Evidence Based Medicine & HTA

Health Techonology Assessment and Safety Patient

2012-02-23T12:45:00.000-08:00

Health Information Technology and Patient Safety

Efectividad de la artroscopia de rodilla

2012-02-14T16:44:00.000-08:00

Introducción: La artroscopia es un procedimiento quirúrgico mínimamente invasivo que se utiliza para el abordaje de patologías intraarticulares. Aunque el abordaje artroscópico de la rodilla es en la actualidad la técnica quirúrgica más difundida para el tratamiento de diferentes patologías de la misma existe, no obstante, controversia sobre el tema.

Objetivo: Con este informe se trata de proporcionar a los profesionales sanitarios una revisión global sobre la eficacia y la seguridad de la artroscopia de rodilla, basada en la mejor evidencia científica disponible en la actualidad.

Los principales aspectos que se abordan en este documento están relacionados con el uso de la artroscopia como procedimiento terapéutico en diversas patologías de rodilla. Estas patologías incluyen problemas agudos, crónicos, afecciones propias de la articulación o en el seno de enfermedades sistémicas. Esta revisión no aborda evaluaciones de otras intervenciones en las cuales la artroscopia no sea el tema principal del estudio.

Para operativizar el trabajo se plantearon las siguientes preguntas:

• ¿Cuál es la eficacia de las distintas variantes técnicas artroscópicas?

• ¿Cuál es la eficacia de la artroscopia en la patología osteocondral?

• ¿Cuál es la eficacia de la artroscopia en la patología de menisco?

• ¿Cuál es la eficacia de la artroscopia en la patología ligamentosa?

• ¿Cuál es la eficacia de la artroscopia en la patología sinovial?

• ¿Cuál es la eficacia de la artroscopia en los traumatismos agudos?

• ¿Cuál es la eficacia de la artroscopia postartroplastia?

• ¿Cuál es la calidad de vida de las personas sometidas a tratamiento

artroscópico de rodilla?

Metodología: Se llevó a cabo una búsqueda exhaustiva en las siguientes bases de datos: Biblioteca Cochrane Plus 2006, número 1, MEDLINE (1964-2006; acceso mediante PubMed) y EMBASE (Dialog Star; 1974-2006).

Adicionalmente se realizó una búsqueda en el buscador de literatura médica TRIP Database y diferentes agencias internacionales de evaluación de tecnologías. En España, se consultaron de forma adicional, las bases de datos de la Agencia de Evaluación de Tecnologías Sanitarias del Instituto de Salud Carlos III, y las de las Agencias Catalana y Vasca de Evaluación de Tecnologías.

Dada la escasez de revisiones sistemáticas, guías de práctica clínica y ensayos clínicos en el campo de la cirugía se consideraron todo tipo de estudios, que hubiesen sido publicados entre 1964 y 2006 (incluyendo estudios de cohortes, de casos y controles, de corte transversal y serie de casos). El idioma de publicación debía ser el inglés, el francés o el español.

Para cada tema, se describieron las revisiones sistemáticas, guías de práctica clínica y ensayos clínicos siguiendo los criterios estandarizados de extracción de datos y de valoración de la validez interna propuestos por el Scottish Intercollegiate Guidelines Network. En las ocasiones en las que fue necesario evaluar estudios de cohortes y diseños de menor nivel de evidencia, se resumió la información siguiendo el mismo procedimiento descrito para los otros diseños y evaluando su calidad metodológica de manera similar. Una vez analizada la evidencia, para cada apartado temático se redactó

un texto resumen de los artículos incluidos para su actualización, así como un

conjunto de valoraciones o conclusiones derivadas del conjunto de la evidencia. Para establecer los niveles de evidencia de las diferentes intervenciones evaluadas en este informe, se utilizó la propuesta del Centro de Medicina Basada en la Evidencia de Oxford. A partir de la valoración consensuada del equipo de trabajo se ha clasificado la calidad global de la evidencia para cada intervención como de calidad alta, moderada o baja. La evaluación de la calidad global de la evidencia para cada variable de resultado ha sido llevada a cabo teniendo en cuenta tanto la el diseño de los estudios, la validez interna, la

evaluación de si la evidencia es directa o indirecta, la consistencia y la precisión de los resultados así como otros factores como el posible sesgo de publicación.

Conclusiones: La evidencia disponible respecto de la eficacia terapéutica de la artroscopia de rodilla es escasa y de baja calidad metodológica, situación que dificulta la generación de cualquier tipo de recomendación salvo la de la necesidad de realizar estudios comparativos de buena calidad para aclarar la incertidumbre actual.

Es importante señalar que todas las técnicas artroscópicas requieren un riguroso y correcto aprendizaje ya que tanto la duración como el número de complicaciones disminuyen con la experiencia.

- Técnica de la artroscopia

El uso del manguito neumático mejora la visión del campo operatorio pero no existen diferencias en cuanto a complicaciones o éxito de la intervención. (Calidad moderada). El uso de anestésico intraarticular como bupivacaina reduce el dolor postoperatorio, pero esta reducción es moderada y de corta duración (Calidad alta). Por otra parte, la

utilización del láser parece ser ventajoso para el tratamiento de la condromalacia pero no ofrece ninguna ventaja adicional en otras patologías de rodilla tratadas con técnica artroscópica (Calidad moderada).

- Eficacia terapéutica de la artroscopia en:

Patología osteocondral

-Artrosis

El lavado con desbridamiento no está indicado en ninguna etapa de la artrosis de rodilla como tratamiento para aliviar el dolor y mejorar la funcionalidad. Ambos procedimientos

podrían ser efectivos en pacientes con síntomas mecánicos. El desbridamiento solo también podría ser efectivo para el compartimiento medio de rodilla (Calidad alta).

El desbridamiento artroscópico comparado con lavado artroscópico mejora el dolor en pacientes con enfermedad degenerativa del cóndilo femoral medio. El desbridamiento

artroscópico también puede ser utilizado para manejar síntomas mientras se espera la realización de una osteotomía o la sustitución de la articulación de la rodilla.

Los peores resultados se producen en aquellos pacientes con artrosis tricompartimental, síntomas de enfermedad de más de cinco años y limitación o déficit de movilidad mayor

de diez grados previo a la cirugía (Calidad baja)

- Patología del cartílago

El trasplante autólogo de condrocitos no es superior a otras técnicas en el tratamiento de las lesiones condrales de la rodilla. La técnica de microfractura puede ser útil para el

tratamiento de osteonecrosis de cualquier origen (Calidad baja).

