Service utilization and costs of olanzapine versus divalproex treatment for acute mania: results from a randomized, 47-week clinical trial.

This study examined direct treatment costs based on medication and service use data collected in a 47-week multi-center, double-blind, randomized clinical trial of olanzapine versus divalproex for patients with bipolar disorder and and experiencing acute mania. Patients who completed the 3-week acute phase and entered into the 44-week maintenance phase (n = 147) of the trial were included. Service use data were collected at weeks 3, 7, 15, 23, 31, 39 and 47 of the maintenance phase. Analyses were conducted to address potential biases from discontinuation patterns and use of this patient sub-sample. Overall, per patient yearly costs were similar for olanzapine- and divalproex-treated patients ($14 967 vs. $15 801). Psychiatric-related costs accounted for 95.4% and 93.6% of the total costs for olanzapine- and divalproextreated patients, respectively. Study medication costs were significantly higher for olanzapine than for divalproex ($4662 vs. $1755, p < 0.01). However, this was offset by the combined effects of numerically lower costs for several other services with olanzapine treatment. Some of the savings associated with olanzapine treatment compared with divalproex treatment resulted from differences in costs associated with emergency room services ($432 vs. $1346, p < 0.05). Overall per-patient treatment costs were similar for olanzapine and divalproex. Recognizing challenges in analyzing and generalizing cost outcomes from a clinical trial setting, results provide some much-needed comparative economic information regarding these two medication options for treating mania in bipolar disorder.