Divalproex Sodium Versus Olanzapine in the Treatment of Acute Mania in Bipolar Disorder: Health-Related Quality of Life and Medical Cost Outcomes

Background: Divalproex sodium is a mood stabilizer used in the United States for the treatment of acute mania associated with bipolar disorder. Recently, olanzapine, an atypical antipsychotic, was approved for the treatment of acute mania. This study compares the clinical, health-related quality of life (HRQL), and economic outcomes of divalproex and olanzapine in the treatment of acute mania associated with bipolar disorder.

Method: This 12-week, double-blind, double-dummy, randomized clinical trial included 120 subjects with DSM-IV bipolar disorder type I hospitalized for an acute manic episode recruited from 21 U.S. clinical centers. Subjects were randomly assigned to treatment with either divalproex or olanzapine and were followed in hospital for up to 21 days. If after 21 days clinical improvements (based on the Mania Rating Scale [MRS]) were not observed, subjects were discontinued. Subjects showing clinical improvement were treated for up to 12 weeks. HRQL was assessed using the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) after hospital discharge (baseline) and at 6 and 12 weeks. Medical resource use and costs were collected over the 12-week study.

Results: A total of 120 subjects (N = 63 divalproex, N = 57 olanzapine) were randomized, and 78 (65%) were followed beyond 21 days. No statistically significant differences between the treatment groups for baseline-to-endpoint MRS or Q-LES-Q scores were observed. Total 12-week outpatient medical costs were significantly lower for the divalproex-treated group ($541) compared with the olanzapine-treated group ($1080) (p = .004). There was no significant difference in total medical costs between the 2 groups (divalproex = $13,703; olanzapine = $15,180; p = .88).

Conclusion: Divalproex is associated with lower 12-week outpatient costs compared with olanzapine. Divalproex and olanzapine have similar short-term effects on clinical or HRQL outcomes in bipolar disorder subjects.