Patología de menisco

Para la reparación de meniscos lesionados, la artroscopia no fue superior como técnica comparada con la cirugía abierta en resultados a corto plazo en estudios realizados

hace 30 años (Calidad alta). La meniscectomía parcial es un procedimiento eficaz en aquellos pacientes con lesión meniscal central. Produce menos cambios degenerativos

comparada con la resección total, pero provoca pérdida importante de cartílago. La alternativa de usar sutura artroscópica con canales de acceso en lugar de

meniscectomía parcial, favorece la conservación del menisco y su función a largo plazo(Calidad mediana).

Después de la reparación de menisco, no es necesario restringir la actividad o indicar un plan de ejercicios específico (Calidad baja).

Patología ligamentosa

El tratamiento artroscópico de las lesiones de los ligamentos de la rodilla (ligamento cruzado anterior, ligamento cruzado posterior) no cuenta con evidencia suficiente para afirmar que esta técnica es superior al tratamiento conservador (Calidad alta). El tratamiento quirúrgico artroscópico del ligamento cruzado anterior favorece la estabilidad de la rodilla a corto y medio plazo (Calidad baja).

Patología sinovial

Para el síndrome de la plica (pliegue) sinovial, la división de la misma mediante artroscopia es efectiva para el alivio de los síntomas (Calidad alta). En la artritis reumatoide la sinovectomía por vía artroscópica es más efectiva que la cirugía a cielo abierto para mejorar la sintomatología que la enfermedad produce en la articulación de la rodilla (Calidad baja).

Traumatismos agudos.

En los traumatismos agudos de rodilla, el desbridamiento de la articulación mediante artroscopia permite detectar anomalías intraarticulares subyacentes, con menor dolor

postoperatorio, menor tiempo de ingreso, mejor cosmética y es un método seguro y efectivo. La artroscopia puede realizarse de forma precoz o tardía (tres semanas).

Cuando el traumatismo lesiona de manera importante los ligamentos o el menisco se necesita realizar una artroscopia en la etapa aguda. (Calidad baja)

Artroscopia posterior a artroplastia

La artroscopia posterior a la cirugía de reemplazo es un procedimiento eficaz en la mejoría de dolor y funcionalidad y seguro en cuanto a no producir subluxaciones,

desplazamientos de la rótula, inestabilidad o infecciones (Calidad baja).

- Eficacia de la artroscopia en la mejoría de la calidad de vida

No hay diferencias en la calidad de vida a largo plazo (dos años y más) medida en términos de dolor y capacidad funcional cuando se compara el lavado y desbridamiento artroscópico con el placebo o no intervención en artrosis de rodilla (Calidad alta). No existe suficiente evidencia para determinar si la calidad de vida a largo plazo es mejor

en la meniscectomía parcial artroscópica que en la meniscectomía parcial o total a cielo abierto (Calidad baja). No existe suficiente evidencia para determinar si el tratamiento quirúrgico de las lesiones de ligamentos mejora la calidad de vida en mayor medida que el

tratamiento conservador (Calidad baja).

Fuente: Agencia de Evaluacion de Tecnologia Sanitaria de Andalucia. Informe Completo en PDF.

Valoracion de los ensayos clinicos: CONSORT

2012-02-08T10:59:00.000-08:00

La calidad de los ensayos clinicos aleatorizados (ECA) es motivo de preocupación debida a la baja calidad que presentan los mismos aún en revistas altamente reconocidas en el campo médico. En este sentido un grupo de trabajo se ha dedicado a crear herramientas para poder evaluar mejor este tipo de ensayos, de las cuales una de la mas reconocidas es CONSORT. La encuesta puede ser encontrada en multiples documentos y tambien en su website donde puede leerse en varios idiomas. Inicialmente se originó con 22 preguntas y un algoritmo que no debieran faltar en ningun ensayo clinico, asi como tambien se agregó en el ultimo año preguntas referidas a la seguridad de los medicamentos, ya que este tipo de ensayos no es justamente el más adecuado para valorar efectos que pueden aparecer raramente en este tipo de estudios, pero que luego en la practica clinica estos efectos adversos se ven magnificados.

Ejemplo de ello es el Rofecoxib cuyos datos fueron ocultados por MSD, o los efectos de la Rosuvastatina que es la unica estatina que mostró ya en ensayos de fase III problemas de seguridad, y aún asi fue aprobada por la FDA y la EMEA.

Publicamos aqui en el idioma de Cervantes, algunos de los articulos mas relevantes de este abordaje.

Consort I

Consort II

Multiples criticas se hacen a este tipo de trabajos, que se han convertido en el paradigma de la investigacion cientifica. Solo por señalar alguno, que quizas creemos el mas relevante, es el hecho que cuando más controlado esté el estudio, más se acerca a condiciones experimentales (que en definitiva es lo que buscan los investigadores), pero con ello se pierde también validez externa, ya que solo será válido para una población que sea tan igual a ella misma, en tiempo, espacio y personas, que aun repetido en el mismo lugar , pudiera perder su validez externa. Este hecho no menor en la investigación clinica da lugar a inferecias de caracter inductivo, es decir se universaliza un conocimiento particular, y luego es promocionado como deductivo (es decir como premisa verdadera que es válida en todo tiempo y lugar), dando lugar a una clausura operacional, y un sesgo que no admite discusiones. Agregado a esto que la mayoria de estos estudios son realizados en ambitos hospitalarios, vale la pena preguntarse en cuanto son aplicables a nuestros pacientes, y aún así si reconocer que otros sesgos que iremos comentando se dan en este tipo de trabajos. Un desafio para la ciencia médica, que ha clausurado la apertura a diseños mas abiertos, de caracter cuali-cuantitativos, y aún expulsado la lógica de su material y metodos, la cual es reemplazada por la matematización de hechos que dificilmente puedan ser aplicados en las ciencias biológicas, donde la linealidad es extraña, la distribución normal una forma rara de ver en nuestra consulta, y nuestros pacientes en poco se parecen a aquellos que los estudios refieren. Algo asi como estudiar veterinaria en un zoo, y sólo aprender sobre elefantes, jirafas y pandas, para luego salir a la práctica cotidiana a tratar otro tipo de especies. Visto asi, hasta suena ridiculo, pero a mi humilde entender no deja de ser cierto.

