Placebo run-in periods in anticholinergic trials are not associated with treatment effect size or risk of attrition: an empirical evaluation.

Abstract

OBJECTIVES: We aimed to explore the impact of run-in periods on the magnitude of treatment effect and the risk of attrition in a sample of randomized trials. STUDY DESIGN AND SETTING: We identified randomized trials from a published systematic review examining the effects of anticholinergics for the treatment of overactive bladders. We fitted meta-analytic mixed-effects models to assess whether the type of run-in (placebo run-in vs. no run-in) was associated with the magnitude of the effect estimates for the following outcomes: the number of voids per day, number of leakages per day, presence of dry mouth, cure/improvement, patient withdrawal from the trial, compliance with the trial protoco..