness care. Such estimates fail to account for time spent in the delivery of acute care for common conditions, such as upper respiratory tract infections and urinary tract infections, that make up much of a typical day. They also fail to account for time spent outside the examination room answering telephone calls, filling out forms, making referrals, and so on, which takes up a substantial part of the day.4,5

The situation begs some obvious questions. How did expectations for family physicians outstrip the number of hours in the day? Since even the most conscientious family physician is not working 24 hours a day,6 how do family physicians cope with such expectations and demands on their time? Finally, how can expectations of family physicians be made more realistic without compromising the quality of patient care?

Guideline explosion

Several factors have contributed to the time crunch for family physicians, but I believe one factor in particular has had an enormous effect—the explosion of clinical practice guidelines (CPGs) over the past decade. Clinical practice guidelines emerged in the 1970s in most of the industrialized world, beginning with the Canadian Task Force on the Periodic Health Examination in Canada and the US Preventive Services Task Force in the United States. The task forces had an admirable purpose and necessary goals: to evaluate the scientific evidence behind preventive care and to make evidence-based recommendations for practice. These task forces established clear evidence hierarchies and a clear process for the evaluation and the dissemination of clinical evidence. Their recommendations continue to guide primary preventive care today.

Since that time there has been an explosion of CPGs aimed at family physicians. There are more than 2000 guidelines available from the website of the National Guidelines Clearinghouse (www.guideline.gov) in the United States (although not all of them are relevant to family physicians). At last count there were 124 CPGs posted on the website (http://gacguidelines.ca) of the Ontario-based Guidelines Advisory Committee (GAC), an organization dedicated to the evaluation and dissemination of guidelines relevant to family physicians; the GAC’s mission is “to promote better health for the people of Ontario by encouraging physicians and other practitioners to use evidence-based clinical practice guidelines and clinical practices based on best available evidence. In particular, to increase awareness and use of best available evidence, [they] identify, evaluate, endorse and summarize guidelines for use in Ontario.”

While the GAC evaluates and rates CPGs according to criteria for quality, there are many problems with CPGs, including many of those that the GAC has favourably evaluated. First, there is strong evidence that guidelines are not developed according to stringent criteria. Shaneyfelt has demonstrated that “Guidelines published in the peer-reviewed medical literature during the past decade do not adhere well to established methodological standards. While all areas of guideline development need improvement, greatest improvement is needed in the identification, evaluation, and synthesis of the scientific evidence.”7 Second, guidelines follow the clinical research paradigm and are often developed with only one condition or disease in mind. Patients seen by family physicians usually present with several chronic and interacting conditions, making the application of guideline recommendations more difficult.8 Third, guidelines often do not take into account patient preferences for care, something that family physicians are explicitly trained to do. Fourth, even high-quality guidelines fall short in the way they are disseminated to family physicians. Guidelines are usually passively distributed by mail and in paper form. Although there are increasing exceptions, they also tend to be long, detailed, and do not provide specific clinically useful summaries for busy doctors.9

Improving guidelines

Is there a way to improve CPGs and to reduce the enormous time pressures that burgeoning guidelines place on family physicians? I believe that the answer is yes, but several changes in current practice and in the way that guidelines are developed and disseminated are necessary.

Guidelines need to be “done” differently. Guideline panels typically consist of large numbers of specialist content experts with 2 or 3 family physicians included. Having sat on a guideline panel in the past,10 I can reflect that much of the discussion over 2 days was about research evidence to support the recommendations. While this discussion is critically important, very little time was spent on the equally important issue of dissemination (or knowledge translation). This is a world turned upside down. I propose that guideline panels of the future have much greater representation from family physicians working in different settings, with a small number of content experts to advise them on content. In that way, perhaps, greater attention will be paid to how family physicians can use the guidelines in their practices.

Greater emphasis needs to be placed on applying guidelines to the type of patients seen in family practice settings—the elderly and those with multiple chronic conditions. Furthermore, greater attention needs to be placed on the evidence for the effectiveness of interventions in guidelines. Family physicians are swamped with maneuvers supported only by expert opinion.

This has been said and written many times before, but more attention needs to be paid to the effective dissemination and implementation of good guidelines. Stronger input from family physicians is crucial if dissemination is to be successful.

As family physicians move toward working in family health teams or groups that incorporate and integrate other health care professionals, greater attention needs to be paid to the role of other providers in the delivery of acute, chronic, and preventive care. Clearly, if family physicians are to continue to provide high-quality care and incorporate guideline recommendations into their practices, they will need to share this work with other professionals. Many preventive care maneuvers can be performed, for example, by nurse practitioners integrated into family health teams. Similarly, nurse practitioners can effectively provide care for some chronic conditions, allowing family physicians to focus on acute care or on patients with chronic illnesses that are unstable.

Family physicians are under increasing time pressures to provide both preventive and chronic illness care. The growth in CPGs for both preventive and chronic care and the expectation that they will be closely followed by family physicians has contributed substantially to the time pressures. Improvements in the quality and in the dissemination of guidelines and the integration of other health care providers, such as nurse practitioners, into family health teams could help ease time pressures on family physicians and improve the quality of their work lives.

Footnotes

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

References

  1. Bodenheimer T. Primary care—will it survive? New Engl J Med 2006;355:861-4.[Free Full Text]
  2. Yarnall KS, Pollak KI, Østbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-41.[Abstract/Free Full Text]
  3. Østbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-14.[Abstract/Free Full Text]
  4. Gilchrist V, McCord G, Schrop SL, King BD, McCormick KF, Oprandi AM, et al. Physician activities during time out of the examination room. Ann Fam Med 2005;3:494-9.[Abstract/Free Full Text]
  5. Gottschalk A, Flocke SA. Time spent in face-to-face patient care and work outside the examination room. Ann Fam Med 2005;3:488-93.[Abstract/Free Full Text]
  6. Slade S, Busing N. Weekly work hours and clinical activities of Canadian family physicians: results of the 1997–98 National Family Physician Survey of the College of Family Physicians of Canada. CMAJ 2002;166:1407-11.[Abstract/Free Full Text]
  7. Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature. JAMA 1999;281:1900-5.[Abstract/Free Full Text]
  8. Upshur RE. The complex, the exhausted and the personal: reflections on the relationship between evidence-based medicine and casuistry. Commentary on Tonelli (2006), Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12(3):281-8.[Medline]
  9. Michie S, Johnston M. Changing clinical behaviour by making guidelines specific. BMJ 2004;328:343-5.[Free Full Text]
  10. Ontario Ministry of Health and Long-Term Care. Ontario guidelines for the prevention and treatment of osteoporosis. Ontario Program for Optimal Therapeutics. Toronto, ON: Ontario Ministry of Health and Long-Term Care; 2000. Available from: www.opot.org/guidelines/osteoporosis.pdf. Accessed 2007 November 27.

Who has time for family medicine?

Nicholas Pimlott, MD CCFP
Associate Professor in the Department of Family and Community Medicine at the University of Toronto, Research Director of the Family Practice Health Centre at Women’s College Hospital in Toronto, Ont., and Associate Editor of Canadian Family Physician

Correspondence to: Dr Nicholas Pimlott, 60 Grosvenor St, Toronto, ON M5S 1B6; telephone 416 323–6065; fax 416 323–6335; e-mail nick.pimlott@utoronto.ca<!– var u = "nick.pimlott", d = "utoronto.ca"; document.getElementById("em0").innerHTML = '‘ + u + ‘@’ + d + ”//–>

Recently a number of articles in the medical literature have discussed the many dissatisfactions of primary care physicians, including family physicians.

Bodenheimer1 has clearly documented the growing pressures on primary care physicians in the United States. Patients are dissatisfied as they experience longer wait times and perceive the quality of care they receive to be inadequate. Physicians are dissatisfied because they feel they are paid for volume, not quality; they earn half the income of specialists and the gap is widening; and they find that the workload is becoming impossible to sustain. The situation is similar in Canadian primary care.

Time pressures

The first published evidence examining family physician workload appeared in 2003. Yarnall et al2 used published and estimated times per service to determine the physician time required to provide all of the services recommended by the US Preventive Services Task Force, at the recommended frequency, to a patient panel of 2500 with an age and sex distribution similar to that of the US population. They found that to fully satisfy the US Preventive Services Task Force recommendations, a physician would have to spend 1773 hours per year, or 7.4 hours per working day, providing preventive services.

Recently, using similar methods, Østbye et al3 applied guideline recommendations for 10 common chronic diseases to a panel of 2500 primary care patients (with an age and sex distribution and chronic disease prevalence similar to those of the general population) and estimated the minimum physician time required to deliver high-quality care for these conditions. The result was compared with time available for patient care for the average primary care physician. They found that 823 hours per year, or 3.5 hours a day, were required to provide care for the 10 most common chronic diseases, provided the diseases were stable and in good control. They recalculated this estimate based on increased time requirements for uncontrolled disease. The estimated time required increased by a factor of 3. Applying this factor to all 10 diseases, time demands increased to 2484 hours per year or 10.6 hours a day. The authors concluded that meeting current practice guidelines for only 10 chronic illnesses requires more time than primary care physicians have available for patient care overall.

When we combine the results of these 2 studies, the average American family physician will spend between 10.9 and 18 hours per day delivering preventive and chronic illness care. Such estimates fail to account for time spent in the delivery of acute care for common conditions, such as upper respiratory tract infections and urinary tract infections, that make up much of a typical day. They also fail to account for time spent outside the examination room answering telephone calls, filling out forms, making referrals, and so on, which takes up a substantial part of the day.4,5

The situation begs some obvious questions. How did expectations for family physicians outstrip the number of hours in the day? Since even the most conscientious family physician is not working 24 hours a day,6 how do family physicians cope with such expectations and demands on their time? Finally, how can expectations of family physicians be made more realistic without compromising the quality of patient care?

Guideline explosion

Several factors have contributed to the time crunch for family physicians, but I believe one factor in particular has had an enormous effect—the explosion of clinical practice guidelines (CPGs) over the past decade. Clinical practice guidelines emerged in the 1970s in most of the industrialized world, beginning with the Canadian Task Force on the Periodic Health Examination in Canada and the US Preventive Services Task Force in the United States. The task forces had an admirable purpose and necessary goals: to evaluate the scientific evidence behind preventive care and to make evidence-based recommendations for practice. These task forces established clear evidence hierarchies and a clear process for the evaluation and the dissemination of clinical evidence. Their recommendations continue to guide primary preventive care today.

Since that time there has been an explosion of CPGs aimed at family physicians. There are more than 2000 guidelines available from the website of the National Guidelines Clearinghouse (www.guideline.gov) in the United States (although not all of them are relevant to family physicians). At last count there were 124 CPGs posted on the website (http://gacguidelines.ca) of the Ontario-based Guidelines Advisory Committee (GAC), an organization dedicated to the evaluation and dissemination of guidelines relevant to family physicians; the GAC’s mission is “to promote better health for the people of Ontario by encouraging physicians and other practitioners to use evidence-based clinical practice guidelines and clinical practices based on best available evidence. In particular, to increase awareness and use of best available evidence, [they] identify, evaluate, endorse and summarize guidelines for use in Ontario.”

While the GAC evaluates and rates CPGs according to criteria for quality, there are many problems with CPGs, including many of those that the GAC has favourably evaluated. First, there is strong evidence that guidelines are not developed according to stringent criteria. Shaneyfelt has demonstrated that “Guidelines published in the peer-reviewed medical literature during the past decade do not adhere well to established methodological standards. While all areas of guideline development need improvement, greatest improvement is needed in the identification, evaluation, and synthesis of the scientific evidence.”7 Second, guidelines follow the clinical research paradigm and are often developed with only one condition or disease in mind. Patients seen by family physicians usually present with several chronic and interacting conditions, making the application of guideline recommendations more difficult.8 Third, guidelines often do not take into account patient preferences for care, something that family physicians are explicitly trained to do. Fourth, even high-quality guidelines fall short in the way they are disseminated to family physicians. Guidelines are usually passively distributed by mail and in paper form. Although there are increasing exceptions, they also tend to be long, detailed, and do not provide specific clinically useful summaries for busy doctors.9

Improving guidelines

Is there a way to improve CPGs and to reduce the enormous time pressures that burgeoning guidelines place on family physicians? I believe that the answer is yes, but several changes in current practice and in the way that guidelines are developed and disseminated are necessary.

Guidelines need to be “done” differently. Guideline panels typically consist of large numbers of specialist content experts with 2 or 3 family physicians included. Having sat on a guideline panel in the past,10 I can reflect that much of the discussion over 2 days was about research evidence to support the recommendations. While this discussion is critically important, very little time was spent on the equally important issue of dissemination (or knowledge translation). This is a world turned upside down. I propose that guideline panels of the future have much greater representation from family physicians working in different settings, with a small number of content experts to advise them on content. In that way, perhaps, greater attention will be paid to how family physicians can use the guidelines in their practices.

Greater emphasis needs to be placed on applying guidelines to the type of patients seen in family practice settings—the elderly and those with multiple chronic conditions. Furthermore, greater attention needs to be placed on the evidence for the effectiveness of interventions in guidelines. Family physicians are swamped with maneuvers supported only by expert opinion.

This has been said and written many times before, but more attention needs to be paid to the effective dissemination and implementation of good guidelines. Stronger input from family physicians is crucial if dissemination is to be successful.