Integrated management of type 2 diabetes mellitus and depression treatment to improve medication adherence: a randomized controlled trial

2012-01-24T20:51:00.000-08:00

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Bogner HR, Morales KH, de Vries HF, et al. Integrated management of type 2 diabetes mellitus and depression treatment to improve medication adherence: a randomized controlled trial. Ann Fam Med. 2012 Jan;10(1):15-22. (Original) PMID: 22230826

PURPOSE Depression commonly accompanies diabetes, resulting in reduced adherence to medications and increased risk for morbidity and mortality. The objective of this study was to examine whether a simple, brief integrated approach to depression and type 2 diabetes mellitus (type 2 diabetes) treatment improved adherence to oral hypoglycemic agents and antidepressant medications, glycemic control, and depression among primary care patients. METHODS We undertook a randomized controlled trial conducted from April 2010 through April 2011 of 180 patients prescribed pharmacotherapy for type 2 diabetes and depression in primary care. Patients were randomly assigned to an integrated care intervention or usual care. Integrated care managers collaborated with physicians to offer education and guideline-based treatment recommendations and to monitor adherence and clinical status. Adherence was assessed using the Medication Event Monitoring System (MEMS). We used glycated hemoglobin (HbA(1c)) assays to measure glycemic control and the 9-item Patient Health Questionnaire (PHQ-9) to assess depression. RESULTS Intervention and usual care groups did not differ statistically on baseline measures. Patients who received the intervention were more likely to achieve HbA(1c) levels of less than 7% (intervention 60.9% vs usual care 35.7%; P <.001) and remission of depression (PHQ-9 score of less than 5: intervention 58.7% vs usual care 30.7%; P <.001) in comparison with patients in the usual care group at 12 weeks. CONCLUSIONS A randomized controlled trial of a simple, brief intervention integrating treatment of type 2 diabetes and depression was successful in improving outcomes in primary care. An integrated approach to depression and type 2 diabetes treatment may facilitate its deployment in real-world practices with competing demands for limited resources.

Niveles de Evidencia

2011-11-13T20:31:00.000-08:00

Geometría de la evidencia

2011-11-10T14:13:00.000-08:00

Pediatria Basada en la Evidencia por Ricardo Alexandre

En las últimas semanas, los asistentes al 19 Cochrane Colloquium, hemos estado contando en este blog algunos de los muchos momentos interesantes a los que tuvimos el gusto de asistir.

Una conferencia muy impactante fue la que pronunció el Profesor Ioannidis, y que un buen amigo, Peter Gill, canadiense afincado en Oxford (UK) y muy relacionado con el Center for Evidence Based Medicine, nos cuenta en su blog, y que con su permiso traducimos, ya que cualquier otra cosa sería repetir lo que él tan claramente expone el 27 de octubre:

“La semana pasada, en el 19 Cochrane Colloquium en Madrid, el Profesor John Ioannidis dela Universidad de Stanford, dio una charla fascinante sobre la geometría de la evidencia. De entre los cientos de artículos que ha publicado, su artículo de 2005 sobre “Why most published research findings are false”, es el artículo técnico más descargado de la revista PLos Medicine con más de 400 000 visitas. Sin duda, este autor es líder en abordar temas polémicos sobre investigación biomédica.

En esta conferencia, recomienda una visión amplia de la investigación utilizando redes de meta-análisis. Los meta-análisis tradicionales son útiles para comparar dos intervenciones, o una intervención con placebo. Pero, ¿qué ocurre cuando hay docenas de ensayos clínicos aleatorizados sobre muchos fármacos diferentes para la misma enfermedad? Por ejemplo, hay 68 antidepresivos para elegir, ¿cómo puede el médico decidir cuál es el más eficaz? De hecho, Ioannidis opinaba que probablemente sería una estupidez depender de un solo meta-análisis.

Entremos en las redes. Ioannidis ha dirigido el desarrollo de múltiples meta-análisis de tratamientos o redes de meta-análisis. En su forma mas simple, la red dibuja todas las intervenciones para una dolencia conocida en un enrejado o diseño tipo celosía. El enrejado muestra los ensayos relevantes para una cierta intervención e ilustra cómo conectan (o no conectan) unos con otros. El patrón de las comparaciones es la “geometría de la red de tratamientos”.

Por ejemplo, se han realizado 69 ensayos para el abandono del hábito tabáquicocomparando reemplazamiento con nicotina con no tratar, pero cero ensayos comparando reemplazamiento con nicotina con el fármaco vareniclina (Champix). Para tomar una decisión informada, los clínicos necesitan información sobre comparación de tratamientos.

Además, si miramos a la financiación de los ensayos clínicos, encontramos que las comparaciones uno-a-uno de fármacos de distintas compañías son muy poco frecuentes. De hecho, se pueden encontrar “auto-bucles” que muestran que la mayoría de los ensayos financiados por la industria abordan un único fármaco propiedad de la compañía. Peor aún, cuando dos compañías farmacéuticas financian el mismo ensayo, no se debe a cooperación altruista sino normalmente a co-propiedad de los mismos productos.

Aunque las redes de meta-análisis ofrecen una imagen más amplia que los meta-análisis tradicionales, combinan un gran número de ensayos y comparaciones en un solo artículo académico, lo cual no es bueno para el CV de los investigadores, según Ioannidis. La estructura actual anima a la realización de revisiones sistemáticas definidas de forma muy concisa y de ensayos clínicos que demuestren eficacia y no anima a alejarse como un zoom para tener una visión global. Las redes, aunque proporcionan un corte transversal de un tema clínico en un punto dado en el tiempo, permiten ver la base de la evidencia actual y poder identificar dónde faltan conexiones.

Volviendo al ejemplo anterior del abandono del hábito tabáquico, necesitamos ensayos que comparen reemplazamiento de nicotina con vareniclina (Champix), no otro estudio que muestre que el reemplazamiento de nicotina comparado con placebo es eficaz. Pero el problema es que esto último es fácil de publicar con un gran tamaño del efecto, pero lo primero probablemente no mostrará diferencias y no producirá titulares en la BBC”.

Surgical correction of hallux valgus using minimal access techniques

2011-10-21T13:17:00.000-07:00

Summary

The National Institute for Health and Clinical Excellence (NICE) has issued full guidance to the NHS in England, Wales, Scotland and Northern Ireland on Surgical correction of hallux valgus using minimal access techniques.

The guidance was considered for reassessment in October 2011 and it was concluded that NICE will not be updating this guidance at this stage. However, if you believe there is new evidence which should warrant a review of our guidance, please contact us via the email address below.

