Background: Rapid response to antidepressant therapy is desirable and may be particularly critical in elderly patients with major depressive disorder (MDD).
Methods: Findings are based on post-hoc analyses from a double-blind trial of elderly patients with MDD ≥ 65 years, randomly assigned 2:1 to duloxetine 60 mg QD (N = 207) or placebo (N = 104) for 8 weeks. Depression and pain measures included the Geriatric Depression Scale (GDS), 17-item Hamilton Depression Scale (HAMD17), CGI-Severity, and Visual Analog Scale (VAS) for overall pain. The time to response and remission for duloxetine compared with placebo was evaluated using Cox proportional hazards (PH) modeling, Kaplan-Meier estimation, and categorical repeated measures analysis.
Results: Significant improvements of estimated HAMD17 response and remission rates for duloxetine started at week 2 (P = 0.022 and P = 0.033, respectively). Time to HAMD17 response and remission were significantly shorter for duloxetine versus placebo (P < 0.001 and P = 0.004, respectively). Placebo-referenced duloxetine hazard ratios (HR) for HAMD17 response and remission were 2.03 (P = 0.002) and 2.01 (P = 0.006), respectively. Results for GDS-based response (HR = 1.54, P = 0.023) and remission (HR = 1.54, P = 0.104) rates were consistent with the HAMD17 findings. Patients ≥75 years (n = 93) responded with similar rapidity to duloxetine compared with those <75 years (n = 199, P > 0.10 for all PH treatment-by-age interactions). The placebo-referenced duloxetine HR for time to 50% reduction in overall pain was 1.75 (P = 0.024) for patients with moderate to severe pain.
Conclusion: Duloxetine demonstrated a faster time to antidepressant response and improvement in self-reported pain as compared with placebo.
Clinical trial registry number for this study: NCT00062673, at www.clinicaltrials.gov.