As family physicians move toward working in family health teams or groups that incorporate and integrate other health care professionals, greater attention needs to be paid to the role of other providers in the delivery of acute, chronic, and preventive care. Clearly, if family physicians are to continue to provide high-quality care and incorporate guideline recommendations into their practices, they will need to share this work with other professionals. Many preventive care maneuvers can be performed, for example, by nurse practitioners integrated into family health teams. Similarly, nurse practitioners can effectively provide care for some chronic conditions, allowing family physicians to focus on acute care or on patients with chronic illnesses that are unstable.

Family physicians are under increasing time pressures to provide both preventive and chronic illness care. The growth in CPGs for both preventive and chronic care and the expectation that they will be closely followed by family physicians has contributed substantially to the time pressures. Improvements in the quality and in the dissemination of guidelines and the integration of other health care providers, such as nurse practitioners, into family health teams could help ease time pressures on family physicians and improve the quality of their work lives.

Footnotes

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

References

  1. Bodenheimer T. Primary care—will it survive? New Engl J Med 2006;355:861-4.[Free Full Text]
  2. Yarnall KS, Pollak KI, Østbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-41.[Abstract/Free Full Text]
  3. Østbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-14.[Abstract/Free Full Text]
  4. Gilchrist V, McCord G, Schrop SL, King BD, McCormick KF, Oprandi AM, et al. Physician activities during time out of the examination room. Ann Fam Med 2005;3:494-9.[Abstract/Free Full Text]
  5. Gottschalk A, Flocke SA. Time spent in face-to-face patient care and work outside the examination room. Ann Fam Med 2005;3:488-93.[Abstract/Free Full Text]
  6. Slade S, Busing N. Weekly work hours and clinical activities of Canadian family physicians: results of the 1997–98 National Family Physician Survey of the College of Family Physicians of Canada. CMAJ 2002;166:1407-11.[Abstract/Free Full Text]
  7. Shaneyfelt TM, Mayo-Smith MF, Rothwangl J. Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature. JAMA 1999;281:1900-5.[Abstract/Free Full Text]
  8. Upshur RE. The complex, the exhausted and the personal: reflections on the relationship between evidence-based medicine and casuistry. Commentary on Tonelli (2006), Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12(3):281-8.[Medline]
  9. Michie S, Johnston M. Changing clinical behaviour by making guidelines specific. BMJ 2004;328:343-5.[Free Full Text]
  10. Ontario Ministry of Health and Long-Term Care. Ontario guidelines for the prevention and treatment of osteoporosis. Ontario Program for Optimal Therapeutics. Toronto, ON: Ontario Ministry of Health and Long-Term Care; 2000. Available from: www.opot.org/guidelines/osteoporosis.pdf. Accessed 2007 November 27.

http://www.cfp.ca/cgi/content/full/54/1/14

Una vacuna con demasiadas dudas


Más allá de anuncios rimbombantes, faltan años para demostrar que la inmunización contra el HPV es efectiva y segura. <!–
Relac: 3–><!–
Multi: 0–>

Josefina Edelstein – La Voz del Interior
Especial

Si bien las vacunas han puesto a salvo a la humanidad de numerosas enfermedades, y desde hace tiempo la expectativa de buena parte de la población mundial está puesta en la obtención de un medicamento preventivo para el cáncer, médicos y científicos recomiendan tener cautela respecto de la promocionada vacuna contra el virus del papiloma humano (HPV por sus siglas en inglés).

Desde Estados Unidos, Canadá y Europa piden mesura y racionalidad a los gobiernos antes de indicar la vacunación en niñas de 12 años y mucho más, cuando se plantean incluirla en el calendario oficial para inmunizar masivamente, aunque muchos países, presionados por los laboratorios fabricantes, ya la incorporaron.

La vacuna fue desarrollada para evitar la infección con los virus 16 y 18 del HPV y los ensayos clínicos han demostrado su efectividad, durante cinco a seis años y medio, en la reducción de lesiones precancerosas producidas por estas cepas. Básicamente, ésta es una de las pocas certezas científicas hasta el momento, mientras que el impacto real de la vacuna se conocerá al cabo de décadas.

Los reparos que esgrime desde hace tiempo la comunidad científica están planteados en un artículo y editorial que publicó –nada menos– que el New England Journal of Medicine, el 21 de agosto último.

Los cuestionamientos giran en torno a respuestas que requieren años de estudio y seguimiento:

No existen evidencias científicas de que la vacuna pueda prevenir el cáncer de cuello uterino y tampoco la mortalidad.

No se sabe cuánto tiempo durará su protección y, por lo tanto, se desconoce si será necesario aplicar un refuerzo.

El sistema inmunológico elimina en forma natural el 90 por ciento de las infecciones por HPV y no hay datos que muestren que este proceso no se alterará con la vacunación.

Por lo mismo, se teme un posible efecto de “nicho vacío”, ya que la vacuna que “evita la presencia o actividad de los virus contra los que protege”, al mismo tiempo podría “cambiar la ecología del cuello uterino y alrededores y permitir la proliferación de otros virus de alto riesgo oncológico, o la transformación de los de bajo riesgo”, explica Juan Gérvas, médico español y profesor en la Escuela Nacional de Sanidad y en la Universidad Autónoma de Madrid, quien en 2007 escribió el artículo “La incierta prevención del cáncer de cuello de útero con la vacuna contra el Virus del Papiloma Humano”.

Los resultados de los ensayos clínicos se han obtenido con mujeres de 16 a 24 años, de manera que no se sabe cómo reaccionará el organismo de las chicas de 12 años a quienes se pretende inmunizar.

La vacuna protege de la infección de dos de los tipos (16 y 18) de HPV que se encuentran en el 70 por ciento de los casos de cáncer de cérvix, pero existen 15 cepas oncogénicas. Esto lleva a pensar que las mujeres que se vacunen podrían relajarse en cuanto al control con Papanicolau que, de todos modos, se deben realizar anualmente para detectar posibles lesiones cancerígenas.

Presión farmacéutica. Para el marketing existe la premisa de que las necesidades de consumo se crean y nada mejor que instalar temor para correr a calmarlo.

La arrolladora campaña de promoción de Merck para su vacuna Gardasil y, en menor medida, la de GlaxoSmithKline para su versión llamada Cervarix, también han sido foco de críticas y están descriptas en detalle en el artículo que publicó el prestigioso periódico The New York Times, el 20 del mes pasado. A través de los medios de comunicación, los laboratorios posicionaron al HPV como que está a la vuelta de la esquina e instalaron una sensación generalizada de temor hacia el cáncer.

Los laboratorios también “sensibilizaron” sobre el tema aportando dinero a médicos, organizaciones de padres, de mujeres, de pacientes, a sociedades científicas, organismos estatales y haciendo lobby en grupos políticos. El periódico informa que en Estados Unidos Merck convocó a cientos de médicos y enfermeras y los entrenó para que den charlas sobre la vacuna y por cada disertación se les pagó 4.500 dólares, nada más.

“Hubo una presión increíble de la industria y los políticos”, dijo Jon Abramson, ex presidente del Comité de los Centros de Control y Prevención de Enfermedades de Estados Unidos.

Por su parte, Abby Lippman, directora de la Red de Salud de Mujeres Canadienses, expresó que el agresivo marketing “está enloqueciendo a las mujeres que piensan que son malas madres si no hacen vacunar a sus hijas”.

Otra voz que da cuenta de la presión farmacéutica es la de Diane Harper, quien se desempeñó como investigadora principal de los ensayos clínicos de Gardasil y Cervarix: “Merck hizo lobby en cada líder de opinión, grupo de mujeres, sociedad médica, políticos y apuntó directo a la gente, creando una sensación de pánico que lleva a la necesidad de tener que estar vacunado ya”.

El médico español Juan Gérvas expresa en su artículo que “está demostrada su ineficacia en mujeres no vírgenes”. Consultado vía correo electrónico, explica que “si hubo actividad sexual previa es absurdo vacunar, porque la mayoría de las mujeres ya se ha contagiado con el virus y también la mayoría ´se limpian´ por sí mismas y crean inmunidad celular, por lo tanto la vacuna es inútil”.

El tiempo dirá. En este escenario, ¿vale la pena que se vacunen niñas y mujeres? Más aun, ¿tiene sentido incluir la vacuna contra el HPV en el calendario oficial, como se viene intentando por algunas vías en el Congreso Nacional o en algunas legislaturas provinciales?

En la Argentina, sólo el 20 por ciento de las mujeres se hace el control de Papanicolau, entre otras razones, porque “las chicas no tienen incorporado el hábito de hacerse controles y los servicios de salud están abarrotados”, señala la especialista en adolescentes Juana Presman.

La Administración Nacional de Medicamentos, Alimentos y Tecnología Médica (Anmat) autorizó una de las vacunas para mujeres de 9 a 26 años y la otra para las de 10 a 45 años.

El costo de la vacuna tetravalente (Gardasil) es de 926,48 pesos por dosis y son necesarias tres; mientras que la fórmula bivalente (Cervarix) se vende a 384 pesos y también hay que multiplicarlos por tres. Son cifras altas para el bolsillo de la gente y para el presupuesto de salud estatal. Aun más cuando faltan certezas sobre su efectividad y seguridad.

Una vacuna con demasiadas dudas


Más allá de anuncios rimbombantes, faltan años para demostrar que la inmunización contra el HPV es efectiva y segura. <!–
Relac: 3–><!–
Multi: 0–>

Josefina Edelstein – La Voz del Interior
Especial

Si bien las vacunas han puesto a salvo a la humanidad de numerosas enfermedades, y desde hace tiempo la expectativa de buena parte de la población mundial está puesta en la obtención de un medicamento preventivo para el cáncer, médicos y científicos recomiendan tener cautela respecto de la promocionada vacuna contra el virus del papiloma humano (HPV por sus siglas en inglés).

Desde Estados Unidos, Canadá y Europa piden mesura y racionalidad a los gobiernos antes de indicar la vacunación en niñas de 12 años y mucho más, cuando se plantean incluirla en el calendario oficial para inmunizar masivamente, aunque muchos países, presionados por los laboratorios fabricantes, ya la incorporaron.

La vacuna fue desarrollada para evitar la infección con los virus 16 y 18 del HPV y los ensayos clínicos han demostrado su efectividad, durante cinco a seis años y medio, en la reducción de lesiones precancerosas producidas por estas cepas. Básicamente, ésta es una de las pocas certezas científicas hasta el momento, mientras que el impacto real de la vacuna se conocerá al cabo de décadas.

Los reparos que esgrime desde hace tiempo la comunidad científica están planteados en un artículo y editorial que publicó –nada menos– que el New England Journal of Medicine, el 21 de agosto último.

Los cuestionamientos giran en torno a respuestas que requieren años de estudio y seguimiento:

No existen evidencias científicas de que la vacuna pueda prevenir el cáncer de cuello uterino y tampoco la mortalidad.

No se sabe cuánto tiempo durará su protección y, por lo tanto, se desconoce si será necesario aplicar un refuerzo.

El sistema inmunológico elimina en forma natural el 90 por ciento de las infecciones por HPV y no hay datos que muestren que este proceso no se alterará con la vacunación.

Por lo mismo, se teme un posible efecto de “nicho vacío”, ya que la vacuna que “evita la presencia o actividad de los virus contra los que protege”, al mismo tiempo podría “cambiar la ecología del cuello uterino y alrededores y permitir la proliferación de otros virus de alto riesgo oncológico, o la transformación de los de bajo riesgo”, explica Juan Gérvas, médico español y profesor en la Escuela Nacional de Sanidad y en la Universidad Autónoma de Madrid, quien en 2007 escribió el artículo “La incierta prevención del cáncer de cuello de útero con la vacuna contra el Virus del Papiloma Humano”.

Los resultados de los ensayos clínicos se han obtenido con mujeres de 16 a 24 años, de manera que no se sabe cómo reaccionará el organismo de las chicas de 12 años a quienes se pretende inmunizar.

La vacuna protege de la infección de dos de los tipos (16 y 18) de HPV que se encuentran en el 70 por ciento de los casos de cáncer de cérvix, pero existen 15 cepas oncogénicas. Esto lleva a pensar que las mujeres que se vacunen podrían relajarse en cuanto al control con Papanicolau que, de todos modos, se deben realizar anualmente para detectar posibles lesiones cancerígenas.

Presión farmacéutica. Para el marketing existe la premisa de que las necesidades de consumo se crean y nada mejor que instalar temor para correr a calmarlo.

La arrolladora campaña de promoción de Merck para su vacuna Gardasil y, en menor medida, la de GlaxoSmithKline para su versión llamada Cervarix, también han sido foco de críticas y están descriptas en detalle en el artículo que publicó el prestigioso periódico The New York Times, el 20 del mes pasado. A través de los medios de comunicación, los laboratorios posicionaron al HPV como que está a la vuelta de la esquina e instalaron una sensación generalizada de temor hacia el cáncer.

Los laboratorios también “sensibilizaron” sobre el tema aportando dinero a médicos, organizaciones de padres, de mujeres, de pacientes, a sociedades científicas, organismos estatales y haciendo lobby en grupos políticos. El periódico informa que en Estados Unidos Merck convocó a cientos de médicos y enfermeras y los entrenó para que den charlas sobre la vacuna y por cada disertación se les pagó 4.500 dólares, nada más.

“Hubo una presión increíble de la industria y los políticos”, dijo Jon Abramson, ex presidente del Comité de los Centros de Control y Prevención de Enfermedades de Estados Unidos.

Por su parte, Abby Lippman, directora de la Red de Salud de Mujeres Canadienses, expresó que el agresivo marketing “está enloqueciendo a las mujeres que piensan que son malas madres si no hacen vacunar a sus hijas”.