Description

Hallux valgus is a deformity of the big toe. The big toe tilts outwards, crowding the smaller toes, and a bony lump (called a bunion) appears on the inside of the foot.

Under local or general anaesthesia, one or more small cuts are made to insert bone-cutting instruments. These are used to remove the bunion and to divide one or more of the bones of the front of the foot. The divided bones may need to be stabilised with wires, screws or plates. The aim is to correct the tilting of the big toe. The operation is monitored by X-rays or an endoscope (a telescope for looking inside the body). Compared with standard (open) surgery, this procedure uses smaller cuts to the foot and X-rays or endoscopy to see inside the foot.

OPCS4.6 Code(s):

The OPCS-4 codes would depend on the exact procedure performed; although it is not possible to classify the size of incisions in OPCS-4, if an endoscope is utilised during the procedure or if some form of image control is required, then relevant additional Chapter ‘Y’ codes are assigned.

_{The NHS Classifications Service of NHS Connecting for Health is the central definitive source for clinical coding guidance and determines the coding standards associated with the classifications (OPCS-4 and ICD-10) to be used across the NHS. The NHS Classifications Service and NICE work collaboratively to ensure the most appropriate classification codes are provided. www.connectingforhealth.co.uk/clinicalcoding}

Details

Arrangement:

Special

Topic area:

Musculoskeletal
Surgical procedures

Specialty:

Trauma and orthopaedic surgery

Specialist advice sought from:

British Orthopaedic Association (BOA)

British Orthopaedic Foot & Ankle Society (BOFAS)

Date notified to NICE:

12 febrero 2009

Provisional consultation date:

Winter 2009

Guidance issue date:

24 febrero 2010

Contact details:

Contact NICE about this project

ip@nice.org.uk

Technical lead
(for procedure specific enquiries or comments)

Nicola Sloan

Contact Address:

Interventional Procedures Programme
National Institute for Health and Clinical Excellence
MidCity Place
71 High Holborn
London
WC1V 6NA

Links:

	IPG332 Surgical correction of hallux valgus using minimal access techniques: guidance (web format)	10 February 2011
	IPG332 Trin bynionau gan ddefnyddio llawdriniaeth drwy doriadau bach: deall canllawiau NICE (fformat MS Word)	08 April 2010
	IPG332 Surgical correction of hallux valgus using minimal access techniques: guidance	24 February 2010
	IPG332 Surgical correction of hallux valgus using minimal access techniques: understanding NICE guidance	24 February 2010
	IPG332 Surgical correction of hallux valgus using minimal access techniques: understanding NICE guidance (MS Word version)	24 February 2010
	Surgical correction of hallux valgus using minimal access techniques: audit support	24 February 2010
	Surgical correction of hallux valgus using minimal access techniques: consultation comments	24 February 2010
	Surgical correction of hallux valgus using minimal access techniques - Overview	24 February 2010
	Surgical correction of hallux valgus using minimal access techniques (interventional procedures overview)	21 October 2009
	Surgical correction of hallux valgus using minimal access techniques (interventional procedures consultation)	20 October 2009

This page was last updated: 20 October 2011

Routine HIV Screening — What Counts in Evidence-Based Policy?

2011-10-07T13:37:00.000-07:00

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Routine HIV Screening — What Counts in Evidence-Based Policy?

Ronald Bayer, Ph.D., and Gerald M. Oppenheimer, Ph.D., M.P.H.

