Use of Patient-Reported Outcomes in Randomized, Double-Blind, Placebo-Controlled Clinical Trials

Background: To optimize the use of patient-reported outcomes (PROs) in clinical research, it is first necessary to review the current use of these outcomes in clinical trials to determine under what circumstances they are most useful, and to reveal current limitations. Purpose: To investigate current patterns of use of PROs in clinical trials. Research Design: We conducted a systematic literature review of all double-blind, placebo-controlled, randomized clinical trials using one or more PROs as a study outcome from 2004 to 2006. Data were abstracted and analyzed with descriptive statistics and logistic regression to characterize the use of PROs in clinical trials. Results: The 180 clinical trials that met the study inclusion criteria used 173 unique instruments to measure a total of 466 PROs. Most PRO measurements were obtained using relatively few PRO instruments, with one-third of PRO instruments applied in more than 1 trial. In multivariable analysis, tests of statistical significance were more often reported for PROs used as primary trial outcomes. Statistically significant PRO outcomes (P < 0.05) were more likely among disease-specific PROs compared with general PROs, PROs with a discussion of minimally important difference, and larger trials. Conclusions: PRO instruments may be improved through efforts to provide centralized electronic administration, cross-validation, and standardized interpretation of clinically relevant outcomes. The majority of PROs used in current clinical trials come from relatively few, commonly used disease-specific PRO instruments within major therapeutic areas.