Otra voz que da cuenta de la presión farmacéutica es la de Diane Harper, quien se desempeñó como investigadora principal de los ensayos clínicos de Gardasil y Cervarix: “Merck hizo lobby en cada líder de opinión, grupo de mujeres, sociedad médica, políticos y apuntó directo a la gente, creando una sensación de pánico que lleva a la necesidad de tener que estar vacunado ya”.

El médico español Juan Gérvas expresa en su artículo que “está demostrada su ineficacia en mujeres no vírgenes”. Consultado vía correo electrónico, explica que “si hubo actividad sexual previa es absurdo vacunar, porque la mayoría de las mujeres ya se ha contagiado con el virus y también la mayoría ´se limpian´ por sí mismas y crean inmunidad celular, por lo tanto la vacuna es inútil”.

El tiempo dirá. En este escenario, ¿vale la pena que se vacunen niñas y mujeres? Más aun, ¿tiene sentido incluir la vacuna contra el HPV en el calendario oficial, como se viene intentando por algunas vías en el Congreso Nacional o en algunas legislaturas provinciales?

En la Argentina, sólo el 20 por ciento de las mujeres se hace el control de Papanicolau, entre otras razones, porque “las chicas no tienen incorporado el hábito de hacerse controles y los servicios de salud están abarrotados”, señala la especialista en adolescentes Juana Presman.

La Administración Nacional de Medicamentos, Alimentos y Tecnología Médica (Anmat) autorizó una de las vacunas para mujeres de 9 a 26 años y la otra para las de 10 a 45 años.

El costo de la vacuna tetravalente (Gardasil) es de 926,48 pesos por dosis y son necesarias tres; mientras que la fórmula bivalente (Cervarix) se vende a 384 pesos y también hay que multiplicarlos por tres. Son cifras altas para el bolsillo de la gente y para el presupuesto de salud estatal. Aun más cuando faltan certezas sobre su efectividad y seguridad.

El concepto de prevencion


The concept of prevention: a good idea gone astray?

B Starfield1, J Hyde2,3, J Gérvas4,5, I Heath6

1 Johns Hopkins University, Baltimore, MD, USA
2 Victoria Department of Human Services, Melbourne, Australia
3 Monash University, Melbourne, Australia
4 Equipo CESCA, Madrid, Spain
5 Canencia de la Sierra (Madrid), Spain
6 Caversham Group Practice, London, UK

Correspondence to:
Dr B Starfield, Professor of Health Policy, 624 N Broadway, room 452, Johns Hopkins University, Baltimore, MD 21205-1990, USA; bstarfie@jhsph.edu

Over time, the definition of prevention has expanded so that its meaning in the context of health services is now unclear. As risk factors are increasingly considered to be the equivalent of “diseases” for purposes of intervention, the concept of prevention has lost all practical meaning. This paper reviews the inconsistencies in its utility, and suggests principles that it should follow in the future: a population orientation with explicit consideration of attributable risk, the setting of priorities based on reduction in illness and avoidance of adverse effects, and the imperative to reduce inequities in health.

Texto completo en PDF

El concepto de prevencion


The concept of prevention: a good idea gone astray?

B Starfield1, J Hyde2,3, J Gérvas4,5, I Heath6

1 Johns Hopkins University, Baltimore, MD, USA
2 Victoria Department of Human Services, Melbourne, Australia
3 Monash University, Melbourne, Australia
4 Equipo CESCA, Madrid, Spain
5 Canencia de la Sierra (Madrid), Spain
6 Caversham Group Practice, London, UK

Correspondence to:
Dr B Starfield, Professor of Health Policy, 624 N Broadway, room 452, Johns Hopkins University, Baltimore, MD 21205-1990, USA; bstarfie@jhsph.edu

Over time, the definition of prevention has expanded so that its meaning in the context of health services is now unclear. As risk factors are increasingly considered to be the equivalent of “diseases” for purposes of intervention, the concept of prevention has lost all practical meaning. This paper reviews the inconsistencies in its utility, and suggests principles that it should follow in the future: a population orientation with explicit consideration of attributable risk, the setting of priorities based on reduction in illness and avoidance of adverse effects, and the imperative to reduce inequities in health.

Texto completo en PDF

El concepto de prevencion


Otro excelente articulo de Juan Gervas y Barbara Starfield….. el texto completo fue provisto por Ana Carolina Diaz Oliveira. 

Over time, the definition of prevention has expanded so that its meaning in the context of health services is now unclear. As risk factors are increasingly considered to be the equivalent of “diseases” for purposes of intervention, the concept of prevention has lost all practical meaning. This paper reviews the inconsistencies in its utility, and suggests principles that it should follow in the future: a population orientation with explicit consideration of attributable risk, the setting of priorities based on reduction in illness and avoidance of adverse effects, and the imperative to reduce inequities in health.

The scope of prevention has changed over time. A 1967 textbook stated: “Prevention, in a narrow sense, means averting the development of a pathological state. In a broader sense, it includes all measures—definitive therapy among them—that limit the progression of disease at any stage of its course”.1 A distinction was made between interventions that avert the occurrence of disease (primary prevention) and interventions that halt or slow the progression of a disease or its sequelae at any point after its inception (secondary prevention).

By 1978, the distinctions between types of prevention had expanded to include primary prevention to promote health prior to the development of disease or injuries; secondary prevention to detect disease in early (asymptomatic) stages; and tertiary prevention to reverse, arrest or delay progression of disease.2

Neither the 1967 nor the 1978 definitions used the terminology of “risk factor”, but in 1998, the World Health Organization, in addressing “disease” prevention, stated that it “covers measures not only to prevent the occurrence of disease, such as risk factor reduction, but also to arrest its progress and reduce its consequences once established”. The Australian National Public Health Partnership designated prevention as “action to reduce or eliminate or reduce the onset, causes, complications, or recurrence of disease”.3 Several levels were defined: primordial prevention (“preventing the emergence of predisposing social and environmental conditions that can lead to causation of disease;primary prevention; secondary prevention; and tertiary prevention to improve function, minimise impact, and delay complications”).

The Dictionary of Public Health defined prevention similarly, but conceded that the distinction between levels “is more artificial than real”.4

A recent addition to the lexicon of prevention is “quaternary prevention”. The world organisation of family physicians (WONCA) defined quaternary prevention as “an action taken to identify a patient at risk of over-medicalization, to protect him (sic) from new medical invasion, and to suggest to him (sic) interventions which are ethically acceptable”.5 Gofrit et al. defined quaternary prevention as “debriefing, quality assurance, and improvement processes”, which “complete the cycle of prevention by collecting information about the processes, multi-disciplinary analysis of the data, deriving conclusions, and distributing them to all the involved bodies”.6

Quaternary prevention has also been defined by cardiovascular disease experts as “rehabilitation or restoration of function”, applicable to “those with severe cardiovascular dysfuntion”.7 These three definitions are not easily compatible.

Identification of “risk factors” as part of prevention has been designated a new era in public health and clinical medicine8 and as a new professional activity of epidemiologists.9 10 Risk factors, such as elevated blood pressure, are now even considered as “diseases”.11

The shift from public health to clinical disease is evident in the historical development of the concept of prevention. Geoffrey Rose provided the basis for a population orientation to reducing risk factors associated with coronary heart disease, arguing that only a small proportion of cardiovascular events occur in individuals with high risk scores. He maintained that population-based prevention must be low cost, minimally invasive and avoid discomfort and pain. His arguments have been used in ways never intended: to justify treatment of individuals in clinical settings.12 This reflects the emergence of the concept of “preventive medicine”, particularly in the US. Clinical medicine, while increasingly adopting prevention as a field of activity, lacks a definition of prevention: the Guide to Clinical Preventive Services (US Task Force on Prevention) does not offer one despite increasing confusion about the boundaries between the different levels of prevention. The World Health Organization did not include the term “prevention” as a function of health systems, which are defined as “all the activities whose primary purpose is to promote, restore, and maintain health”.13

Is the concept of “prevention”, with its increasing focus on particular diseases and risk factors (rather than on ill health in general), still useful? When so many people lack adequate access to medical care for their manifest health needs, is it justifiable that routine disease check-up visits are approaching half of all medical visits, as in the United States?1416 Is intervention with four drugs, lifestyle advice and cardiacrehabilitation really prevention, as suggested by the title of a published study “Secondary prevention for patients after a myocardial infarction: summary of NICE guidelines”?17 Is intervention to reduce the blood level of a known “risk factor” (eg homocysteine) really prevention when it does not reduce the occurrence of the disease or improve overall health?18 Should controlling risk factors replace the conventional focus on controlling disease, even if it does not necessarily improve health? Should medication (eg cerivastatin) to improve surrogate outcomes in cardiovascular trials19 20 be considered “prevention” when its use is associated with fatal rhabdomyolisis causing it to be withdrawn from theworld market?21 Is it time for a new formulation?

As a result of marked changes in the organsation of health services and increases in knowledge about the genesis and management of disease, there is good reason to question the differentiation of prevention from other aspects of health care.

Clinical settings are increasingly moving towards population-based medicine. As clinical practices become larger, with defined populations, the realities of individual-based medical care now have to confront the principles of population-based care. Increased risk of an event based upon the presence of a “predisposing factor” with high relative risk may no longer be the main criterion for intervention. The “event” may be too uncommon in the population and hence not practical as a priority. Alternatively, the intervention to reduce excess risk, while useful based on statistical associations in clinical trials, may not be useful in other population groups not included in the trial.22 A prime example is the utility of statins for “prevention” of recurrent myocardial infarct in men and the absence of evidence for their utility in either primary or secondary prevention in women.23 The presence of sex differences in screening for abdominal aortic aneurysm provides another example; screening might be useful in at least some men but is not useful in women.24 Clinical trials might not identify population group differences as most, by virtue of their design, are unable to examine the range of individual and community characteristics that could influence responsiveness to interventions.

A preventive activity might be justified in one setting but not in another just because of differences in prevalence, even though the relative risk based on the exposure is the same. What works in one clinical setting may not work in another, even when the relative risk of a characteristic is the same. Population-based studies of the predictive value of exposures consistently find lower likelihood of disease in the presence of a risk factor than do clinically based studies.25 26 As clinical settings are becoming more and more population based, policies regarding the utility of preventive measures are likely to require change.

Perhaps the biggest threat to the concept of prevention, however, is the progressive lowering of thresholds for “predisease”, particularly hypertension, serum cholesterol and blood sugar. With current thresholds, 97% of all US adults aged 50 and over have one or more of these three risk factors, but only 8% of cardiovascular disease will occur in individuals with any combination of them. The United States Preventive Services Task Force (USPSTF) has yet to update its recommendations for people with the changed definition of these conditions.12Encouraged by interests vested in selling more medications for “prevention” and more medical devices for testing, the pressure for increasing “prevention” in clinical care directed at individuals is inexorable—even though it is not well supported by evidence in populations of patients.27

The focus of prevention has always been on “diseases”. As the concept of “disease” is changing over time (with lowering thresholds for designation of “disease”)28 and risk factors are considered equivalent to disease, the boundaries between prevention and cure are becoming increasingly indistinct. Physicians, as a profession, have always had the power to define “diseases” and stages of diseases.29 30 For example, the current definition of heart failure31 includes four stages. Obesity constitutes stage A, even in the absence of symptoms or structural changes in the heart. Stage B also constitutes being “at risk of heart failure”. Only stages C and D constitute evident heart failure.States A and B are preheart failure – a “diagnosis” justifying medication. When drugs are promoted for prevention and the number of patients at risk is very large, the expanded exposure to the drug may lead to important harm.32 The increasing attention to iatrogenic causes of ill health and the resulting addition of “quaternary prevention” also point to the need to explicitly include iatrogenesis as an influence on ill health.

Recommendations for clinical preventive services still focus largely on the results of analyses of relative risk in individuals not necessarily representative of the population or subpopulations.33 Furthermore, recommendations for risk factor screening are made one by one, despite evidence that risk factors are not independent of each other. On average, adult patients in the US in the mid-1990s were estimated to have approximately 12 risk factors requiring approximately 24 preventive services—even before the explosion of the concept of risks.34 A more recent analysis, recognising some of the limitations of estimates of benefit, set several priorities for clinical prevention in the total population based on “preventable burden” and cost-effectiveness; none involved medications other than immunisations.35

The major challenges in setting policy for interventions to reduce illness seem to be:

  1. avoiding the fallacy that risks are independent 
  2. the importance of setting priorities based upon frequency of the desired outcome in populations 
  3. the importance of setting priorities to reduce inequities in health in populations as well as or in preference to improving effectiveness in individuals 
  4. considering when it is more efficient (and perhaps more effective and equitable) to prioritise interventions to populations, includingdefined populations in the clinical sector 
  5. placing priority on improving health generically (as, for example, by reduction in overall and age-specific death rates, by improvementsin life expectancy and by reductions in disability and in perceived poor health) rather than disease by disease33 36 37 
  6. taking into account the patient’s perspective in clinical prevention38 
  7. avoiding incentives for physician activities that are measurable but of low priority for population health gain.39 

A framework (table 1) for conceptualising reductions in the occurrence and severity and progression of disease would both abandon the confusing and outmoded approach to prevention and substitute a framework that distinguishes societal from individual interventions on the one hand and, on the other, distinguishes risks that result from suboptimal physical, social, health service and individual environments.

View this table:
[in this window]
[in a new window]

 

Table 1 Levels and types of interventions to improve health*

 
The increasing world focus on achieving equity in health40 is likely to bring greater pressure on advocates of “prevention” to more clearly delineate the scope of the concept and the nature of ameliorative efforts. If inequities in health are to be reduced or eliminated, the full range of possible interventions needs to be specified and choices made about priorities. The “web” of influences on health and on inequity in health is very broad, ranging from societal influences to policy influences, to community influences, to social relationships and to individual characteristics (innate as well as developmental, biological and behavioural).41 The possibilities for prevention are vast, involving very differenttypes of approaches and constituencies because prevention involves virtually every sector of societal, social and individual endeavour.