N Engl J Med 2011; 365:1265-1268October 6, 2011

Article
References: In January 2011, the President's Advisory Council on HIV/AIDS called on the U.S. Preventive Services Task Force (USPSTF) to reconsider its 2005 determination that the scientific evidence did not justify routine testing for human immunodeficiency virus (HIV) in adolescents and adults in the general U.S. population. In July, the Institute of Medicine issued a report calling for annual HIV screening in all sexually active women. These are the most recent episodes in a struggle that began in 2006, when the Centers for Disease Control and Prevention (CDC) recommended routine HIV testing. Normally, USPSTF decisions receive little attention. Sometimes, however — for example, when the Task Force recommended against routine mammography for women in their 40s — there is political fallout, and observers question what kind of evidence should count and who should make those determinations. The battle over HIV screening, though less public and heated than the mammography debate, demonstrates how the same evidence can lead the country's top public health agency and the body charged by the government with providing scientifically grounded recommendations on clinical preventive interventions to reach dramatically different conclusions.
The USPSTF reflects the legacy of British clinician Archie Cochrane, who criticized medicine for failing to systematically weigh clinical and epidemiologic evidence in making health care decisions. Established in 1984 and sponsored by the Agency for Health Care Research and Quality since 1998, the Task Force evaluates clinical preventive services on the basis of systematic reviews of empirical evidence, determining the magnitude of benefits and harms and issuing grades ranging from A, strongly recommended, to D, not recommended. Capturing the Task Force's ethos, Mark Helfand of the Oregon Evidence-based Practice Center said, “It is never rational to say we must do something [now] because it will take too long to get the evidence. Such actions time and again have been wrong.”
In 2005, the Task Force concluded that although “targeted [HIV] screening misses a substantial proportion of HIV positive patients . . . universal screening would result in large numbers of patients screened for each clinical outcome prevented.”1 Regarding the potential effects of identifying many more people who were unaware of being HIV-positive, the Task Force declared, “Despite evidence that knowledge of HIV positive status reduces some high risk behaviors, there is insufficient evidence with which to accurately estimate the effects on transmission.” Given the potential benefits and harms associated with HIV diagnosis, “including fears of rejection, abandonment, verbal abuse and physical assault,” the Task Force gave general HIV screening a C rating, indicating no recommendation for or against. By stating that individual physicians should determine whether to test, the Task Force rejected the notion of making HIV testing routine practice.
In a published exchange encapsulating the ensuing debate about what evidence regarding HIV testing should be required for changing public policy, a group of clinicians with expertise in AIDS wrote that the benefits of expanding routine HIV testing were “unmistakable.”2 Knowledge of infection provided an opportunity to prevent transmission. Claiming that the potential harms of HIV screening were “minimal,” they argued that the risks did not warrant the withholding of testing. Pointing to current practices' failure to meet the public health and clinical challenges posed by HIV, they concluded, “We cannot allow ineffective testing policies to be perpetuated when experience demonstrates that change is required.”
The chair of the Task Force responded by reemphasizing the burdens of testing for individual patients and clinicians and declaring that as many as 11,000 non–high-risk patients would have to be screened over 3 years to prevent one clinical progression to death. Given the limited duration of primary care visits and what he characterized as the very small likelihood that “any one clinician would provide health benefits to an otherwise undetected seropositive patient,” he concluded that “the physician should consider whether this time might be better spent providing other preventive services that carry the potential to improve outcomes for more patients.”
In September 2006, the CDC issued new recommendations for routine screening that differed sharply from those of the Task Force.3 Haunted by the persistent failure to diagnose HIV in the 250,000-plus people in this country who are infected but unidentified (see tableEstimated Number of People in the United States 13 Years of Age or Older Living with HIV Infection and Number and Percentage Whose HIV Infection was Undiagnosed, 2008.), and on the basis of its own data analysis, the CDC concluded that the public health benefit of reduced transmission justified a departure from its own prior guidance. In fact, it asserted that infected people who were ignorant of their status were a public health hazard, contributing disproportionately to HIV's spread. Citing a recent meta-analysis, the CDC found evidence that people who were aware of their HIV infection substantially curtailed their high-risk behaviors.
The crafters of the new recommendations rejected the Task Force analysis, arguing that an analysis of risk and burden focused on each individual screened ignores significant likely benefits at the population level. The question was what course to pursue when evidence did not meet the most exacting scientific standards. Not taking action, permitting an ineffective policy to persist, was in fact an action. As Bernard Branson of the CDC Division of HIV/AIDS Prevention noted, “The Task Force has the luxury of making no recommendation for or against. The CDC does not really have that option.”
Although the USPSTF usually doesn't revisit its determinations for 5 years, considerable pressure and claims about new evidence led to a “focused update” in April 2007.4 Yet it didn't modify the earlier conclusion.
After examining the nature of the evidence used by the CDC and what it considered methodologic flaws in relevant studies, the USPSTF concluded that the CDC had overstated routine HIV testing's potential effects on transmission. The Task Force also acknowledged the difficulty of obtaining the evidence it deemed crucial: “Studies directly linking screening to decreased rates of transmission would require very large populations with long duration of follow up and are difficult to perform. Not surprisingly no such studies have been published since [the] 2005 evidence synthesis was completed.”
And there the issue remained, despite a 2009 analysis by the American College of Physicians and the HIV Medicine Association supporting the CDC recommendation for routine testing.5 Ironically, what rekindled consideration in 2010 was not new evidence, but the passage of the Affordable Care Act (ACA), which requires health plans to cover preventive services, without charge to patients, if they've received an A or B rating from the USPSTF. Routine HIV screening would thus remain uncovered. In response to that ACA requirement, the Institute of Medicine Committee on Preventive Series for Women recommended that annual HIV screening be included among covered services. Furthermore, 2009 recommendations by the U.S. Public Health Service that antiretroviral therapy be initiated earlier underscored the clinical importance of identifying persons with asymptomatic HIV infection, and in 2011, the HIV Prevention Trials Network's HPTN052 trial demonstrated the powerful effect of therapy on transmission rates.
The Task Force is revisiting its 2005 determination and may reach a decision by the end of 2011. But this saga underscores a broader matter of critical importance to anyone committed to evidence-based practice in medicine and public health. What is from one perspective methodologic rigor may be viewed by others with public health responsibilities as methodologic zealotry. An emphasis on the importance of contextual flexibility is to some an invitation to perilous inconsistency.
Public health practitioners confront the challenge of choosing policies to pursue in the face of uncertainty. Such decisions must take account of the severity of the potential harms from action or inaction. Certainly, such determinations require a strong evidence base, but they will be different for those whose first priority is scientific exactitude and those who focus on making policy in the context of public health, where a precautionary perspective mandates action to prevent foreseeable harms, even when the evidence does not meet the most rigorous demands of science.
Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
This article (10.1056/NEJMp1108657) was published on September 21, 2011, at NEJM.org.
SOURCE INFORMATION
From the Center for the History and Ethics of Public Health, Department of Sociomedical Sciences, Mailman School of Public Health, Columbia University, New York.

Interpreting Confidence Intervals and Grading Recommendations

2011-09-14T22:49:00.000-07:00

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Source: Evidenceinmedicine

My previous post, though not really intended to be focused on p values, led to a long and interesting discussion on the issue by Revere.
Revere commented that it wasn't so clear whether I was writing as a frequentist or a Bayesian. In reality I'm a consumer of biostatistics, not a statistician. For me, the issue is pretty simply to try to know whether a given result I'm seeing is true.
Although I wrote about this in my last post I didn't frame it in exactly this way: the problem with p values is that I want to know how likely it is that the result I'm seeing is correct, while the p value tells me how unlikely it is that I would be seeing a given result if the null hypothesis were true. This is similar to the problem with knowing the sensitivity and specificity of a test, when what you really want to know is the positive predictive value (how likely is it that the patient has the disease now that the test has come back positive?).
The academic medical world started hearing a lot about using confidence intervals in preference to p values 15 or 20 years ago, and I think that led to many doctors concluding that confidence intervals solve this basic p value problem. Confidence intervals have some real benefits compared with p values, but this is not one of them. To look at this, we need to try to understand what a CI means.
Again using the HIV vaccine example from my last post, we can look at the same parameter that had a p value of 0.04, but now examine the point estimate of efficacy (31.2%) and its 95% CI (1.1 to 52.1%). What is it that has a 95% chance of being true, given that CI of 1.1 to 52.1%?
However tricky p value interpretation is for physicians, understanding the meaning of this CI is much worse. I've almost never heard a physician able to correctly interpret the meaning of such a CI when put on the spot with the above question. When trying to teach the interpretation I repeatedly get told there must be a simpler way to communicate the idea. Given my years of failure at this, I have little hope that this post will adequately clarify things for most readers, so if others who teach this have found a way that works to explain it, please write!
All we can really say about that CI is that (excluding any problems with the design or performance of the trial) if we performed the same study 100 times and calculated 95% CIs each time, we would expect that 95 of the 100 CIs formed in this way would include the true point estimate of vaccine efficacy.
Note that just as with p values, this isn't what we want to know: we want to know how likely it is that the true value is inside the particular CI that we are looking at, but that isn't what the CI actually tells us.
However, despite recognizing what the CI really does and does not tell us, consumer of biostatistics that I am, I (and others) approach CIs operationally: we choose to interpret the CI as a range of values with which the data are reasonably compatible, and to interpret values outside the CI as reasonably incompatible with the data. So, other things being equal, I would say that a vaccine efficacy of 5% was compatible with the results of the NEJM study, while a vaccine efficacy of 60% was not. This does not mean that I think the study has excluded the possibility of the vaccine having 60% efficacy, just that this would be unusual under the plays of chance.
This operational definition works as I decide how to write recommendations about whether to administer such a vaccine. If the vaccine truly had an efficacy of 31% I would likely recommend wide use in high risk patients. If the high end of the CI were true (52% efficacy), I might recommend universal vaccination. If the low end were true (1% efficacy) I would probably recommend leaving it on the shelf. Looking at this, I can quickly realize that if this trial were the only information I had about vaccine efficacy then I have inadequately precise data to support whatever recommendation (or set of recommendations) I might want to make about administering HIV vaccine.
If I were using the GRADE scheme for grading such recommendations, I might have started with the assumption that I had high quality evidence from a large randomized trial. But when I realize that I would make different recommendations based on the reasonable values at each end of the CI, I know that I must downgrade the quality of the evidence for such imprecision. Recommendations for HIV vaccine based on this trial, using the GRADE scheme, would certainly be graded as having no better than moderate quality evidence because of this imprecision.
Instead of some arbitrary definition of whether a trial is large enough or precise enough, using the CI in this way allows me to communicate something important about the quality of the evidence as I grade recommendations. I downgrade for imprecision not because a CI crosses a null effect boundary (like 1.0 for a relative risk) but because the CI crosses a clinical boundary where the appropriate recommendation would change from one side of the boundary to the other.
In this way, the CI is far more useful than a p value. I keep in the back of my mind, though, that the CI doesn't really mean what I'm trying to use it to mean -- it's just that I usually don't have anything better.
I'll write more in the future about how GRADE looks at other types of limitations on the quality of evidence from randomized trials.

