Economic outcomes associated with olanzapine versus risperidone in the treatment of uncontrolled schizophrenia

This study, based upon a database analysis, compares a one-year drug treatment course (duration of therapy, concomitant use of typical antipsychotics, anxiolytics/antidepressants or anti-Parkinsonians) and direct health care costs of uncontrolled schizophrenia patients initiated on olanzapine versus risperidone.

The integrated medical and pharmacy claims of a large, geographically diverse, commercially insured population of 1.6 million employees, retirees and dependents were used to conduct this analysis. Patients who initiated outpatient treatment with either olanzapine or risperidone (no prescription for olanzapine or risperidone during a 1-year period prior to the initiation) and with uncontrolled schizophrenia were included. Drug treatment course and associated health care costs (calculated based on charges) during the subsequent 12-month period were examined using univariate and multivariate methods.

431 patients initiated on risperidone and 142 initiated on olanzapine met the inclusion criteria. The mean dose was 4.34 and 11.00 mg/day for risperidone and olanzapine, respectively. Olanzapine was associated with more favorable drug treatment course than risperidone. Although pharmaceutical costs were significantly higher, medical costs were significantly lower for patients on olanzapine compared to those on risperidone. Univariate and multivariate analyses (controlling for potential confounding factors including demographic and clinical characteristics) consistently demonstrated that olanzapine patients had significantly lower schizophrenia related costs (2839 US dollars less, p < 0.011), lower mental health care costs (3744 US dollars less, p < 0.004) and lower total health care costs (4674 US dollars less, p < 0.001) than those patients initiated on risperidone.

The findings revealed significant differences between olanzapine and risperidone in the treatment of uncontrolled schizophrenia patients in clinical practice. Olanzapine patients experienced a favorable drug treatment course and incurred lower overall costs. The lower costs were hospital-treatment driven. Further studies are needed to examine if these results hold for different patient populations.