It would be presumptuous to suggest that the term “prevention”, which is so widely entrenched in medical thinking and supported by committed constituencies, could be discarded even if its vagueness is largely dysfunctional. It may be possible, however, to seek agreement on two critical aspects: a focus on population health and a focus on reducing disparities (inequities) in health.

“Population based” is no longer synonymous with “public health”. Public health constitutes societal approaches to improving health, but “population based” means that evidence is derived from population statistics rather than from individual patients in unrepresentative clinical practice. Priorities for action are made on the basis of population-based evidence, which includes consideration of attributable risk as well as relative risk. The hazards of clinical prevention have been catalogued42 and include such considerations as absence of evidence relevant to setting priorities and imprecision of rules allowing prediction of benefit; competition of clinical preventive activities with care of manifest problems; and compromised health resulting from preventive interventions. In view of the systematic dismantling of the public health infrastructure in at least some countries with concomitant increases in the scope and influence of clinical services, an adoption of populationprinciples for clinical services would appear to be in order.

A fresh approach to prevention requires a refocusing of attention from evidence relevant to individuals to evidence relevant to populations—even those in clinical settings. Preventive activities have widely differing effectiveness; in choosing preventive activities, impact on populations and especially on the distribution of health (ie equity in health) within populations should take precedence. The distinction between population and clinical bases for health policy decisions is made clear by the following example. Individual risk factors for tuberculosis in Russia in order of degree of risk are: low household wealth; incarceration in prison or detention; drug misuse; financial insecurity; unemployed; overcrowded living; living with a person with tuberculosis; and heavy drinking. Population risk factors are different. The two major risks in the population are unemployment and consumption of raw milk.43 Policy decisions should be targeted primarily at risks that are common in the population, not atthe extent of increased risk in individuals.

The lagging performance of the US on virtually every health indicator may be testimony to the high-profile but inadvisable concentration on interventions based on managing risks in individual patients. In the same way, reductions in inequities in health are likely to be intractable in countries where the focus of attention is on the receipt of “indicated care” in largely affluent populations who have access to care. The success of prevention is ultimately measured in population health measures and, increasingly, on reducing avoidable differences in health across population subgroups, rather than on meeting professional criteria for “quality of care”.

In its focus primarily on professionally defined disease entities, the practice of medicine (and particularly the practice of “prevention”) is moving increasingly further from its roots in the care of patients—true “patient-centred care”.29 In view of the large extent of coexistence of diseases (multimorbidity) in individuals and in subpopulations, the increasing rates of adverse events that have no representation in disease statistics, the variability in impact on functioning even within diseases and the disability and dysfunction in the absence of conventional disease labels, there is an urgent need for measures of health that cut across diseases and disease categories (http://www.acg.jhsph.edu). Generic measures based on impact can also be used to good advantage; examples are death rates, disability rates, years of potential life lost, low birthweight and measures such as health-adjusted life expectancy and disability-adjusted life expectancy.

The major challenge is to set priorities based on likely improvements in overall (not disease-specific) health in populations and population subgroups, by conceptualising prevention as a set of activities. The ambitious US-led Goals for the Nation lacked focus on activities driven by the need to improve health more broadly than its current focus on specific diseases. The more recent activities-directed quality objectives (with consequent payment for performance) are activities without health or equity in health goals. The need to ensure better health for populations(especially in developing countries) and better distribution of health (in all countries) demands a refocus on health rather than on preventing specific diseases.

As policy decisions about prevention and care often compete with decisions made on the basis of equity, calculation of the costs and benefits of various preventive strategies should be done both ways, including a cost–consequences approach, in order to make explicit the nature of decisions that societies must make.44


El concepto de prevencion


Otro excelente articulo de Juan Gervas y Barbara Starfield….. el texto completo fue provisto por Ana Carolina Diaz Oliveira. 

Over time, the definition of prevention has expanded so that its meaning in the context of health services is now unclear. As risk factors are increasingly considered to be the equivalent of “diseases” for purposes of intervention, the concept of prevention has lost all practical meaning. This paper reviews the inconsistencies in its utility, and suggests principles that it should follow in the future: a population orientation with explicit consideration of attributable risk, the setting of priorities based on reduction in illness and avoidance of adverse effects, and the imperative to reduce inequities in health.

The scope of prevention has changed over time. A 1967 textbook stated: “Prevention, in a narrow sense, means averting the development of a pathological state. In a broader sense, it includes all measures—definitive therapy among them—that limit the progression of disease at any stage of its course”.1 A distinction was made between interventions that avert the occurrence of disease (primary prevention) and interventions that halt or slow the progression of a disease or its sequelae at any point after its inception (secondary prevention).

By 1978, the distinctions between types of prevention had expanded to include primary prevention to promote health prior to the development of disease or injuries; secondary prevention to detect disease in early (asymptomatic) stages; and tertiary prevention to reverse, arrest or delay progression of disease.2

Neither the 1967 nor the 1978 definitions used the terminology of “risk factor”, but in 1998, the World Health Organization, in addressing “disease” prevention, stated that it “covers measures not only to prevent the occurrence of disease, such as risk factor reduction, but also to arrest its progress and reduce its consequences once established”. The Australian National Public Health Partnership designated prevention as “action to reduce or eliminate or reduce the onset, causes, complications, or recurrence of disease”.3 Several levels were defined: primordial prevention (“preventing the emergence of predisposing social and environmental conditions that can lead to causation of disease;primary prevention; secondary prevention; and tertiary prevention to improve function, minimise impact, and delay complications”).

The Dictionary of Public Health defined prevention similarly, but conceded that the distinction between levels “is more artificial than real”.4

A recent addition to the lexicon of prevention is “quaternary prevention”. The world organisation of family physicians (WONCA) defined quaternary prevention as “an action taken to identify a patient at risk of over-medicalization, to protect him (sic) from new medical invasion, and to suggest to him (sic) interventions which are ethically acceptable”.5 Gofrit et al. defined quaternary prevention as “debriefing, quality assurance, and improvement processes”, which “complete the cycle of prevention by collecting information about the processes, multi-disciplinary analysis of the data, deriving conclusions, and distributing them to all the involved bodies”.6

Quaternary prevention has also been defined by cardiovascular disease experts as “rehabilitation or restoration of function”, applicable to “those with severe cardiovascular dysfuntion”.7 These three definitions are not easily compatible.

Identification of “risk factors” as part of prevention has been designated a new era in public health and clinical medicine8 and as a new professional activity of epidemiologists.9 10 Risk factors, such as elevated blood pressure, are now even considered as “diseases”.11

The shift from public health to clinical disease is evident in the historical development of the concept of prevention. Geoffrey Rose provided the basis for a population orientation to reducing risk factors associated with coronary heart disease, arguing that only a small proportion of cardiovascular events occur in individuals with high risk scores. He maintained that population-based prevention must be low cost, minimally invasive and avoid discomfort and pain. His arguments have been used in ways never intended: to justify treatment of individuals in clinical settings.12 This reflects the emergence of the concept of “preventive medicine”, particularly in the US. Clinical medicine, while increasingly adopting prevention as a field of activity, lacks a definition of prevention: the Guide to Clinical Preventive Services (US Task Force on Prevention) does not offer one despite increasing confusion about the boundaries between the different levels of prevention. The World Health Organization did not include the term “prevention” as a function of health systems, which are defined as “all the activities whose primary purpose is to promote, restore, and maintain health”.13

Is the concept of “prevention”, with its increasing focus on particular diseases and risk factors (rather than on ill health in general), still useful? When so many people lack adequate access to medical care for their manifest health needs, is it justifiable that routine disease check-up visits are approaching half of all medical visits, as in the United States?1416 Is intervention with four drugs, lifestyle advice and cardiacrehabilitation really prevention, as suggested by the title of a published study “Secondary prevention for patients after a myocardial infarction: summary of NICE guidelines”?17 Is intervention to reduce the blood level of a known “risk factor” (eg homocysteine) really prevention when it does not reduce the occurrence of the disease or improve overall health?18 Should controlling risk factors replace the conventional focus on controlling disease, even if it does not necessarily improve health? Should medication (eg cerivastatin) to improve surrogate outcomes in cardiovascular trials19 20 be considered “prevention” when its use is associated with fatal rhabdomyolisis causing it to be withdrawn from theworld market?21 Is it time for a new formulation?

As a result of marked changes in the organsation of health services and increases in knowledge about the genesis and management of disease, there is good reason to question the differentiation of prevention from other aspects of health care.

Clinical settings are increasingly moving towards population-based medicine. As clinical practices become larger, with defined populations, the realities of individual-based medical care now have to confront the principles of population-based care. Increased risk of an event based upon the presence of a “predisposing factor” with high relative risk may no longer be the main criterion for intervention. The “event” may be too uncommon in the population and hence not practical as a priority. Alternatively, the intervention to reduce excess risk, while useful based on statistical associations in clinical trials, may not be useful in other population groups not included in the trial.22 A prime example is the utility of statins for “prevention” of recurrent myocardial infarct in men and the absence of evidence for their utility in either primary or secondary prevention in women.23 The presence of sex differences in screening for abdominal aortic aneurysm provides another example; screening might be useful in at least some men but is not useful in women.24 Clinical trials might not identify population group differences as most, by virtue of their design, are unable to examine the range of individual and community characteristics that could influence responsiveness to interventions.

A preventive activity might be justified in one setting but not in another just because of differences in prevalence, even though the relative risk based on the exposure is the same. What works in one clinical setting may not work in another, even when the relative risk of a characteristic is the same. Population-based studies of the predictive value of exposures consistently find lower likelihood of disease in the presence of a risk factor than do clinically based studies.25 26 As clinical settings are becoming more and more population based, policies regarding the utility of preventive measures are likely to require change.

Perhaps the biggest threat to the concept of prevention, however, is the progressive lowering of thresholds for “predisease”, particularly hypertension, serum cholesterol and blood sugar. With current thresholds, 97% of all US adults aged 50 and over have one or more of these three risk factors, but only 8% of cardiovascular disease will occur in individuals with any combination of them. The United States Preventive Services Task Force (USPSTF) has yet to update its recommendations for people with the changed definition of these conditions.12Encouraged by interests vested in selling more medications for “prevention” and more medical devices for testing, the pressure for increasing “prevention” in clinical care directed at individuals is inexorable—even though it is not well supported by evidence in populations of patients.27

The focus of prevention has always been on “diseases”. As the concept of “disease” is changing over time (with lowering thresholds for designation of “disease”)28 and risk factors are considered equivalent to disease, the boundaries between prevention and cure are becoming increasingly indistinct. Physicians, as a profession, have always had the power to define “diseases” and stages of diseases.29 30 For example, the current definition of heart failure31 includes four stages. Obesity constitutes stage A, even in the absence of symptoms or structural changes in the heart. Stage B also constitutes being “at risk of heart failure”. Only stages C and D constitute evident heart failure.States A and B are preheart failure – a “diagnosis” justifying medication. When drugs are promoted for prevention and the number of patients at risk is very large, the expanded exposure to the drug may lead to important harm.32 The increasing attention to iatrogenic causes of ill health and the resulting addition of “quaternary prevention” also point to the need to explicitly include iatrogenesis as an influence on ill health.

Recommendations for clinical preventive services still focus largely on the results of analyses of relative risk in individuals not necessarily representative of the population or subpopulations.33 Furthermore, recommendations for risk factor screening are made one by one, despite evidence that risk factors are not independent of each other. On average, adult patients in the US in the mid-1990s were estimated to have approximately 12 risk factors requiring approximately 24 preventive services—even before the explosion of the concept of risks.34 A more recent analysis, recognising some of the limitations of estimates of benefit, set several priorities for clinical prevention in the total population based on “preventable burden” and cost-effectiveness; none involved medications other than immunisations.35

The major challenges in setting policy for interventions to reduce illness seem to be:

  1. avoiding the fallacy that risks are independent 
  2. the importance of setting priorities based upon frequency of the desired outcome in populations 
  3. the importance of setting priorities to reduce inequities in health in populations as well as or in preference to improving effectiveness in individuals 
  4. considering when it is more efficient (and perhaps more effective and equitable) to prioritise interventions to populations, includingdefined populations in the clinical sector 
  5. placing priority on improving health generically (as, for example, by reduction in overall and age-specific death rates, by improvementsin life expectancy and by reductions in disability and in perceived poor health) rather than disease by disease33 36 37 
  6. taking into account the patient’s perspective in clinical prevention38 
  7. avoiding incentives for physician activities that are measurable but of low priority for population health gain.39 

A framework (table 1) for conceptualising reductions in the occurrence and severity and progression of disease would both abandon the confusing and outmoded approach to prevention and substitute a framework that distinguishes societal from individual interventions on the one hand and, on the other, distinguishes risks that result from suboptimal physical, social, health service and individual environments.

View this table:
[in this window]
[in a new window]

 

Table 1 Levels and types of interventions to improve health*

 
The increasing world focus on achieving equity in health40 is likely to bring greater pressure on advocates of “prevention” to more clearly delineate the scope of the concept and the nature of ameliorative efforts. If inequities in health are to be reduced or eliminated, the full range of possible interventions needs to be specified and choices made about priorities. The “web” of influences on health and on inequity in health is very broad, ranging from societal influences to policy influences, to community influences, to social relationships and to individual characteristics (innate as well as developmental, biological and behavioural).41 The possibilities for prevention are vast, involving very differenttypes of approaches and constituencies because prevention involves virtually every sector of societal, social and individual endeavour.

