El rey a examen. Lectura crítica de estudios sobre tratamiento.

The randomized clinical trial is an interventional and analytical design, with antegrade direction and concurrent temporality, with sampling of a closed cohort and control of the exposure. It is the most appropriate design to assess the effectiveness of a treatment and the only that provides higher quality evidence to demonstrate the causal relationship between the intervention and the observed results. We review its structure, its association and impact measures and some variations of its basic design.El ensayo clínico aleatorizado es el diseño ideal para resolver las preguntas sobre tratamiento. La lectura crítica de estos trabajos valorará su validez metodológica, la importancia de los resultados y su aplicabilidad a nuestra práctica clínica. Para ello, habrá que examinar los aspectos fundamentales del ensayo, tales como aleatorización, enmascaramiento y seguimiento