Olanzapine versus Risperidone: A Prospective Comparison of Clinical and Economic Outcomes in Schizophrenia

Abstract

Objective: To compare the clinical and economic outcomes associated with olanzapine and risperidone treatment for schizophrenia. Design and setting: An international, multicentre, double-blind, prospective study. To facilitate economic comparisons, our sample was restricted to patients enrolled in US sites. 150 patients with a Diagnostic and Statistical Manual of mental disorders, 4th edition (DSM-IV) diagnosis of schizophrenia, schizoaffective disorder or schizophreniform disorder were randomised to therapy with either olanzapine 10 to 20 mg/day (n = 75) or risperidone 4 to 12 mg/day (n = 75) for a maximum of 28 weeks. In addition to tolerability and efficacy assessments, use of health services was assessed at baseline and prospectively, at 8-week intervals and at study completion. Clinically important response, defined as a 40% improvement in the Positive and Negative Syndrome Scale total score, maintenance of response and rates of treatment-emergent extrapyramidal symptoms were compared between groups. Direct medical costs were estimated by assigning standardised prices to resource units. Median total, inpatient/outpatient service and medication acquisition costs were compared between treatment groups. Main outcome measures and results: The mean modal dosages for the olanzapine and risperidone treatment groups were 17.7 +- 3.4 mg/day and 7.9 +- 3.2 mg/day, respectively. Olanzapine-treated patients were more likely to maintain response compared with risperidone-treated patients (p = 0.048). In addition, a smaller proportion of olanzapine-treated patients required anticholinergic therapy compared with risperidone-treated patients (25.3 vs 45.3%; p = 0.016). Total per patient medical costs over the study interval were $US2843 (1997 values) [36$US2513 vs $US1581; pAntipsychotics, Cost analysis, Olanzapine, Pharmacoeconomics, Risperidone, Schizophrenia