Clinic Visits in Late-Life Depression Trials: Effects on Signal Detection and Therapeutic Outcome

Objective This meta-analysis investigated how the supportive care provided in antidepressant clinical trials for late-life depression influences response and drop-out rates. Methods Medline, PsycINFO, and PubMed were searched to identify trials contrasting antidepressants with placebo or active comparator in outpatients aged at least 60 years with major depressive disorder. Hierarchical linear modeling was used to determine whether treatment assignment (medication versus placebo), study type (placebo-controlled or comparator), study duration, and the number of study visits affected response and attrition rates. Results In the response rate analysis, a significant interaction was found between study visits and treatment assignment (odds ratio [OR]: 0.89, t = −2.186, df = 36, p = 0.035), such that each additional visit over the grand mean for the sample increased average placebo response by 2.5% while not significantly affecting medication response. Controlling for other variables, the effect of this interaction was to dramatically decrease average medication versus placebo differences in trials having greater numbers of study visits. Neither the number of study visits (OR: 0.96, t = −0.468, df = 14, p = 0.646) nor the treatment × visits interaction (OR: 1.03, t = 0.463, df = 35, p = 0.645) influenced drop-out rates. Conclusion Increased supportive care in the form of clinic visits leads to greater placebo but not antidepressant medication response in clinical trials for late-life depression. Less frequent visit schedules may increase average medication–placebo differences in randomized controlled trials without appreciably increasing drop-out rates.