Cost-effectiveness of olanzapine versus haloperidol in the treatment of schizophrenic patients in Spain

Background: Cost-effectiveness of olanzapine in comparison with haloperidol, in Spanish schizophrenic patients, was analysed using a clinical decision model. Methods: The model represents a simulation of the different clinical and therapeutic possibilities that an hypothetical cohort of patients could experience in a 5-years period of treatment. Efficacy was measured as months with partial-complete remission. Most information was obtained from the HGAJ randomised clinical trial. Other information was estimated through literature reviews and the opinion of and expert panel. Results: Average cost-effectiveness for olanzapine was lower (116, 476 pesetas per month with partial-complete remission) that for haloperidol (134, 762 pesetas per month with partial-complete remission). Olanzapine produced more than half year (6.7 months) with partial-complete remission, in comparison with haloperidol, with an incrementar costeffectiveness of 32,516 pesetas per month with partial-complete remission, in comparison with haloperidol. The results were not sensitive to changes in the values of the main variables used in the analysis. Conclusions: According to this analysis, olanzapine presents a good cost-effectiveness relationship in comparison with haloperidol, in Spanish schizophrenic patients. The analysis with be completen when new studies comparing olanzapine with other antipsychotics are available.