Cost-effectiveness and price of aripiprazole for schizophrenia in the brazilian public health system

Abstract

Background: Schizophrenia is a chronic debilitating condition characterized by disorders in thought, affect and behavior. Considering the low effectiveness of antipsychotic drugs for schizophrenia and the potentially high cost of an inadequate choice, a systematic cost-effectiveness evaluation of the list of subsidized antipsychotic drugs is necessary in order to allow an adequate choice of pharmacotherapy for the patient and the financial reality of the Brazilian public health system (SUS).

Objective: The aims of this study are to conduct a cost-effectiveness analysis of the subsidized antipsychotic drugs for the first-line treatment of schizophrenia in Brazil and aripiprazole, and to discuss a reasonable incorporation price for aripiprazole.

Methods: A three-year Markov model with quarterly cycles was developed in TreeAge Pro® 2009 to assess the cost-effectiveness of six listed oral antipsychotic drugs for the first-line treatment of schizophrenia in the Brazilian public health system (haloperidol, chlorpromazine, risperidone , quetiapine, ziprasidone, and olanzapine) and oral aripiprazole. Outcomes were measured in quality-adjusted life years (QALYs). Reasonable prices for aripiprazole were calculated based on the placement of the drug in the efficiency frontier and the cost-effectiveness ratio of the most efficient comparator.

Results: Olanzapine was considered cost-effective adopting any threshold value. If me-too drugs are required to be at least as efficient as the comparators, olanzapine would still be cost-effective under 0.031 USD/mg. Aripiprazole was absolutely dominated by risperidone. The sensitivity analysis showed important uncertainty, which was expected. There is, however, a prominent separation between ziprasidone, quetiapine and the efficiency frontier. Aripiprazole was not considered cost-effective even when its price was set at zero: CER = USD 4,102 vs. USD 3,945 (haloperidol), USD 3,616 (chlorpromazine), USD 3,646 (risperidone) and USD 3,752 (olanzapine) USD/QALY.

Conclusion: Olanzapine was considered the most cost-effective drug for the first-line treatment of schizophrenia in Brazil. Aripiprazole was dominated by risperidone and was not considered cost-effective against olanzapine.