Factors predicting relapse in elderly patients with major depressive disorder treated with escitalopram in an outpatient setting

Objective: We investigated which factors can best predict relapse in older patients with major depressive disorder (MDD) who have achieved remission with escitalopram. Methods: A total of 405 patients who were 65 years or older with a primary diagnosis of MDD received 12 week, open-label escitalopram 10 or 20 mg/day. Patients in remission (MADRS <= 12) at Week 12 were randomized to 24 weeks of double-blind treatment with either placebo or escitalopram (fixed dose from Week 6). Results: After randomization of 312 patients in remission, patients whose dose had been increased to 20 mg escitalopram after 2 weeks of open-label treatment had a high escitalopram relapse rate (16.7%) and a placebo relapse rate of 32.5% with a hazard ratio (HR) of 2.2, whereas patients titrated to 20 mg escitalopram at Weeks 4 or 6 had a high placebo relapse rate (41.2%) and an escitalopram relapse rate of 5.7% with a HR-8.9. A high placebo relapse rate was also observed for patients with a baseline MADRS below median, while low escitalopram relapse rates were characteristic of patients who had achieved remission by Week 6 or 8 (HR=8.9), had a current depressive episode length below median, baseline MADRS below median (HR=11.8), or received 10 mg for 12 weeks (HR=6.3). A key limitation of the study was that some analyses were post-hoc and that none of the comparisons between complementary subgroups had nominal p-values <0.05. Conclusions: In this post-hoc analysis of elderly patients with MDD, several factors, including female gender, early remission, low baseline MADRS score, major depressive episode (MDE) duration, and escitalopram dosage, significantly affected the relapse rate after randomization to escitalopram or placebo.