Cost/effectiveness of aripiprazole vs. olanzapine in the long-term treatment of schizophrenia

Introduction/Objective. Although effectiveness of atypical antipsychotics in patients with schizophrenia is mostly similar, there are significant differences in adverse effects rate and treatment costs, making comparison of their cost/effectiveness ratios essential for optimal drug choice. The aim of this study was to compare cost/effectiveness of aripiprazole and olanzapine in long-term treatment of schizophrenia. Methods. A four-state, three-month cycle Markov model was built to compare aripiprazole and olanzapine. The model assumed that patients who relapse on treatment with both aripiprazole and olanzapine are further treated with clozapine. The perspective of the National Health Insurance Fund was chosen, and the period covered by the model was 10 years. The model results were obtained after Monte Carlo microsimulation of a sample with 1,000 virtual patients. Both multiple one-way and probabilistic sensitivity analysis was made. Results. After base-case analysis aripiprazole was dominated by olanzapine, as net monetary benefit was negative (-390,341.96 Ѓ} 29,131.53 RSD) and incremental cost/effectiveness ratio (ICER) was above the willingness-to-pay line of one Serbian gross domestic product per capita per quality-adjusted life year (QALY) gained. Multiple one-way and probabilistic sensitivity analysis confirmed results of the base case simulation. Conclusion. Olanzapine has more beneficial cost/effectiveness ratio than aripiprazole for long-term treatment of schizophrenia in Serbian milieu. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 175007]