Effect Size Of Open-Label Versus Double-Blind Administration Of Tiotropium ln Trials lnvestigating Health-Related Quality Of Life ln COPD

Introduction: Effects of interventions on patient-reported outcomes may be subjective and modulated by patients' expectations regarding treatment efficacy. The gold standard for minimizing such bias is the double-blind [DB] randomized controlled trial. We analyzed the effects of tiotropium (T) on health-related quality of life [HRQOL] in COPD in placebo [PL] -controlled trials and assessed whether the trial design (DB vs open-label [OL]) is a relevant modifier of the effects of T. Methods: Trials of at least 6 months' duration exploring the effect of T vs PL on HRQOL in COPD (using the St George's Respiratory Qu…