CONSORT 2010 Explanation and Elaboration: updated guidelines for reporting parallel group randomised trials

2011-09-02T18:36:00.000-07:00

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BMJ

2010; 340:c869 doi: 10.1136/bmj.c869 (Published 23 March 2010)

Cite this as: BMJ 2010; 340:c869

Research Methods & Reporting

CONSORT 2010 Explanation and Elaboration: updated guidelines for reporting parallel group randomised trials

OPEN ACCESS

David Moher, senior scientist1,

Sally Hopewell, senior research fellow2,

Kenneth F Schulz, distinguished scientist and vice president3,

Victor Montori, professor of medicine4,

Peter C Gøtzsche, director5,

P J Devereaux, clinical scholar6,

Diana Elbourne, professor of health care evaluation7,

Matthias Egger, head of department and professor of epidemiology and public health8,

Douglas G Altman, professor2

+Author Affiliations

¹Ottawa Methods Centre, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa Hospital, Ottawa, Ontario, Canada, K1H 8L6

²Centre for Statistics in Medicine, University of Oxford, Wolfson College, Oxford

³Family Health International, Research Triangle Park, NC 27709, USA

⁴UK Knowledge and Encounter Research Unit, Mayo Clinic, Rochester, MN, USA

⁵The Nordic Cochrane Centre, Rigshospitalet, Blegdamsvej 9, Copenhagen, Denmark

⁶McMaster University Health Sciences Centre, Hamilton, Canada

⁷Medical Statistics Unit, London School of Hygiene and Tropical Medicine, London

⁸Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland

Correspondence to: D Moher dmoher@ohri.ca

Accepted 8 February 2010

Abstract

Overwhelming evidence shows the quality of reporting of randomised controlled trials (RCTs) is not optimal. Without transparent reporting, readers cannot judge the reliability and validity of trial findings nor extract information for systematic reviews. Recent methodological analyses indicate that inadequate reporting and design are associated with biased estimates of treatment effects. Such systematic error is seriously damaging to RCTs, which are considered the gold standard for evaluating interventions because of their ability to minimise or avoid bias.

A group of scientists and editors developed the CONSORT (Consolidated Standards of Reporting Trials) statement to improve the quality of reporting of RCTs. It was first published in 1996 and updated in 2001. The statement consists of a checklist and flow diagram that authors can use for reporting an RCT. Many leading medical journals and major international editorial groups have endorsed the CONSORT statement. The statement facilitates critical appraisal and interpretation of RCTs.

During the 2001 CONSORT revision, it became clear that explanation and elaboration of the principles underlying the CONSORT statement would help investigators and others to write or appraise trial reports. A CONSORT explanation and elaboration article was published in 2001 alongside the 2001 version of the CONSORT statement.

After an expert meeting in January 2007, the CONSORT statement has been further revised and is published as the CONSORT 2010 Statement. This update improves the wording and clarity of the previous checklist and incorporates recommendations related to topics that have only recently received recognition, such as selective outcome reporting bias.

This explanatory and elaboration document—intended to enhance the use, understanding, and dissemination of the CONSORT statement—has also been extensively revised. It presents the meaning and rationale for each new and updated checklist item providing examples of good reporting and, where possible, references to relevant empirical studies. Several examples of flow diagrams are included.

The CONSORT 2010 Statement, this revised explanatory and elaboration document, and the associated website (www.consort-statement.org) should be helpful resources to improve reporting of randomised trials.

“The whole of medicine depends on the transparent reporting of clinical trials.”1

Agradecimiento a Karin Kopitowski (Jefa de Servicio de Medicina Familiar, Hospital Italiano, Buenos Aires) por via facebook acercarnos la versión en castellano: https://docs.google.com/viewer?url=http%3A%2F%2Fwww.elsevier.es%2Fsites%2Fdefault%2Ffiles%2Felsevier%2Feop%2FS0025-7753(10)00989-9.pdf

Los paises en desarrollon también tienen derecho a beneficiarse de la MBE

2011-08-14T17:00:00.000-07:00

Los países en vías de desarrollo tienen derecho a beficiarse de las mejores políticas sanitarias basadas en pruebas. Estas existen, están disponbles y es preciso que lleguen a aquellos lugares y poblaciones donde son necesarias. Pueden salvar millones de vidas.

Os recomiendo consultar la web de la Kaiser Family Foundation, más en concreto su sección "Global Health Foundation". En la misma, bajo el epígrafe "Global Health Interventions: a review of the evidence" accedemos a un pequeño sumario de problemas de salud y enfermedades de ámbito mundial y a un compendio de las intervenciones más eficaces parsa combatirlas. Con su grado de evidencia bien establecido.

