Moderation of antidepressant and placebo outcomes by baseline severity in late-life depression: A systematic review and meta-analysis

Background: Baseline severity is a crucial moderator of trial outcomes in adult depression, with the advantage of antidepressants over placebo increasing as severity increases. However, this relationship has not been examined in late life depression. Methods: PubMed, Embase, Web of Science, PsycINFO, and Cochrane were searched for studies published through September 2014. Randomized, acute phase, and double-blind studies comparing an antidepressant group with a placebo group in depressed elderly patients were included. Results: Nineteen studies met all inclusion criteria. Within group effect sizes revealed significant improvement in antidepressant groups (g=1.35, p < .000), as well as in placebo groups (g=.96, p < .000). Change in depressive symptoms assessed by Hamilton Depression Rating Scale (HDRS) was moderated by baseline severity in antidepressant groups (Z=2.67, p = .008) and placebo groups (Z=4.46, p < .000). However, this would be expected as a result of regression toward the mean, and mean differences between groups did not increase (r=.19, p=.469) as a function of baseline severity. Limitations: Limited to published data and information was only analyzed at the level of treatment groups. Conclusion: Baseline severity was not associated with an antidepressant-placebo difference and placebo responses are large in the treatment of depressed elderly people. We propose a stepwise approach, i.e., to initially offer elderly depressed patients psychosocial interventions and only consider antidepressants if patients do not respond. (C) 2015 Elsevier B.V. All rights reserved