Health-related quality of life in patients with depression treated with duloxetine or a selective serotonin reuptake inhibitor in a naturalistic outpatient setting

PURPOSE To assess the levels of quality of life (QoL) in major depressive disorder (MDD) patients treated with either duloxetine or a selective serotonin reuptake inhibitor (SSRI) as monotherapy for up to 6 months in a naturalistic clinical setting mostly in the Middle East, East Asia, and Mexico. PATIENTS AND METHODS Data for this post hoc analysis were taken from a 6-month prospective observational study involving 1,549 MDD patients without sexual dysfunction. QoL was measured using the EQ-5D instrument. Depression severity was measured using the Clinical Global Impression of Severity and the 16-item Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR16), while pain severity was measured using the pain items of the Somatic Symptom Inventory. Regression analyses were performed to compare the levels of QoL between duloxetine-treated (n=556) and SSRI-treated (n=776) patients, adjusting for baseline patient characteristics. RESULTS These MDD patients, on average, had moderately impaired QoL at baseline, and the level of QoL impairment was similar between the duloxetine and SSRI groups (EQ-5D score of 0.46 [SD =0.32] in the former and 0.47 [SD =0.33] in the latter, P=0.066). Both descriptive and regression analyses confirmed QoL improvements in both groups during follow-up, but duloxetine-treated patients achieved higher QoL. At 24 weeks, the estimated mean EQ-5D score was 0.90 in the duloxetine cohort, which was statistically significantly higher than that of 0.83 in the SSRI cohort (P<0.001). Notably, pain severity at baseline was also statistically significantly associated with poorer QoL during follow-up (P<0.001). In addition, this association was observed in the subgroup of SSRI-treated patients (P<0.001), but not in that of duloxetine-treated patients (P=0.479). CONCLUSION Depressed patients treated with duloxetine achieved higher QoL, compared to those treated with SSRIs, possibly in part due to its moderating effect on the link between pain and poorer QoL.