It would be presumptuous to suggest that the term “prevention”, which is so widely entrenched in medical thinking and supported by committed constituencies, could be discarded even if its vagueness is largely dysfunctional. It may be possible, however, to seek agreement on two critical aspects: a focus on population health and a focus on reducing disparities (inequities) in health.

“Population based” is no longer synonymous with “public health”. Public health constitutes societal approaches to improving health, but “population based” means that evidence is derived from population statistics rather than from individual patients in unrepresentative clinical practice. Priorities for action are made on the basis of population-based evidence, which includes consideration of attributable risk as well as relative risk. The hazards of clinical prevention have been catalogued42 and include such considerations as absence of evidence relevant to setting priorities and imprecision of rules allowing prediction of benefit; competition of clinical preventive activities with care of manifest problems; and compromised health resulting from preventive interventions. In view of the systematic dismantling of the public health infrastructure in at least some countries with concomitant increases in the scope and influence of clinical services, an adoption of populationprinciples for clinical services would appear to be in order.

A fresh approach to prevention requires a refocusing of attention from evidence relevant to individuals to evidence relevant to populations—even those in clinical settings. Preventive activities have widely differing effectiveness; in choosing preventive activities, impact on populations and especially on the distribution of health (ie equity in health) within populations should take precedence. The distinction between population and clinical bases for health policy decisions is made clear by the following example. Individual risk factors for tuberculosis in Russia in order of degree of risk are: low household wealth; incarceration in prison or detention; drug misuse; financial insecurity; unemployed; overcrowded living; living with a person with tuberculosis; and heavy drinking. Population risk factors are different. The two major risks in the population are unemployment and consumption of raw milk.43 Policy decisions should be targeted primarily at risks that are common in the population, not atthe extent of increased risk in individuals.

The lagging performance of the US on virtually every health indicator may be testimony to the high-profile but inadvisable concentration on interventions based on managing risks in individual patients. In the same way, reductions in inequities in health are likely to be intractable in countries where the focus of attention is on the receipt of “indicated care” in largely affluent populations who have access to care. The success of prevention is ultimately measured in population health measures and, increasingly, on reducing avoidable differences in health across population subgroups, rather than on meeting professional criteria for “quality of care”.

In its focus primarily on professionally defined disease entities, the practice of medicine (and particularly the practice of “prevention”) is moving increasingly further from its roots in the care of patients—true “patient-centred care”.29 In view of the large extent of coexistence of diseases (multimorbidity) in individuals and in subpopulations, the increasing rates of adverse events that have no representation in disease statistics, the variability in impact on functioning even within diseases and the disability and dysfunction in the absence of conventional disease labels, there is an urgent need for measures of health that cut across diseases and disease categories (http://www.acg.jhsph.edu). Generic measures based on impact can also be used to good advantage; examples are death rates, disability rates, years of potential life lost, low birthweight and measures such as health-adjusted life expectancy and disability-adjusted life expectancy.

The major challenge is to set priorities based on likely improvements in overall (not disease-specific) health in populations and population subgroups, by conceptualising prevention as a set of activities. The ambitious US-led Goals for the Nation lacked focus on activities driven by the need to improve health more broadly than its current focus on specific diseases. The more recent activities-directed quality objectives (with consequent payment for performance) are activities without health or equity in health goals. The need to ensure better health for populations(especially in developing countries) and better distribution of health (in all countries) demands a refocus on health rather than on preventing specific diseases.

As policy decisions about prevention and care often compete with decisions made on the basis of equity, calculation of the costs and benefits of various preventive strategies should be done both ways, including a cost–consequences approach, in order to make explicit the nature of decisions that societies must make.44


USPSTF: Guia para cribado de cancer de colon


right arrow U.S. Preventive Services Task Force* 

4 November 2008 | Volume 149 Issue 9

Description: Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation statement on screening for colorectal cancer.

Methods: In order to update its recommendation, the USPSTF commissioned 2 studies: 1) a targeted systematic evidence review on 4 selected questions relating to test characteristics andbenefits and harms of screening technologies; and 2) a decision analytic modeling analysis using population modeling techniques to compare the expected health outcomes and resource requirements of available screening modalities when used in a programmatic way over time.

Recommendations: The USPSTF recommends screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy in adults, beginning at age 50 years and continuing until age 75 years. The risks and benefits of these screening methods vary. (A recommendation.)

The USPSTF recommends against routine screening for colorectal cancer in adults 76 to 85 years of age. There may be considerations that support colorectal cancer screening in an individual patient. (C recommendation.)

The USPSTF recommends against screening for colorectal cancer in adults older than age 85 years. (D recommendation.)

The USPSTF concludes that the evidence is insufficient to assess the benefits and harms of computed tomographic colonographyand fecal DNA testing as screening modalities for colorectal cancer. (I statement.)

USPSTF: Guia para cribado de cancer de colon


right arrow U.S. Preventive Services Task Force* 

4 November 2008 | Volume 149 Issue 9

Description: Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation statement on screening for colorectal cancer.

Methods: In order to update its recommendation, the USPSTF commissioned 2 studies: 1) a targeted systematic evidence review on 4 selected questions relating to test characteristics andbenefits and harms of screening technologies; and 2) a decision analytic modeling analysis using population modeling techniques to compare the expected health outcomes and resource requirements of available screening modalities when used in a programmatic way over time.

Recommendations: The USPSTF recommends screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy in adults, beginning at age 50 years and continuing until age 75 years. The risks and benefits of these screening methods vary. (A recommendation.)

The USPSTF recommends against routine screening for colorectal cancer in adults 76 to 85 years of age. There may be considerations that support colorectal cancer screening in an individual patient. (C recommendation.)

The USPSTF recommends against screening for colorectal cancer in adults older than age 85 years. (D recommendation.)

The USPSTF concludes that the evidence is insufficient to assess the benefits and harms of computed tomographic colonographyand fecal DNA testing as screening modalities for colorectal cancer. (I statement.)

Prevencion de Cancer de Cuello de utero y vacuna VPH


Gérvas J. La incierta prevención del cáncer de cuello de útero con la vacuna contra el virus del papiloma humano. Rev Port Clín Geral. 2007;23: 547-55

Gérvas, J. Prevention of cervical cancer by the HPV vaccine is not definitive. Rev. Port Clin Geral. 2007; 23: 547-55.

Juan Gérvas
jgervasc@meditex.es
Médico de Canencia de la Sierra, Garganta de los Montes y El Cuadrón (Madrid) España
Equipo CESCA, Madrid, España

Abstract with Eleven Questions & Answers into Spanish and English.
English translation by Juan Gérvas (“nogracias” Spain, http://www.nogracias.eu) and Joana Ramos, (www.healthyskepticism.og )

Resumen
En 2007 se ha comercializado de la vacuna contra el virus del papiloma humano, con la que se propone vacunar a niñas de 11 y 12 años para la prevención primaria del cáncer de cuello de útero, dada la fuerte asociación entre el cáncer y algunos tipos oncogénicos del virus. La vacuna ha sido rápidamente incluida en los calendarios vacunales de la mayoría de los países desarrollados. En este texto se revisa el fundamento científico de dicha decisión. Son puntos clave: la ausencia de cambios en la epidemiología de la infección, la estabilidad o disminución del la incidencia y mortalidad del cáncer de cuello de útero, la falta de correlación entre respuesta inmunitaria serológica y la inmunidad natural, el impacto de la vacuna en la ecología del virus, las evaluaciones coste-efectividad que dependen de la duración desconocida de la inmunización, la dependencia excesiva de la investigación financiada por la industria farmacéutica, y la necesidad de mantener la citología de cribado. Se precisaría más tiempo e información antes de introducir la vacunación en el calendario vacunal.
Palabras clave: Vacunas, Virus del papiloma humano, Evaluación.

Abstract
Sales of the vaccine against human papilloma virus began in 2007, promoted for administration in girls 11 -12 years old, as preventative measure against cervical cancer, due to the strong link between this cancer with the presence of certain oncogenic strains of the papilloma virus. The vaccine was quickly included in the official immunization programs in many developed countries. In this paper I review the scientific basis for that decision. Critical questions for review are: the absence of changes in the epidemiology of the infection; stability or reduction in the incidence and mortality from cervical cancer; lack of correlation between levels of serologic immune response and natural immunity; the effect of the vaccine on virus ecology; evaluation of the cost-effectiveness of immunization in the face of lack of definitive information about the length of its effectiveness; pharmaceutical industry sponsorship of most of the HPV vaccine research; and the need to maintain screening with Papanicolau exams. More time and information are needed before including this vaccine in the official immunization program.
Key words: Vaccines, Human papilloma virus, Evaluation.

Once preguntas básicas (sin respuesta concluyente)
Eleven basic questions (with no definitive answer)

Con un ímpetu frenético, sin parangón en el campo vacunal, la vacuna contra el virus del papiloma humano se ha incluido en los calendarios vacunales de casi todos los países europeos, Alemania, Austria, Bélgica, Dinamarca, España, Grecia, Holanda, Italia, Luxemburgo, Reino Unido, Suecia y Suiza (1) y en otros desarrollados como Australia, Canadá y EEUU.
With a speed never before seen in the field of immunization, the HPV vacccine has been added to the vaccination schedules of almost all the European countries, including Germany, Austria, Belgium, Denmark, Spain, Greece, the Netherlands, Italy, Luxemburg, the UK, and Switzerland (1) and in other developed nations like Australia, Canada, and the USA.

¿Indica la unanimidad lógica y certeza científica? No. La prevención es campo aparte, como se deduce de otros casos; por ejemplo, respecto al cribado de la displasia del desarrollo de caderas en el recién nacido (2-4).
Does this mean that there is complete agreement and solid scientific basis for this action? No.
The field of preventive medicine is a whole different matter as we can learn from other cases; for example, with respect to screening of newborns for hip displasia (2-4).

En el caso de la vacuna contra el virus del papiloma humano existen dudas razonables acerca de la racionalidad de la decisión de su inclusión en el calendario vacunal. Al menos hay once preguntas básicas sin respuesta concluyente, que hacen dudar de la oportunidad de la aprobación del nuevo calendario:
Reasonable doubts exist about the rationale for the decision to include the HPV vaccine in the immunization schedules. At the very least, there are eleven basic unresolved questions, which raise doubts about the appropriateness of its inclusion in the new [vaccination] schedule.

¿Hay cambios recientes en lo que respecta a la infección por virus del papiloma humano? No. De hecho, desconocemos su historia natural. Es la enfermedad de transmisión sexual más frecuente y la más benigna (el 90% de las infecciones curan espontáneamente) (5). Seguimos sin saber porqué algunas infecciones son persistentes y cancerígenas (al cabo de 20-30 años provocan cáncer de cuello de útero).
Have there been any recent changes in our understanding of the papilloma virus infection? No.
In fact we do not know its natural history. It is the most common sexually transmitted disease, but most cases are benign (90% clear spontaneously) (5). We still don’t know why some infections become chronic and cause cancer (it takes about 20-30 years for [the infection] to transform into cervical cancer).

2. ¿Hay cambios en los países desarrollados de la epidemiología del cáncer de cuello de útero que lo justifiquen? Por ejemplo, en España la incidencia se mantiene estable y baja, así como la mortalidad (respectivamente, de 7,11 y de 2,4 casos por 100.000 mujeres y año) (6). En EEUU disminuye, y cada año hay unos 11.100 nuevos casos y unas 3.700 muertes por cáncer de cuello de útero (5).

Are there known changes in the epidemiology of cervical cancer in developed countries that would justify vacciantion? No.
In most developed countries mortality is stable or decreasing.
No. In Spain, for example, the incidence has remained stable to low, as has the monthly rate (some 7. 11 cases and 2.4 deaths yearly per 100,000 women, respectively) (6). In the USA, there has been a decrease, and there are about 11,100 new cases and about 3700 deaths from cervical cancer annually (5).

3. ¿La inmunidad natural, ¿conlleva la presencia de anticuerpos en sangre? No. La cifra de anticuerpos en sangre es muy baja o inexistente (en la mitad de los casos) en las mujeres inmunes naturalmente. La infección no conlleva viremia (la replicación vírica se produce en la superficie epitelial, muy lejos de la células presentadoras de antígeno y de los macrófagos) (7). Desconocemos en detalle la respuesta inmunológica normal, pero es muy efectiva. Además, no se ve afectada por la re-exposición debida a la actividad sexual continuada.

Is natural immunity correlated with levels of antibodies in the blood? No.
In most cases, the quantity of blood antibodies is very low to nonexistent (in half of all cases) among women with natural immunity. Infection does not correlate with viremia (viral replication occurs on the epithelial surface, very far from the antigen-presenting cells and from the macrophages) (7). Viral replication is a cellular phenomenon. We do not understand very well the normal immune response, but it is very effective. Furthermore, it does not seem to be affected by re-exposure resulting from ongoing sexual activity.

4. La vacuna, y re-vacuna, provoca la presencia en sangre de anticuerpos, en dosis de hasta veinte veces las máximas normales, pero ¿existe relación demostrada entre el nivel de anticuerpos y la eficacia de la vacuna? No. No hay correlación inmunológica demostrada. Ignoramos el mecanismo de acción de la vacuna. Se supone que los anticuerpos en sangre ayudan a eliminar los virus en la superficie epitelial, pero no sabemos cómo (5, 8). La inmunidad natural es celular, no serológica.

