Effects of olanzapine alone and olanzapine/fluoxetine combination on health-related quality of life in patients with bipolar depression: secondary analyses of a double-blind, placebo-controlled, randomized clinical trial.

BACKGROUND

Improving patients' health-related quality of life (HRQOL) could be a treatment goal for bipolar depression.

OBJECTIVES

The objectives of these secondary analyses of a previous report were to determine the benefits of olanzapine alone and olanzapine-fluoxetine combination (OFC) for improving HRQOL in patients with bipolar depression using both a generic and a depression-specific HRQOL instrument, and to examine the association between the 2 HRQOL instruments and the construct validity of the depression-specific HRQOL instrument.

METHODS

This was a double-blind, placebo-controlled, 83-site, international, randomized trial. Adults with bipolar I disorder, most recent episode depressed (according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), were randomly assigned to receive olanzapine (6-20 mg/d), OFC (6/25, 12/25, or 12/50 mg/d), or placebo for 8 weeks. HRQOL improvement was calculated as last-observation-carried-forward changes in dimension and component summary scores on Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and total score on the Quality of Life in Depression Scale (QLDS).

RESULTS

Patients were assigned to receive olanzapine (n = 370), [corrected] OFC (n = 86), or placebo (n = 377) [corrected] for 8 weeks. Of 833 enrolled patients, 454 discontinued (olanzapine, 191/370 [51.6%] [corrected]OFC, 31/86 [36.0%]; and placebo, 232/377 [61.6%]) [corrected] Compared with placebo, olanzapine-treated patients exhibited greater improvements on SF-36 mental component summary (MCS) score ( P=0.002) and 3 of 8 SF-36 dimension scores (mental health [P=0.015], role-emotional [P=0.046], and social functioning [P=0.006). OFC-treated patients exhibited greater improvements on MCS score ( P<0.001) vs both placebo and olanzapine), 5 SF-36 dimension scores (general health perception (P<0.001) vs placebo; (P<0.001) vs olanzapinel, mental health [ P=0.001] vs both placebo and olanzapine], role-emotional [ P<0.001] vs placebo; [P=0.007] vs olanzapine], social functioning [ P=0.001] vs placebo; [P=0.032] vs olanzapine], and vitality [P=0.002] vs placebo; [P=0.011] vs olanzapine]), and QLDS total score ( P<0.001] vs both placebo and olanzapine). Changes in SF-36 scores of mental health, social functioning, role-emotional, and vitality were highly correlated to changes in the QLDS total score (all p < -0.5).

CONCLUSIONS

Based on these analyses, patients with bipolar depression receiving olanzapine or OFC for 8 weeks had greater improvement in HRQOL than those receiving placebo. OFC treatment was associated with greater improvement in HRQOL than olanzapine alone. The correlation results support the construct validity of the QLDS.