A comparison of olanzapine and risperidone on the risk of psychiatric hospitalization in the naturalistic treatment of patients with schizophrenia

BACKGROUND: Decreasing hospital admissions is important for improving outcomes for people with schizophrenia and for reducing cost of hospitalization, the largest expenditure in treating this persistent and severe mental illness. This prospective observational study compared olanzapine and risperidone on one-year psychiatric hospitalization rate, duration, and time to hospitalization in the treatment of patients with schizophrenia in usual care. METHODS: We examined data of patients newly initiated on olanzapine (N = 159) or risperidone (N = 112) who continued on the index antipsychotic for at least one year following initiation. Patients were participants in a 3-year prospective, observational study of schizophrenia patients in the US. Outcome measures were percent of hospitalized patients, total days hospitalized per patient, and time to first hospitalization during the one-year post initiation. Analyses employed a generalized linear model with adjustments for demographic and clinical variables. A two-part model was used to confirm the findings. Time to hospitalization was measured by the Kaplan-Meier survival formula. RESULTS: Compared to risperidone, olanzapine-treated patients had significantly lower hospitalization rates, (24.1% vs. 14.4%, respectively, p = 0.040) and significantly fewer hospitalization days (14.5 days vs. 9.9 days, respectively, p = 0.035). The mean difference of 4.6 days translated to $2,502 in annual psychiatric hospitalization cost savings per olanzapine-treated patient, on average. CONCLUSIONS: Consistent with prior clinical trial research, treatment-adherent schizophrenia patients who were treated in usual care with olanzapine had a lower risk of psychiatric hospitalization than risperidone-treated patients. Lower hospitalization costs appear to more than offset the higher medication acquisition cost of olanzapine.