Vaccination, and re-vaccination, boost the presence of antibodies in the blood, up to twenty times the normal maximum counts, but is there any relationship shown between the antibody levels and the effectiveness of the vaccine? No.
There is no immunological correlation shown at all. The vaccine’s mode of action is unknown. It is theorized that antibodies in blood might help in getting rid of the infection, but we don’t know how (5,8). Natural immunity is cellular, not serological.

5. Si la vacuna elimina los virus, puede tener un doble efecto beneficioso y perjudicial? Por ejemplo, la vacuna disminuye las infecciones persistentes y las lesiones pre-malignas causadas por los virus contra los que se vacuna (beneficioso). Pero si eliminase otros virus del papiloma humano no sabríamos cómo valorarlo. Por ejemplo, la co-infección con los tipos 6 y 11 (bajo riesgo oncológico) disminuye naturalmente la posibilidad de ser infectado por el tipo 16 (alto riesgo oncológico) (9). En general se acepta que la vacuna evita la presencia o actividad de los virus contra los que vacuna. Por ello cambia la “ecología” del cuello uterino y alrededores, y hay datos (10) que sugieren un efecto de “nicho vacío”, que permite la proliferación de otros virus de alto riesgo oncológico, o la transformación de los de bajo riesgo.

If the vaccine eliminates the viruses, is it possible that it might have two effects, both beneficial and harmful? Yes.
For example, the vaccine might reduce chronic infections and pre-malignant lesions caused by the viruses which the vaccine acts against (helpful). But if this eliminated other human papilloma viruses, we wouldn’t know how to assess such a change. For example, co-infection with types 6 and 11 (low cancer risk) naturally decreases the probability of infection by type 16 (high cancer risk) (9). It is generally accepted that the vaccination blocks the appearance or activation of the viruses that it targets. Because of these changes occur in the “ecology” of the uterine cervix and surrounding areas, and there are data (10) to support the existence of an “empty niche” effect, that permits the proliferation of other high cancer risk viruses, or that permits the transformation of low-risk viruses into high-risk ones.

6. ¿Se ha demostrado su efectividad? No; no se tienen datos sobre su resultado en la práctica clínica diaria, ni siquiera ensayos clínicos con resultados en salud en las niñas en que se propone la vacunación. Se tienen datos de eficacia de casi el 100% (resultados de ensayos clínicos para los que cumplen todas las condiciones ideales, muy diferentes de la clínica diaria), para lesiones asociadas a los virus contra los que se vacuna, en mujeres de 16 a 26 años, generalmente blancas, sanas, de países desarrollados y educadas (10-14). Cuando se tiene en cuenta “la intención de tratar” (se incluyen todos los pacientes participantes en los ensayos, aunque no hayan cumplido las condiciones ideales) la eficacia baja al 50% (10-14), y si se incluyen las lesiones no asociadas a los virus contra los que se vacuna, la eficacia baja hasta el 17% (11).

Has the vaccine been shown to be effective? No.
There are no clinical data about its effectiveness, nor have there been clinical trials showing health outcomes for girls in the age group being targeted for vaccination. There is data showing almost 100% effectiveness (results from clinical trials conducted under the most ideal conditions, quite different from real-life clinical practice) for lesions associated with the viruses that the vaccine targets, in women ages 16 to 26, who were mostly white, healthy, well educated and living in developed countries (10-14). When “intention to treat” is taken into account (if all patients who participated in the trials are included, even if not meeting ideal inclusion criteria), the vaccine’s effectiveness decreases to 50% (10-14). And if all those patients whose cervical lesions are not associated with the viruses targeted by the vaccine are included then the rate of effectiveness of the vaccine falls to 17% (11).

7. ¿Se sabe cuánto dura la inmunidad? No, no se sabe. Lo máximo demostrado son cinco años. Si la inmunidad decae, se podría precisar de una re-vacunación cada cierto tiempo. Además del gasto y complicaciones que ello implica, no sabemos si al ceder la inmunidad artificial se debilitaría la inmunidad natural y habría infecciones oncogénicas más graves y agresivas (algo parecido sucede con la vacunación contra la varicela) (7,12).

Do we know how long immunity [from the vaccine] will last? No.
So far, it has been shown to work for five years. If immunity would decrease, then re-vaccination would be necessary after a certain length of time. Besides the expense and logistical complications this would entail, we do not know if inducing artificial immunity would inhibit natural immunity, resulting in serious and more aggressive oncogenic infections. (something similar to what has happened with small pox vaccination) (7,12).

8. ¿Se ha determinado el coste-efectividad de la vacuna? Sí. Pero se asumen condiciones no demostradas. Especialmente respecto a la efectividad y respecto a la duración de la vacuna. De hecho, en condiciones muy probables, si la inmunidad provocada por la vacuna dura menos de treinta años, y si la efectividad es del 70%, en Canadá, el coste-efectividad es nulo. Es decir, habría que vacunar a infinitas niñas para evitar un caso de cáncer de cuello de útero (15).

Has the vaccine’s cost-effectivenes been determined? Yes.
But some unproven assumptions have been made about its effectiveness and duration of immunity it offers. In fact, under ordinary conditions, if the period of immunity from the vaccine lasts less than 30 years, and if its rate of effectiveness is 70%, in the case of Canada, then it is not cost-effective at all. In other words, it would be necessary to vaccinate all girls in order to prevent one case of cervical cancer (15).

9. ¿Sirve en mujeres que ya han iniciado la actividad sexual? No. Las mujeres se contagian al comienzo de la actividad sexual. La eficacia (ensayos clínicos, condiciones ideales) es muy baja en mujeres que ya han iniciado la actividad sexual, de alrededor del 17% (10,16). Es una vacuna profiláctica (que evita el contagio), no terapéutica (que elimine el virus de las células epiteliales) (5, 10).

Is the vaccine effective for women who are already sexually active? No.
Women get the infection when they become sexually active. Clinical trials done under ideal conditions show that the vaccine has very low efficacy in sexually active women, about 17% (10,16). The vaccine is prophylactic (blocks transmission), not therapeutic (which would eliminate virus in the epithelial cells) (5, 10).

10. ¿Hay ensayos clínicos y estudios independientes, no financiados o promovidos por la industria farmacéutica? No, o son irrelevantes. El grueso de la investigación sobre la vacuna contra el virus del papiloma humano ha dependido, depende y dependerá de la industria que fabrica dichas vacunas (10). Se ignora porqué los gobiernos de los países desarrollados han renunciado a tener un papel activo en el conjunto de la salud sexual, y se reservan sólo el papel pasivo de “pagador” de la vacuna.

Are there clinical trials and independent research that have not been financed or sponsored by the pharmaceutical industry? No, or if so, they are irrelevant.
The bulk of the research on the HPV vaccine has been, is, and will continue to be dependent on the manufacturers of the vaccine. It is unclear why the governments of wealthy countries have declined to take an active role in this area of sexual health services, and instead have assumed merely a passive role as “payor” for the vaccine (10).

11. ¿Se precisa mantener el programa actual de detección precoz del cáncer de cuello de útero? Sí. Los actuales programas de cribaje con la citología (Papanicolau) tienen graves problemas de cobertura y fundamento científico, pero la vacuna no los evita, pues combate sólo dos de los quince virus oncogénicos. No sabemos en qué forma se modificará la sensibilidad y especificidad del cribaje (5,7).
Is it still necessary to continue the current early dectection programs for cervical cancer? Yes.
Current screening programs to detect cervical cancer by cytology (Pap smears) have serious problems in terms of patient access as well as scientific basis, the vaccine doesn’t replace them, as the vaccine only acts against 2 of the 15 oncogenic viruses. We do not know how the specificity and sensibility of screening tests should be modified (5,7).

Bibliografía
Bibliography

Vacuna.org. Calendario de vacunación. Europa. http://www.vacunas.org/index.php?option=com_content&task=view&id=2472&Itemid=336. Consultado el 13 de octubre de 2007.
Gervas J, Pérez Fernández M, González de Dios J. Problemas prácticos y éticos de la prevención secundaria. A propósito de dos ejemplos en pediatría. Rev Esp Salud Pública. 2007;81:345-52.
Starfield B, Hyde J, Gérvas J, Heath I. The concept of prevention: a good idea gone astray? J Epidemiol Community Health. 2008 [in press].
Gérvas J, Starfield B, Heath I. Caution in clinical prevention. Lancet. 2008 [in press].
Markowitz LE, Dunne EF, Saraiya M, Lawson HW, Chessm H, Unger E for the ACIP. Quatrivalent human papilloma virus vaccine. MMWR. 2007;56(RR02): 1-24.
Galceran J, Marcos R, Izquierdo A, Borrás J. Carcinoma invasor y lesiones premalignas del cuello uterino en los registros poblacionales: utilidad y limitaciones. En: Sanjosé S, García A (coordinadoras). Madrid: Sociedad Española de Epidemiología (4ª Monografía); 2006. p. 15-29.
Navarro JA, Bernal PJ, Pérez JJ. Interrogantes en la introducción de la vacuna frente al virus del papiloma humano en los calendarios sistemáticos. Med Clín (Barc). 2007;129:55-60.
EMEA. EPARS for authorised medicinal products. Gardasil. http://www.emea.europa.eu/humandocs/Humans/EPAR/gardasil/gardasil.htm. Consultado el 13 de octubre de 2007.
Hughes JP, Garnett GP, Koutsky L. The theoretical population-level impact of a prophylactic human papilloma virus vaccine. Epidemiol. 2002;13: 361-9.
Sawaya GF, Smith K. HPV vaccination. More answers, more questions. N Engl J Med. 2007;356:1991-3.
Kahn JA, Burk RD. Papillomavirus vaccines in perspective. Lancet. 2007;369:2135-7.
Lippman A, Melnychuk R, Shimmin C, Boscope M. Human papillovirus, vaccines and women’s health: questions and cautions. CMAJ. 2007;177:484-7.
Joura EA, Leodoter S, Hernández-Ávila M, Wheeler CM, Pérez G, Loutsky LA et al. Efficacy or quadrivalent prophylactic human papillomavirus (types 6, 11,16, and 18) L1 virus-like-particle vaccine against high-grade vulvar, and vaginal lesions: a combined analysis of three randomised clinical trials. Lancet. 2007;369:1693-702.
Rambout L, Hopkins L, Hutton B, Fergusson D. Prophylactic vaccination against human papillomavirus infection and disease in women: a systematic review of randomized controlled trials. CMAJ. 2007;177:469-79.
Brisson M, Velde N, Wals P, Boily MC. Estimating the number needed to vaccinate to prevent diseases and death related to human papillomavirus infection. CMAJ. 2007;175:464-8.
Future II Study Group. Quatrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions. N Engl J Med. 2007:356:1915-27.

Fuente: Gervas, J. (2008, June 8). June08. Retrieved Sep. 21, 2008, from http://www.healthyskepticism.org/news/2008/June08.htm.

Prevencion de Cancer de Cuello de utero y vacuna VPH


Gérvas J. La incierta prevención del cáncer de cuello de útero con la vacuna contra el virus del papiloma humano. Rev Port Clín Geral. 2007;23: 547-55

Gérvas, J. Prevention of cervical cancer by the HPV vaccine is not definitive. Rev. Port Clin Geral. 2007; 23: 547-55.

Juan Gérvas
jgervasc@meditex.es
Médico de Canencia de la Sierra, Garganta de los Montes y El Cuadrón (Madrid) España
Equipo CESCA, Madrid, España

Abstract with Eleven Questions & Answers into Spanish and English.
English translation by Juan Gérvas (“nogracias” Spain, http://www.nogracias.eu) and Joana Ramos, (www.healthyskepticism.og )

Resumen
En 2007 se ha comercializado de la vacuna contra el virus del papiloma humano, con la que se propone vacunar a niñas de 11 y 12 años para la prevención primaria del cáncer de cuello de útero, dada la fuerte asociación entre el cáncer y algunos tipos oncogénicos del virus. La vacuna ha sido rápidamente incluida en los calendarios vacunales de la mayoría de los países desarrollados. En este texto se revisa el fundamento científico de dicha decisión. Son puntos clave: la ausencia de cambios en la epidemiología de la infección, la estabilidad o disminución del la incidencia y mortalidad del cáncer de cuello de útero, la falta de correlación entre respuesta inmunitaria serológica y la inmunidad natural, el impacto de la vacuna en la ecología del virus, las evaluaciones coste-efectividad que dependen de la duración desconocida de la inmunización, la dependencia excesiva de la investigación financiada por la industria farmacéutica, y la necesidad de mantener la citología de cribado. Se precisaría más tiempo e información antes de introducir la vacunación en el calendario vacunal.
Palabras clave: Vacunas, Virus del papiloma humano, Evaluación.

Abstract
Sales of the vaccine against human papilloma virus began in 2007, promoted for administration in girls 11 -12 years old, as preventative measure against cervical cancer, due to the strong link between this cancer with the presence of certain oncogenic strains of the papilloma virus. The vaccine was quickly included in the official immunization programs in many developed countries. In this paper I review the scientific basis for that decision. Critical questions for review are: the absence of changes in the epidemiology of the infection; stability or reduction in the incidence and mortality from cervical cancer; lack of correlation between levels of serologic immune response and natural immunity; the effect of the vaccine on virus ecology; evaluation of the cost-effectiveness of immunization in the face of lack of definitive information about the length of its effectiveness; pharmaceutical industry sponsorship of most of the HPV vaccine research; and the need to maintain screening with Papanicolau exams. More time and information are needed before including this vaccine in the official immunization program.
Key words: Vaccines, Human papilloma virus, Evaluation.

