PMH15: A RETROSPECTIVE ECONOMIC EVALUATION OF OLANZAPINE VERSUS RISPERIDONE IN THE TREATMENT OF SCHIZOPHRENIA

Abstract

OBJECTIVES: The purpose of this study was to assess the one-year direct schizophrenia-related treatment costs, mental health care costs and total health care costs for patients diagnosed with schizophrenia and initiating therapy with either olanzapine or risperidone. METHODS: A retrospective analysis of the integrated medical and pharmacy claims of a large, geographically diverse, commercially insured population was conducted. A previously validated algorithm to identify schizophrenics was used for patient selection. The confirmed schizophrenia patients who began treatment with either olanzapine or risperidone were included. Treatment course and associated schizophrenia-related, mental health care and total health care costs during the subsequent 12-month period were examined using univariate and multivariate methods. RESULTS: Nine hundred eighty-five (985) patients initiated on risperidone and 348 initiated on olanzapine met inclusion criteria. The mean dose was 4.02 and 10.49 for risperidone and olanzapine patients, respectively. Patients taking olanzapine versus risperidone stayed on therapy longer during the 12-month observation period (217 days versus 181 days, p < 0.0001). Although pharmaceutical costs were significantly higher for olanzapine patients, their medical costs were significantly lower than those on risperidone. After adjusting for differences in patient demographics, disease severity and comorbidities, olanzapine patients had significantly lower mental health care costs including drug costs ($1,827 less, p < 0.05) and lower total health care costs ($1,834 less, p < 0.05). The schizophrenia-related costs (including drug costs) were not statistically significantly different, though numerically the risperidone patients incurred $740 more per patient than patients on olanzapine (p = 0.26). CONCLUSIONS: The findings in this study suggest that the initial selection of atypical antipsychotic for the treatment of schizophrenia matters, as olanzapine offset its acquisition cost by reducing medical costs and demonstrated significant mental and total health care cost savings over risperidone.