Effect of duloxetine on functional outcomes in patients with major depressive disorder

Objective: Patients with major depressive disorder (MDD) often have a reduced ability to function socially, maintain and enjoy relationships and work. The aim of this analysis was to investigate the efficacy of duloxetine vs. placebo on improvement in functioning after 8 weeks of treatment.

Methods: This was a pooled analysis of data from two separate 9-month studies conducted under the same protocol in patients with MDD (DSM-IV-TR) to examine the efficacy of duloxetine 60 mg/day (n = 518) vs. placebo (n = 258) on impairment in functioning. Pooling the data from these studies was specified a priori in the protocol to allow for increased power to detect differences between duloxetine and placebo on secondary and exploratory objectives. The measures included in this analysis were: the Hamilton Depression Rating Scale (HAMD) Item 7 (Work / Activities), the Sheehan Disability Scale (SDS), the Social Adaptation Self-evaluation Scale (SASS) to assess social behavior, the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (CPFQ) and the Profile of Mood States -brief form (BPOMS) subscales Vigor / Activity (VA) and Fatigue / Inertia (FI) used as surrogate measures of function. Mean changes from baseline were analyzed by using a mixed-effects model repeated measures approach (MMRM). An analysis of covariance (ANCOVA) using a last observation carried forward (LOCF) approach was conducted as a sensitivity analysis. The endpoint for this analysis was at week 8.

Results: At baseline, patients had moderately severe levels of SDS global functional impairment scores (18.3±6.9). At the endpoint, there was significant improvement from baseline (MMRM) with duloxetine treatment on the HAMD Work / Activities (p<.001), Sheehan Disability Scale global (p=.002), SASS total (p<.001), Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (p<.001) and BPOMS Vigor / Activity (p=.012) and Fatigue / Inertia (p=.006) subscales. At the endpoint (LOCF imputation), duloxetine-treated versus placebo-treated patients had significantly greater improvement from baseline on the HAMD Work / Activities, SDS global, SASS total, CPFQ total and Profile of Mood States -brief form subscales VA and FI.

Conclusion: These results suggest that treatment with duloxetine may improve functional impairment in patients with major depressive disorder.