Once preguntas básicas (sin respuesta concluyente)
Eleven basic questions (with no definitive answer)

Con un ímpetu frenético, sin parangón en el campo vacunal, la vacuna contra el virus del papiloma humano se ha incluido en los calendarios vacunales de casi todos los países europeos, Alemania, Austria, Bélgica, Dinamarca, España, Grecia, Holanda, Italia, Luxemburgo, Reino Unido, Suecia y Suiza (1) y en otros desarrollados como Australia, Canadá y EEUU.
With a speed never before seen in the field of immunization, the HPV vacccine has been added to the vaccination schedules of almost all the European countries, including Germany, Austria, Belgium, Denmark, Spain, Greece, the Netherlands, Italy, Luxemburg, the UK, and Switzerland (1) and in other developed nations like Australia, Canada, and the USA.

¿Indica la unanimidad lógica y certeza científica? No. La prevención es campo aparte, como se deduce de otros casos; por ejemplo, respecto al cribado de la displasia del desarrollo de caderas en el recién nacido (2-4).
Does this mean that there is complete agreement and solid scientific basis for this action? No.
The field of preventive medicine is a whole different matter as we can learn from other cases; for example, with respect to screening of newborns for hip displasia (2-4).

En el caso de la vacuna contra el virus del papiloma humano existen dudas razonables acerca de la racionalidad de la decisión de su inclusión en el calendario vacunal. Al menos hay once preguntas básicas sin respuesta concluyente, que hacen dudar de la oportunidad de la aprobación del nuevo calendario:
Reasonable doubts exist about the rationale for the decision to include the HPV vaccine in the immunization schedules. At the very least, there are eleven basic unresolved questions, which raise doubts about the appropriateness of its inclusion in the new [vaccination] schedule.

¿Hay cambios recientes en lo que respecta a la infección por virus del papiloma humano? No. De hecho, desconocemos su historia natural. Es la enfermedad de transmisión sexual más frecuente y la más benigna (el 90% de las infecciones curan espontáneamente) (5). Seguimos sin saber porqué algunas infecciones son persistentes y cancerígenas (al cabo de 20-30 años provocan cáncer de cuello de útero).
Have there been any recent changes in our understanding of the papilloma virus infection? No.
In fact we do not know its natural history. It is the most common sexually transmitted disease, but most cases are benign (90% clear spontaneously) (5). We still don’t know why some infections become chronic and cause cancer (it takes about 20-30 years for [the infection] to transform into cervical cancer).

2. ¿Hay cambios en los países desarrollados de la epidemiología del cáncer de cuello de útero que lo justifiquen? Por ejemplo, en España la incidencia se mantiene estable y baja, así como la mortalidad (respectivamente, de 7,11 y de 2,4 casos por 100.000 mujeres y año) (6). En EEUU disminuye, y cada año hay unos 11.100 nuevos casos y unas 3.700 muertes por cáncer de cuello de útero (5).

Are there known changes in the epidemiology of cervical cancer in developed countries that would justify vacciantion? No.
In most developed countries mortality is stable or decreasing.
No. In Spain, for example, the incidence has remained stable to low, as has the monthly rate (some 7. 11 cases and 2.4 deaths yearly per 100,000 women, respectively) (6). In the USA, there has been a decrease, and there are about 11,100 new cases and about 3700 deaths from cervical cancer annually (5).

3. ¿La inmunidad natural, ¿conlleva la presencia de anticuerpos en sangre? No. La cifra de anticuerpos en sangre es muy baja o inexistente (en la mitad de los casos) en las mujeres inmunes naturalmente. La infección no conlleva viremia (la replicación vírica se produce en la superficie epitelial, muy lejos de la células presentadoras de antígeno y de los macrófagos) (7). Desconocemos en detalle la respuesta inmunológica normal, pero es muy efectiva. Además, no se ve afectada por la re-exposición debida a la actividad sexual continuada.

Is natural immunity correlated with levels of antibodies in the blood? No.
In most cases, the quantity of blood antibodies is very low to nonexistent (in half of all cases) among women with natural immunity. Infection does not correlate with viremia (viral replication occurs on the epithelial surface, very far from the antigen-presenting cells and from the macrophages) (7). Viral replication is a cellular phenomenon. We do not understand very well the normal immune response, but it is very effective. Furthermore, it does not seem to be affected by re-exposure resulting from ongoing sexual activity.

4. La vacuna, y re-vacuna, provoca la presencia en sangre de anticuerpos, en dosis de hasta veinte veces las máximas normales, pero ¿existe relación demostrada entre el nivel de anticuerpos y la eficacia de la vacuna? No. No hay correlación inmunológica demostrada. Ignoramos el mecanismo de acción de la vacuna. Se supone que los anticuerpos en sangre ayudan a eliminar los virus en la superficie epitelial, pero no sabemos cómo (5, 8). La inmunidad natural es celular, no serológica.

Vaccination, and re-vaccination, boost the presence of antibodies in the blood, up to twenty times the normal maximum counts, but is there any relationship shown between the antibody levels and the effectiveness of the vaccine? No.
There is no immunological correlation shown at all. The vaccine’s mode of action is unknown. It is theorized that antibodies in blood might help in getting rid of the infection, but we don’t know how (5,8). Natural immunity is cellular, not serological.

5. Si la vacuna elimina los virus, puede tener un doble efecto beneficioso y perjudicial? Por ejemplo, la vacuna disminuye las infecciones persistentes y las lesiones pre-malignas causadas por los virus contra los que se vacuna (beneficioso). Pero si eliminase otros virus del papiloma humano no sabríamos cómo valorarlo. Por ejemplo, la co-infección con los tipos 6 y 11 (bajo riesgo oncológico) disminuye naturalmente la posibilidad de ser infectado por el tipo 16 (alto riesgo oncológico) (9). En general se acepta que la vacuna evita la presencia o actividad de los virus contra los que vacuna. Por ello cambia la “ecología” del cuello uterino y alrededores, y hay datos (10) que sugieren un efecto de “nicho vacío”, que permite la proliferación de otros virus de alto riesgo oncológico, o la transformación de los de bajo riesgo.

If the vaccine eliminates the viruses, is it possible that it might have two effects, both beneficial and harmful? Yes.
For example, the vaccine might reduce chronic infections and pre-malignant lesions caused by the viruses which the vaccine acts against (helpful). But if this eliminated other human papilloma viruses, we wouldn’t know how to assess such a change. For example, co-infection with types 6 and 11 (low cancer risk) naturally decreases the probability of infection by type 16 (high cancer risk) (9). It is generally accepted that the vaccination blocks the appearance or activation of the viruses that it targets. Because of these changes occur in the “ecology” of the uterine cervix and surrounding areas, and there are data (10) to support the existence of an “empty niche” effect, that permits the proliferation of other high cancer risk viruses, or that permits the transformation of low-risk viruses into high-risk ones.

6. ¿Se ha demostrado su efectividad? No; no se tienen datos sobre su resultado en la práctica clínica diaria, ni siquiera ensayos clínicos con resultados en salud en las niñas en que se propone la vacunación. Se tienen datos de eficacia de casi el 100% (resultados de ensayos clínicos para los que cumplen todas las condiciones ideales, muy diferentes de la clínica diaria), para lesiones asociadas a los virus contra los que se vacuna, en mujeres de 16 a 26 años, generalmente blancas, sanas, de países desarrollados y educadas (10-14). Cuando se tiene en cuenta “la intención de tratar” (se incluyen todos los pacientes participantes en los ensayos, aunque no hayan cumplido las condiciones ideales) la eficacia baja al 50% (10-14), y si se incluyen las lesiones no asociadas a los virus contra los que se vacuna, la eficacia baja hasta el 17% (11).

Has the vaccine been shown to be effective? No.
There are no clinical data about its effectiveness, nor have there been clinical trials showing health outcomes for girls in the age group being targeted for vaccination. There is data showing almost 100% effectiveness (results from clinical trials conducted under the most ideal conditions, quite different from real-life clinical practice) for lesions associated with the viruses that the vaccine targets, in women ages 16 to 26, who were mostly white, healthy, well educated and living in developed countries (10-14). When “intention to treat” is taken into account (if all patients who participated in the trials are included, even if not meeting ideal inclusion criteria), the vaccine’s effectiveness decreases to 50% (10-14). And if all those patients whose cervical lesions are not associated with the viruses targeted by the vaccine are included then the rate of effectiveness of the vaccine falls to 17% (11).

7. ¿Se sabe cuánto dura la inmunidad? No, no se sabe. Lo máximo demostrado son cinco años. Si la inmunidad decae, se podría precisar de una re-vacunación cada cierto tiempo. Además del gasto y complicaciones que ello implica, no sabemos si al ceder la inmunidad artificial se debilitaría la inmunidad natural y habría infecciones oncogénicas más graves y agresivas (algo parecido sucede con la vacunación contra la varicela) (7,12).

Do we know how long immunity [from the vaccine] will last? No.
So far, it has been shown to work for five years. If immunity would decrease, then re-vaccination would be necessary after a certain length of time. Besides the expense and logistical complications this would entail, we do not know if inducing artificial immunity would inhibit natural immunity, resulting in serious and more aggressive oncogenic infections. (something similar to what has happened with small pox vaccination) (7,12).

8. ¿Se ha determinado el coste-efectividad de la vacuna? Sí. Pero se asumen condiciones no demostradas. Especialmente respecto a la efectividad y respecto a la duración de la vacuna. De hecho, en condiciones muy probables, si la inmunidad provocada por la vacuna dura menos de treinta años, y si la efectividad es del 70%, en Canadá, el coste-efectividad es nulo. Es decir, habría que vacunar a infinitas niñas para evitar un caso de cáncer de cuello de útero (15).

Has the vaccine’s cost-effectivenes been determined? Yes.
But some unproven assumptions have been made about its effectiveness and duration of immunity it offers. In fact, under ordinary conditions, if the period of immunity from the vaccine lasts less than 30 years, and if its rate of effectiveness is 70%, in the case of Canada, then it is not cost-effective at all. In other words, it would be necessary to vaccinate all girls in order to prevent one case of cervical cancer (15).

9. ¿Sirve en mujeres que ya han iniciado la actividad sexual? No. Las mujeres se contagian al comienzo de la actividad sexual. La eficacia (ensayos clínicos, condiciones ideales) es muy baja en mujeres que ya han iniciado la actividad sexual, de alrededor del 17% (10,16). Es una vacuna profiláctica (que evita el contagio), no terapéutica (que elimine el virus de las células epiteliales) (5, 10).

Is the vaccine effective for women who are already sexually active? No.
Women get the infection when they become sexually active. Clinical trials done under ideal conditions show that the vaccine has very low efficacy in sexually active women, about 17% (10,16). The vaccine is prophylactic (blocks transmission), not therapeutic (which would eliminate virus in the epithelial cells) (5, 10).

10. ¿Hay ensayos clínicos y estudios independientes, no financiados o promovidos por la industria farmacéutica? No, o son irrelevantes. El grueso de la investigación sobre la vacuna contra el virus del papiloma humano ha dependido, depende y dependerá de la industria que fabrica dichas vacunas (10). Se ignora porqué los gobiernos de los países desarrollados han renunciado a tener un papel activo en el conjunto de la salud sexual, y se reservan sólo el papel pasivo de “pagador” de la vacuna.

Are there clinical trials and independent research that have not been financed or sponsored by the pharmaceutical industry? No, or if so, they are irrelevant.
The bulk of the research on the HPV vaccine has been, is, and will continue to be dependent on the manufacturers of the vaccine. It is unclear why the governments of wealthy countries have declined to take an active role in this area of sexual health services, and instead have assumed merely a passive role as “payor” for the vaccine (10).

11. ¿Se precisa mantener el programa actual de detección precoz del cáncer de cuello de útero? Sí. Los actuales programas de cribaje con la citología (Papanicolau) tienen graves problemas de cobertura y fundamento científico, pero la vacuna no los evita, pues combate sólo dos de los quince virus oncogénicos. No sabemos en qué forma se modificará la sensibilidad y especificidad del cribaje (5,7).
Is it still necessary to continue the current early dectection programs for cervical cancer? Yes.
Current screening programs to detect cervical cancer by cytology (Pap smears) have serious problems in terms of patient access as well as scientific basis, the vaccine doesn’t replace them, as the vaccine only acts against 2 of the 15 oncogenic viruses. We do not know how the specificity and sensibility of screening tests should be modified (5,7).

