Clinical and economic outcomes of olanzapine compared with haloperidol for schizophrenia. Results from a randomised clinical trial

Abstract

Objective: The purpose of this study was to compare, from the payor perspective, the clinical and economic outcomes of olanzapine to those of haloperidol for the treatment of schizophrenia.

Design and setting: Clinical, quality-of-life and resource utilisation data were prospectively collected for US-residing patients with schizophrenia who were participating in a multicentre, randomised, double-blind clinical trial comparing olanzapine and haloperidol. Direct medical costs were estimated by assigning standardised prices (1995 values) to the resource utilisation data.

Patients and participants: 817 patients with schizophrenia who had a baseline Brief Psychiatric Rating Scale score (BPRS) > or = 18 (items scored 0 to 6) and/or were no longer tolerating current antipsychotic therapy.

Interventions: Olanzapine 5 to 20 mg/day (n = 551) or haloperidol 5 to 20 mg/day (n = 266) for 6 weeks. Patients showing a predefined level of clinical response entered a 46-week maintenance phase.

Main outcome measures and results: After acute treatment, BPRS-based clinical improvements were seen in 38 and 27% of olanzapine and haloperidol patients, respectively (p = 0.002). Clinically important improvements on the Quality of Life Scale were achieved during acute treatment in 33% of olanzapine recipients and 25% of haloperidol recipients (p = 0.094). Olanzapine treatment in the acute phase led to significantly lower inpatient ($US5125 vs $US5795, p = 0.038) and outpatient ($US663 vs $US692, p = 0.001) costs, resulting in a significant overall reduction in mean total medical costs of $US388 (p = 0.033). This significant reduction in total costs was found despite olanzapine mean medication costs being significantly greater than haloperidol medication costs ($US326 vs $US15, p < 0.001). No significant differences in clinical improvement were observed in the maintenance phase. Maintenance phase olanzapine mean total medical costs were $US636 lower than haloperidol total costs (p = 0.128). Although olanzapine medication costs were significantly higher than haloperidol medication costs ($US3461 vs $US95, p < 0.001), this difference was offset by significantly lower inpatient ($US8322 vs $US10,662, p = 0.044) and outpatient ($US3810 vs $US5473, p = 0.038) costs.

Conclusions: In this study, olanzapine treatment was more effective than haloperidol in producing clinical response in the acute phase. In addition, olanzapine treatment led to reductions in inpatient and outpatient costs that more than offset olanzapine's higher medication costs relative to haloperidol.