Exclusion rates in randomized controlled trials of treatments for physical conditions: a systematic review.

Background: The generalisability of randomized controlled trials (RCTs) can be uncertain because the impact of exclusion criteria is rarely quantified. The aim of this study was to systematically review studies examining the percentage of clinical populations with a physical health condition who would be excluded by RCTs of treatments for that condition.

Methods: Medline and Embase were searched from inception to Feb 11th 2018.