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Detener temprano los ensayos aleatorizados para obtener beneficios y estimar los efectos del tratamiento: revisión

Dirk Bassler¹, Matthias Briel, Victor M Montori

¹Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.

|March 25, 2010

Resumen

Los ensayos controlados aleatorios (ECA) se detuvieron temprano para obtener beneficios sobreestiman los efectos del tratamiento. Este sesgo persiste independientemente de las reglas de parada y es más pronunciado en estudios más pequeños con menos eventos.

Área de la Ciencia:

Metodología de ensayos clínicos Metodología de ensayos clínicos.
La bioestadística es la bioestadística.
La medicina basada en la evidencia.

Sus antecedentes:

La teoría y la simulación sugieren que la interrupción temprana de los ensayos controlados aleatorios (ECA) para obtener beneficios conduce a efectos sobreestimados del tratamiento.
Esta sobreestimación afecta específicamente el resultado que desencadenó la cesación anticipada.

Objetivo del estudio:

Para comparar los efectos del tratamiento en ECA truncados con los de ECA no truncados incluidos en los metanálisis.
Identificar los factores que contribuyen a la sobreestimación de los efectos del tratamiento en ECA truncados.

Principales métodos:

Búsqueda sistemática en varias bases de datos (MEDLINE, EMBASE, etc.) para obtener más información. para ECA truncados y revisiones sistemáticas relevantes.
Revisión independiente y a ciegas por expertos para seleccionar ECA elegibles no truncados que coincidan con los truncados.
Extracción de datos independientes por revisores expertos en metodología.

Principales resultados:

El análisis incluyó 91 ECA truncados y 424 ECA no truncados que coincidían en 63 preguntas de investigación.
Los ECA truncados mostraron una relación agrupada de riesgos relativos de 0,71 en comparación con los ECA no truncados.
La sobreestimación fue independiente de las reglas estadísticas de detención y la calidad del estudio; fue mayor en estudios con <500 eventos.

Conclusiones:

Los ECA truncados se asocian con tamaños de efecto más grandes que los ECA que no se detuvieron temprano.
La diferencia observada en el tamaño del efecto no se ve influenciada por las reglas de parada estadística o la calidad del estudio.
La sobreestimación de los efectos del tratamiento en ECA truncados es más significativa en estudios más pequeños.

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