OBJECTIVE: To estimate and compare the efficacy, treatment-emergent adverse events, costs and outcomes of olanzapine and ziprasidone for treatment of schizophrenia.
METHODS: A decision-analytic model was used to determine outcomes for patients treated over a 1-year period. Model parameters were based on clinical trial data and published medical literature. Data from different trials were compared only when patient populations were similar. Comparative studies were available for weight gain and cardiovascular events. For essential parameters with no relevant study results, assumptions were made that the medications would be similar.
RESULTS: Compared to patients treated with ziprasidone, data seem to suggest that olanzapine patients had a higher response rate, a higher incidence of weight gain, and a lower incidence of QTc prolongation. Total medical cost was higher for ziprasidone patients when the medication cost of ziprasidone was assumed to be more than half the price than that of olanzapine. The olanzapine group's costs were more sensitive to changes in drug costs, whereas the ziprasidone group's costs were more sensitive to the response rate of the medication used for those patients not responsive to ziprasidone.
CONCLUSIONS: Compared to ziprasidone patients, olanzapine patients may have a higher response rate, a higher incidence of weight gain, and a lower incidence of QTc prolongation, with lower total costs as long as ziprasidone is more than half the price of olanzapine.