Bibliografía
Bibliography

Vacuna.org. Calendario de vacunación. Europa. http://www.vacunas.org/index.php?option=com_content&task=view&id=2472&Itemid=336. Consultado el 13 de octubre de 2007.
Gervas J, Pérez Fernández M, González de Dios J. Problemas prácticos y éticos de la prevención secundaria. A propósito de dos ejemplos en pediatría. Rev Esp Salud Pública. 2007;81:345-52.
Starfield B, Hyde J, Gérvas J, Heath I. The concept of prevention: a good idea gone astray? J Epidemiol Community Health. 2008 [in press].
Gérvas J, Starfield B, Heath I. Caution in clinical prevention. Lancet. 2008 [in press].
Markowitz LE, Dunne EF, Saraiya M, Lawson HW, Chessm H, Unger E for the ACIP. Quatrivalent human papilloma virus vaccine. MMWR. 2007;56(RR02): 1-24.
Galceran J, Marcos R, Izquierdo A, Borrás J. Carcinoma invasor y lesiones premalignas del cuello uterino en los registros poblacionales: utilidad y limitaciones. En: Sanjosé S, García A (coordinadoras). Madrid: Sociedad Española de Epidemiología (4ª Monografía); 2006. p. 15-29.
Navarro JA, Bernal PJ, Pérez JJ. Interrogantes en la introducción de la vacuna frente al virus del papiloma humano en los calendarios sistemáticos. Med Clín (Barc). 2007;129:55-60.
EMEA. EPARS for authorised medicinal products. Gardasil. http://www.emea.europa.eu/humandocs/Humans/EPAR/gardasil/gardasil.htm. Consultado el 13 de octubre de 2007.
Hughes JP, Garnett GP, Koutsky L. The theoretical population-level impact of a prophylactic human papilloma virus vaccine. Epidemiol. 2002;13: 361-9.
Sawaya GF, Smith K. HPV vaccination. More answers, more questions. N Engl J Med. 2007;356:1991-3.
Kahn JA, Burk RD. Papillomavirus vaccines in perspective. Lancet. 2007;369:2135-7.
Lippman A, Melnychuk R, Shimmin C, Boscope M. Human papillovirus, vaccines and women’s health: questions and cautions. CMAJ. 2007;177:484-7.
Joura EA, Leodoter S, Hernández-Ávila M, Wheeler CM, Pérez G, Loutsky LA et al. Efficacy or quadrivalent prophylactic human papillomavirus (types 6, 11,16, and 18) L1 virus-like-particle vaccine against high-grade vulvar, and vaginal lesions: a combined analysis of three randomised clinical trials. Lancet. 2007;369:1693-702.
Rambout L, Hopkins L, Hutton B, Fergusson D. Prophylactic vaccination against human papillomavirus infection and disease in women: a systematic review of randomized controlled trials. CMAJ. 2007;177:469-79.
Brisson M, Velde N, Wals P, Boily MC. Estimating the number needed to vaccinate to prevent diseases and death related to human papillomavirus infection. CMAJ. 2007;175:464-8.
Future II Study Group. Quatrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions. N Engl J Med. 2007:356:1915-27.

Fuente: Gervas, J. (2008, June 8). June08. Retrieved Sep. 21, 2008, from http://www.healthyskepticism.org/news/2008/June08.htm.

Prevencion del cancer colorrectal


Pruebas de detección habituales previenen el cáncer colorrectal

MMWR, Apr 14, 2008 18:15:00 GMT

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El cáncer colorrectal es el segundo tipo de cáncer que causa más muertes en Estados Unidos. Este cáncer afecta a hombres y mujeres de todos los grupos étnicos y raciales, pero es más común en las personas mayores de 50 años. El cáncer colorrectal se puede prevenir. Las pruebas periódicas pueden detectar pólipos en el colon que pueden ser retirados antes de convertirse en cáncer. Las personas de 50 años o más, con antecedentes familiares de este cáncer, deben ver al doctor para hacerse prueabas periódicas.

Preventive Medicine and Public Health


Book name: Pretest Self-Assessment and Review : Preventive Medicine and Public Health
Author: Ratelle Sylvie
Publisher: McGraw-Hill Companies, 9th edition
Year: 2000
Pages: 238
ISBN: 0071359621
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La corrección temprana de la criptorquidia se asocia a un menor riesgo de cáncer testicular


Pettersson A, Richiardi L, Nordenskjold A, Kaijser M, Akre O. Age at Surgery for Undescended Testis and Risk of Testicular Cancer. N Engl J Med 2007; 356: 1835-1841.  R   TC (s)   PDF (s)

Introducción

Es conocido que los niños que presentan una criptorquidia tienen un mayor riesgo de presentar un cáncer de testículo (CT) posteriormente, pero se desconoce si se debe a que se trata de testículos anormales de entrada o que la criptorquidia en sí misma es la causa del CT.

Objetivo

Estudiar la relación entre la edad de la corrección quirúrgica de la criptorquidia y el riesgo de desarrollar un CT.

Perfil del estudio

Tipo de estudio: Estudio de cohortes

Área del estudio: Pronóstico

Ámbito del estudio: Comunitario

Métodos

Este estudio se llevó a cabo mediante la relación de los registros suecos de ingresos hospitalarios y de tumores, que incluyen todos los ingresos hospitalarios y tumores del país. Se incluyeron en la cohorte todos los pacientes que habían recibido un diagnóstico de criptorquidia entre 1964 y 1999 a los que se les había practicado una orquidiopexia a una edad <20 años. El periodo de observación se inició a 15 años años de edad o un año después de la orquidiopexia. Se compararon las tasas de incidencia de cáncer testicular observadas con las tasas estandarizadas de la población.

Resultados

La cohorte se constituyó con 16.983 varones que habían sido intervenidos por una criptorquidia. El seguimiento medio fue de 12,4 años. La edad media de la intervención fue de 8,5 años. Se detectaron 56 casos de CT. El número de casos que corresponderían según las tasas de incidencia estandarizadas de la población general sería de 20. A lo largo de los años, la edad de la intervención se fue reduciendo.

La razón de incidencia estandarizada para los que se operaron antes de los 13 años de edad fue de 2,23 (IC95% 1,58 a 3,06) y, para los que se operaron después de esta edad, de 5,40 (CI95% 3,20 a 8,53). La razón de incidencia estandarizada también se redujo con el paso de los años, pero en todos ellos, fue superior para los que habían sido intervenidos antes de los 13 años.

Conclusiones

Los autores concluyen que el tratamiento de la criptorquidia antes de la pubertad disminuye el riesgo de CT.

Conflictos de interés

Ninguno declarado. Financiado por becas del Swedish Cancer Society y el Swedish Research Council, entre otros.

Comentario

La criptorquidia afecta a un 2-5% de los niños varones a término y, a los 12 meses de edad, en un 1% de los niños los testículos aún no han descendido. Estos niños tienen mayor riesgo de desarrollar CT. En un estudio se encontró que aproximadamente un 1,5% de los niños presentaban indicios de CT en el momento de la orquidiopexia, especialmente si presentaban otras malformaciones genitales, los testículos eran intraabdominales o tenían anomalías en el cariotipo. Existen dudas sobre si esta asociación se debe a un efecto deletéreo de la situación ectópica de los testículos o a que se trata de testículos anómalos de entrada. En los casos de cirptorquidia unilateral, en un 20% de los casos los tumores se dan en el testículo con un descenso normal, lo que apoyaría la idea de una anomalía subyacente.

El tratamiento de la criptorquidia se basa en la orquidipexia, con la intención de restaurar la posición correcta de los testículos, preservar la fertilidad y hacer los testículos accesibles a la exploración. En estudios previos, la relación entre la edad a la que se practicó la orquidiopexia y el riesgo de CT han obtenido resultados no concluyentes. En este estudio, los niños en los que se llevó a cabo una orquidiopexia más temprana presentaron un menor riesgo de desarrollar un tumor, lo que apoyaría la idea de que la situación ectópica del testículo podría tener un efecto nocivo sobre el mismo. A la espera de alguna revisión sistemática sobre el tema, los resultados de este estudio irían a favor de un tratamiento temprano del cuadro.

Bibliografía

  1. Cortes D, Visfeldt J, Moller H, Thorup J. Testicular neoplasia in cryptorchid boys at primary surgery: case series. BMJ 1999; 319: 888-889.   TC   PDF
  2. Swerdlow AJ, Higgins CD, Pike MC. Risk of cancer in cohort of boys with cryptorchidism. BMJ 1997; 314: 1507-1511.  R   TC
  3. Herrinton LJ, Zhao W, Husson G. Management of cryptorchism and risk of testicular cancer. Inf Terapéutica del SNS 2003; 157: 602-605.  R   TC   PDF

Autor

Manuel Iglesias Rodal. Correo electrónico: mrodal@menta.net.

Lavarse las manos, una 'medicina' barata y eficaz contra las epidemias


Se estima que con esta sencilla medida se evitaría el contagio de enfermedades respiratorias y gastrointestinales en el 40% de los casos

Lavarse las manos, una ‘medicina’ barata y eficaz contra las epidemias

Un teclado compartido albergaba el norovirus que ha ocasionado 103 casos de gastroenteritis en un colegio de Washington (Estados Unidos). Si el primer infectado se hubiese lavado bien las manos no se habría desatado la epidemia, revelaba la semana pasada el Centro para la Prevención y Control de Enfermedades de Atlanta (CDC, en sus siglas en inglés), que contaba así con nuevos argumentos para sus campañas nacionales de promoción de un lavado de manos correcto en el ámbito doméstico, habituales en Estados Unidos y casi inexistentes en Europa y España. Según el CDC, son necesarios al menos entre 15 y 20 segundos bajo el agua corriente y con abundante jabón para eliminar de forma óptima los gérmenes. En su defecto, se recomienda el uso de toallitas con alcohol o geles desinfectantes como los que se emplean en el medio hospitalario.
Naiara Brocal Carrasco. naiara.brocal@unidadeditorial.es 21/01/2008

“Las manos se encuentran en continuo contacto con otros objetos y nosotros mismos, y en ese circuito se transmiten todo tipo de virus, bacterias, parásitos u hongos (ver gráficos)”, advierte José Ramón Azanza, del Servicio de Enfermedades Infecciosas y Microbiología Clínica de la Clínica Universitaria de Navarra.

“Si no se hace bien y se permiten reservorios en las uñas, se convierten en vehículo de transmisión de enfermedades”.

Cambiar actitudes

El responsable de Vigilancia Epidemiológica del Departamento de Sanidad del Gobierno Vasco, Miguel Ángel García Calabuig, expone que el lavado de manos es la primera medida que inculcan las autoridades sanitarias cuando existe un brote infeccioso, aunque reconoce que habría que hacer un esfuerzo mayor para llegar a los hogares. “No es fácil cambiar actitudes, y el problema de las campañas sanitarias es que con el tiempo pierden eficacia”.

El experto estima que se ha infravalorado la higiene desde la aparición de los antibióticos, que, lejos de acabar con las enfermedades infecciosas, y sin negar sus grandes beneficios en términos de morbimortalidad, están generando otras multirresistentes.

La higiene de las manos se erige en una medida eficaz y barata para contener infecciones, terreno en el que los países anglosajones llevan ventaja gracias a una tradición en la realización de campañas sanitarias y estudios sobre este asunto y que estiman que podrían reducir hasta un 50 por ciento las infecciones gastrointestinales, un 40 las respiratorias, y en menor proporción las dermatológicas.

Ante la crisis

Precisamente, el Departamento de Sanidad del Reino Unido ha puesto en marcha una campaña invernal de promoción del lavado de manos para reducir el contagio de gripe y resfriados. La importancia de la higiene para contener epidemias respiratorias se puso de manifiesto con la crisis sanitaria desatada por el síndrome respiratorio agudo severo (SRAS).

Por otra parte, expertos en higiene estadounidenses y británicos publicaban en diciembre en American Journal of Infection Control (AJIC) un informe en el que concluyen que el inculcar un correcto lavado de manos es la medida de salud pública más efectiva y barata contra el contagio de gripe y gastroenteritis, e incluso infecciones por Staphylococcus aureus resistente a meticilina (MRSA, en sus siglas en inglés), salmonela o Clostridium difficile, bacteria cada vez más visible fuera de hospitales. Los expertos resaltan su relevancia ante la amenaza de la gripe aviar.

La infección por gripe y resfriado se puede producir a través de las manos tras tocar objetos contaminados y con sólo frotarse los ojos o la nariz. Las manos están a menudo implicadas en la transmisión de enfermedades gastrointestinales en un proceso favorecido por la alta perdurabilidad de estos patógenos (ver cuadro). “Casi el 85 por ciento de gastroenteritis invernales se produce por norovirus, que pueden permanecer en superficies durante días”, apunta Vicente Baos, coordinador del Grupo de Utilización de Fármacos de la Sociedad Española de Medicina Familiar y Comunitaria (Semfyc). En el grupo de dermatológicas, Baos destaca la conjuntivitis por adenovirus, también frecuente en esta época y “en las que se debe insistir en la importancia del lavado de manos antes y después de aplicar el tratamiento”.

Y es que es importante lavarse las manos en los momentos precisos: después de sonarse la nariz o coger pañuelos contaminados, tras ir al baño o antes de cocinar. En situaciones de alto riesgo, como tras manipular carne cruda o ante una epidemia de gastroenteritis, los autores del informe recogido por AJIC aconsejan usar preparados con alcohol. Una de ellas, Carol O’ Boyle, de la Escuela de Enfermería de la universidad estadounidense de Minesota, resalta la importancia de los sustitutivos de jabón y agua cuando no se está en casa y se utiliza el transporte público, en el supermercado, en la oficina o el restaurante.

Otras medidas

El informe se publica poco después de que un estudio aparecido en noviembre en British Medical Journal concluía que el lavado regular de manos y el uso de máscaras, guantes y gorros es más eficaz que los medicamentos para prevenir el contagio del SRAS o la gripe. Para el jefe de Medicina Preventiva del Hospital La Paz, de Madrid, Juan García Caballero, el lavado de manos es una medida eficaz para prevenir infecciones comunitarias pero no es la única. El cumplimiento de los calendarios vacunales, la contención respiratoria (taparse la boca al toser o estornudar) y la preparación y refrigerado correcto de alimentos son otras medidas sencillas y eficaces para prevenir los contagios, de máxima vigencia en los meses fríos.

Otros articulos relacionados:

En Riesgo de Contagio, un Beso de Cortesía Puede Ser Menos
Noticias Ciencia y Tecnologia –
Todos hemos escuchado a personas de nuestro entorno decirnos que no van a besarnos porque están resfriadas. Sin embargo, un nuevo estudio advierte que puede