Cost-effectiveness of olanzapine in the first-line treatment of schizophrenia in China.

OBJECTIVES: This study aimed to analyse 1) the cost-effectiveness of olanzapine orally disintegrating tablet (ODT) compared to olanzapine standard oral tablet (SOT) and 2) the cost-effectiveness of olanzapine-SOT compared to aripiprazole-SOT for patients with schizophrenia in China.

METHODS: A microsimulation model was adapted from a healthcare payers' perspective. The model ran over a 1-year time horizon, using quarterly cycles. The costs of adverse events were acquired through a clinical expert panel. The average bidding prices in China of olanzapine-ODT, olanzapine-SOT, aripiprazole-SOT, and other switch alternatives were used. Inpatient and outpatient medical costs were sourced from the Urban Employee Basic Medical Insurance database in Tianjin. Additionally, adherence, efficacy, safety, and utility data were taken from literature. Uncertainty of parameters were assessed through one-way and probabilistic sensitivity analyses.

RESULTS: The total annual costs per patient in aripiprazole-SOT arm, olanzapine-SOT arm, and olanzapine-ODT arm are USD 2,296.05, USD 1,940.05, and USD 2,292.81, respectively. The average number of relapses per patient in one year in aripiprazole-SOT arm, olanzapine-SOT arm, and olanzapine-ODT arm are 0.734, 0.325, and 0.198, respectively. The quality-adjusted life years (QALYs) gained per patient in one year in aripiprazole-SOT arm, olanzapine-SOT arm, and olanzapine-ODT arm are 0.714, 0.737, and 0.758, respectively. Consequently, 1) the incremental cost-effectiveness ratios (ICERs) of administrating olanzapine-ODT over olanzapine-SOT are USD 2,791.96 per relapse avoided and USD 16,798.39 per QALY gained; and 2) the ICERs of using olanzapine-SOT over aripiprazole-SOT are USD -870.39 per relapse avoided and USD -15,477.93 per QALY gained. All ICERs are under the willingness-to-pay threshold in China of USD 25,772.67. The sensitivity analyses confirmed the robustness of the results.

CONCLUSION: As the first-line treatment for schizophrenia in China, olanzapine-ODT is cost-effective compared to olanzapine-SOT and olanzapine-SOT is cost-effective compared to aripiprazole-SOT.