Se nos explica que "Global Health Interventions: A Review of Evidence es un esfuerzo para proporcionar información pertinente y accesible sobre la eficacia ("lo que funciona") de las intervenciones clave de salud global, incluida la fuerza de la evidencia. Es una herramienta basada en la web que resume los resultados de una serie de intervenciones de prevención y tratamiento diseñado para reducir el riesgo de muerte y enfermedad en los países en vías de desarrollo. La información se presenta por tema de salud y en varios formatos, incluyendo una descripción narrativa, una tabla de resultados clave, y un modelo lógico de enfermedad".

La fuerza de la evidencia se clasifica de 1 a 6, correspondiendo 6 al de mayor nivel.

Iniciativas como esta son fundamentales para poder aplicar políticas eficaces de prevención y tratamiento de enfermedades en aquellos países que más lo necesitan. Se abordan en esta web enfermedades como la tuberculosis, el SIDA, la malaria, el dengue y la diarrea.

Bienvenida sea esta iniciativa y esta forma práctica y visual de resumir y compendiar las mejores evidencias disponibles para luchar contra estas y otras enfermedades de alta incidencia y prevalencia que asolan los países más desfavorecidos de nuestro planeta.

Forest Plot Viewer: a new graphing tool

2011-08-14T16:55:00.000-07:00

http://dianacuesta.wordpress.com/2011/08/12/forest-plot-viewer-a-new-graphing-tool/

Source:

Boyles AL, Harris SF, Rooney AA, Thayer KA. Forest plot viewer: a new graphing tool.

Epidemiology. 2011 Sep;22(5):746-7

En este artículo recomiendan el programa Forest Plot Viewer para realizar gráficos de estimaciones puntuales con su intervalo de confianza que son utlizadas para graficar las estimaciones de los estudiode un meta-análisis y para graficar las estimaciones de diferentes variables o mediciones de un estudio.

Descargar el programa gratis aqui

Meta-analysis and New Knowledge

2011-08-01T13:45:00.000-07:00

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Source: Evidence in medicine

When hierarchies of evidence are listed for the EBM world, meta-analyses of randomized trials generally sit at the pinnacle.

And yet, the actual meta-analyses that you encounter when researching a clinical question can be far less enlightening. Even if we grant a pass to the many systematic reviews at The Cochrane Collaboration that conclude with the a priori obvious fact that no high quality RCTs addressing a question have been performed, and another pass to the reviews that find a single RCT and publish its results as the results of the systematic review, we are still left with the innumerable meta-analyses that seem to provide less of a window on truth than the underlying trials.

Frequently such meta-analyses are either driven by the single large RCT that everyone would have cited anyway or, worse, a number of small, poorly-performed RCTs are combined with a moderate-sized, well-performed RCT and alter the results away from what was likely the best estimate of reality: the results of the well-performed RCT.

Meta-analysts often seem to either be too removed from their subject area and thus lack the expertise to really understand what went clinically right and wrong in the underlying RCTs (or be unwilling to use that knowledge to discriminate among the trials), or be too cozy with a single trial (typically as an author) and thus too willing to ding trials that found conflicting results.

Ultimately, meta-analysis only rarely seems to importantly advance our knowledge of an issue beyond where we would have found ourselves by just reading through the RCTs.

So with that background it is always interesting to me when a meta-analysis comes along that really seems to shed new light on a subject such that we seem to know something that we somehow didn't know when we just had the underlying trials.

An example came along in The Lancet last week.

Despite the enormous number of patients participating in randomized trials of statins, it has been uncertain what effect statins have on the development of diabetes. Some biochemical and animal studies suggested that statins might prevent diabetes. Clinical trials have been conflicting with some showing protection and other showing increased risk. In reviewing the underlying trials, it has been hard to figure out what is going on:

Are some statins protective while others are harmful?
Are hydrophilic statins having different effects than lipophilic statins?
Was the observation of increased diabetes risk in the JUPITER Trial just a random event that became noticeable because of reporting bias (where positive or interesting secondary outcomes are more likely to show up in a paper than negative results).
Are the varying results of the statin trials due to random variation around a single truth, or do the results suggest that the underlying trials differed from each other in some important way (perhaps because of the population studied, the way the statin was administered, or the way diabetes was assesses?

A month ago, anyone simply looking at the collection of trials would have had a hard time giving a coherent answer to the above questions. Now, after a nicely done meta-analysis by Prof. Naveed Sattar et al., there are reasonable answers to all these questions. And thinking about these questions also sheds light on how to read and judge a meta-analysis.

The new analysis found that patients treated with statins had about a 9% higher risk of diabetes than those treated with placebo or other agents. When I started reading the analysis, I had the questions in the list above already in mind and so was prepared to challenge the meta-analysis on several fronts. The authors of the analysis had appropriately anticipated my concerns and, to the extent the data allowed, answered them:

1) Was this really a chance finding driven by JUPITER? Before JUPITER found an increased risk of diabetes, there had been little discussion of statins and diabetes risk. JUPITER's findings could have been due to chance, but the publicity around the result could have triggered the meta-analysis. JUPITER was large enough to sway the results in the meta-analysis and perhaps lead to a self-fulfilling conclusion based in random variation. The meta-analysis, though, did a secondary analysis that excluded JUPITER, and found that the results were essentially the same.

2) Were the varying results in the trials due to random variation or true differences? The meta-analysis found little need to invoke anything more than randomness (as measured by a statistic called the I²⁾. What had seemed to be conflicting results was likely nearly entirely due to random variation around a likely single true effect of slightly increased risk of diabetes.

3) Are some statins protective while others cause diabetes? The finding of little heterogeneity suggests the answer is no, but ultimately this is a hard question to answer definitively because of the more limited data about each individual statin. The meta-analysis found that the confidence intervals of the effects for individual statins overlapped such that it seemed unlikely that there were important differences among the statins, but it's hard to be certain. Additionally, lipophilic and hydrophilic statins showed the same effects on diabetes. And beyond that, the meta-analysis found that one of the main trials that had suggested a protective effect of pravastatin on diabetes had used an unusual definition of diabetes, and the effect was not seen when they substituted a standard definition.

While no new trials were published, as a result of this meta-analysis we have a much better feel for the effect of statins on diabetes than we had a few weeks ago. So, if after hours of trying to answer clinical questions by reading Cochrane you find yourself wondering whether meta-analyses are ever worth the effort that seems to go into them, remember this one and how much we learned about diabetes and statins from a new analysis of existing data.

