Meta-analysis of relapse prevention antidepressant trials in depressive disorders.

OBJECTIVE Continuation therapy with antidepressants is recommended for depressed patients who have responded to initial treatment. We quantified its efficacy in preventing relapse of depression in a meta-analysis of 54 double-blind placebo-controlled relapse prevention studies (patient n = 9268). METHOD Relapse prevention studies in primary depression and depression subtypes were identified in a systematic literature search. The primary efficacy comparison was relapse rates between active and placebo arms calculated as odds ratios (ORs) using Review Manager version 5.0. Effects of patient age, drug class, diagnostic system and duration of therapy on ORs was examined, along with ORs calculated using different statistical methods. RESULTS Continuation antidepressants produced robust reduction in relapse (OR = 0.35; 95%CI 0.32-0.39). Pooled ORs were not affected by patient age, drug class, depression subtype or treatment duration, and were similar when calculated by different statistical methods. Patients with primary depression diagnosed by earlier diagnostic systems had slightly lower ORs than those diagnosed using DSM criteria. CONCLUSIONS This meta-analysis emphasizes the importance of continuation treatment following acute response in depressive disorders. The robust findings of relapse prevention designs contrast with acute antidepressant efficacy studies, and may be due to enrichment of the patient population.