Efficacy of duloxetine on painful physical symptoms in major depressive disorder for patients with clinically significant painful physical symptoms at baseline: a meta-analysis of 11 double-blind, placebo-controlled clinical trials.

Objective: To review efficacy of duloxetine for physical symptoms and depressive illness in patients with at least mild to moderate major depressive disorder (MDD; DSM-IV) and clinically significant painful physical symptoms at baseline.

Data Sources: Global database of duloxetine clinical trials (Eli Lilly and Company).

Study Selection: All 11 acute, double-blind, placebo-controlled studies of duloxetine (7 with duloxetine 60-mg doses and 4 with non-60-mg doses) in the database that used a scale to measure painful physical symptoms and were completed before March 17, 2011.

Data Extraction: For each study, patients with clinically significant pain levels at baseline (Visual Analog Scale overall pain rating ≥ 30, Numerical Rating Scale score ≥ 3, or Brief Pain Inventory 24-hour average pain rating ≥ 3) were selected in order to determine the effect sizes of duloxetine (compared with placebo for each trial) on the pain and depression measures. Overall effect sizes for both painful physical symptoms and MDD were obtained from the mean of individual-trial effect sizes, and each effect size was weighted relative to the number of patients within each study.

Data Synthesis: The overall mean effect sizes were as follows: painful physical symptoms-60-mg trials, 0.29 (95% CI, 0.06 to 0.52); non-60-mg trials, 0.13 (95% CI, -0.19 to 0.45); MDD-60-mg trials, 0.29 (95% CI, 0.18 to 0.40); non-60-mg trials, 0.16 (95% CI, 0.00 to 0.32). Across the 11 studies, the weighted effect size for painful physical symptoms was 0.26 (95% CI, 0.00 to 0.51) and for MDD, 0.25 (95% CI, 0.16 to 0.34).

Conclusions: According to this meta-analysis, duloxetine 60 mg once daily is as effective in improving painful physical symptoms as it is for depression in patients with MDD and clinically significant painful physical symptoms. The results of this meta-analysis indicate that duloxetine has small effect sizes in reducing painful physical symptoms and depressive symptoms in patients with MDD and clinically significant pain levels at baseline. Thus, the results of the study permit one to conclude that duloxetine has a clinically significant impact on painful physical symptoms and in reducing the severity of depressive symptoms. However, the results do not address its efficacy compared to other alternatives, as in all studies the comparator was placebo.