Informe de Evaluación de Tecnologias Sanitarias OSTEBA

2011-07-31T19:57:00.001-07:00

Informe Evaluacion Tecnologias San It Arias Osteba

GRADE

2011-07-28T16:39:00.000-07:00

Traduccion GRADE BMJ Atencion Primaria

Grading quality of evidence and strength of recommendations in clinical practice guidelines: Part 2 of 3. The GRADE approach to grading quality of evidence about diagnostic tests and strategies

2011-07-28T13:59:00.000-07:00

J. L. Brożek^1,2,

E. A. Akl³,

R. Jaeschke⁴,

D. M. Lang⁵,

P. Bossuyt⁶,

P. Glasziou⁷,

M. Helfand⁸,

E. Ueffing⁹,

P. Alonso-Coello^10,11,

J. Meerpohl^12,13,

B. Phillips¹⁴,

A. R. Horvath¹⁵,

J. Bousquet¹⁶,

G. H. Guyatt^4,17,

H. J. Schünemann^3,17,

for the GRADE Working Group¹

Article first published online: 29 MAY 2009

DOI: 10.1111/j.1398-9995.2009.02083.x

Issue

Allergy

Volume 64, Issue 8, pages 1109–1116, August 2009

Additional Information(Show All)

How to Cite Author Information Publication History

View Full Article (HTML) Get PDF (223K)

Keywords:

clinical practice guidelines;
diagnosis;
evidence based medicine;
grading

The GRADE approach to grading the quality of evidence and strength of recommendations provides a comprehensive and transparent approach for developing clinical recommendations about using diagnostic tests or diagnostic strategies. Although grading the quality of evidence and strength of recommendations about using tests shares the logic of grading recommendations for treatment, it presents unique challenges. Guideline panels and clinicians should be alert to these special challenges when using the evidence about the accuracy of tests as the basis for clinical decisions. In the GRADE system, valid diagnostic accuracy studies can provide high quality evidence of test accuracy. However, such studies often provide only low quality evidence for the development of recommendations about diagnostic testing, as test accuracy is a surrogate for patient-important outcomes at best. Inferring from data on accuracy that using a test improves outcomes that are important to patients requires availability of an effective treatment, improved patients’ wellbeing through prognostic information, or – by excluding an ominous diagnosis – reduction of anxiety and the opportunity for earlier search for an alternative diagnosis for which beneficial treatment can be available. Assessing the directness of evidence supporting the use of a diagnostic test requires judgments about the relationship between test results and patient-important consequences. Well-designed and conducted studies of allergy tests in parallel with efforts to evaluate allergy treatments critically will encourage improved guideline development for allergic diseases.

Does Health Technology Assesment work ?

2011-07-26T22:25:00.001-07:00

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Does Health Technology Assessment Work?

Published by Stephanie Sutton, PharmTech Europe on July 15, 2011

Health Technology Assessment (HTA) processes are supposed to improve access to innovative treatments and medicines. But are they doing their job? Perhaps not: a new report examining HTAs has highlighted several areas for improvement. In particular, the report found little evidence that current HTA processes accelerate access to medicines or result in better rewards for medicines with high therapeutic values.

The report, titled A comparative analysis of the role and impact of Health Technology Assessment, was jointly commissioned by European Federation of Pharmaceutical Industries and Associations (EFPIA), EuropaBio, Medicines Australia and Pharmaceutical Research and Manufacturers of America (PhRMA) to compare how different systems use HTA, the approach they apply, how it works in practice and the consequences for key stakeholders.

“It is generally agreed that HTA has the potential to assist payers in making informed decisions about allocating resources (including expenditure on medicines) in the health system,” explained the report. “However it is also possible that a poorly designed or managed HTA process runs the risk of denying patients appropriate access to medical technologies, inefficiently allocating resources, constraining clinical freedom and sending distorted signals to medical technology providers.”

HTAs can be difficult to understand because their role varies from country to country. HTAs can influence market access, price and/or reimbursement, and different HTAs will assess medicines in different ways; some look at therapeutic value, while others focus on economic factors or regional disparities. The majority of HTAs examined in the report are part of the pricing and reimbursement process, but some, such as the UK’s National Institute for Health and Clinical Excellence, are separate entities entirely. Simple, yes?

If you’re a bit lost you’re not the only one. One of the points identified in the report is that the overall link between HTA and pricing and reimbursement is unclear in many cases. In addition, recommendations from HTA bodies are not always implemented by pricing and reimbursement authorities.

“Recommendations on the same products also vary greatly between systems and countries,” said a statement from EFPIA. “While individual HTA bodies may have different remits and objectives, the variation in how the same products are evaluated suggest inefficiencies and inconsistencies linked with diverging methodologies and data requirements.”

The report adds that many systems can also improve their performance by adopting a holistic approach to assessments. “Looking at the full healthcare system and associated costs for society would be more beneficial in terms of efficient allocation of resources. Even though HTA has the potential to assist patients and health practitioners in making informed decisions, in practice, societal aspects are not well taken into account and patients have a limited role in several HTA systems,” said EFPIA.

So, do we need a radical overhaul of HTAs? We shouldn’t be too hasty. After all, HTAs are fairly new and still developing. The report acknowledges this and recommends re-assessments on an annual or bi-yearly basis to enable the impact of HTAs to be efficiently captured over time. At the moment, the report stresses that there is no clear evidence that the impact of HTAs are being monitored, which makes it difficult to tell whether they improve allocation of resources or offer value for money.

The full report is available at www.efpia.org, if you fancy a light read this weekend. Let me know your thoughts on the report’s findings!

Evidence updates

2011-07-24T23:53:00.000-07:00

11-22-2010

Evidence Based Medicine & HTA

Health Techonology Assessment and Safety Patient

Efectividad de la artroscopia de rodilla

Valoracion de los ensayos clinicos: CONSORT

Integrated management of type 2 diabetes mellitus and depression treatment to improve medication adherence: a randomized controlled trial

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Routine HIV Screening — What Counts in Evidence-Based Policy?

Routine HIV Screening — What Counts in Evidence-Based Policy?

SOURCE INFORMATION

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Source: Evidenceinmedicine

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Los paises en desarrollon también tienen derecho a beneficiarse de la MBE

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Grading quality of evidence and strength of recommendations in clinical practice guidelines: Part 2 of 3. The GRADE approach to grading quality of evidence about diagnostic tests and strategies

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Keywords:

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Does Health Technology Assessment Work?

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