Cost-effectiveness Analysis of TPMT Genotype-guided Azathioprine Treatment Compared to Standard Treatment for Patients with Moderate/Severe Ulcerative Colitis

Abstract

This study assessed cost-effectiveness of pharmacogenomics (PGx)-based azathioprine (AZA) compared to standard AZA therapy for ulcerative colitis (UC) patients in Canada. A patient-level Microsimulation model was developed to compare the lifetime costs and quality-adjusted life years (QALYs) gained by a hypothetical cohort of UC patients with age and sex characteristics. The parameters used in the model were derived from the published literature and costs from the Ontario Schedules of Payments and published sources. The results were summarized in terms of the incremental cost-effectiveness ratio (ICER). Compared to standard AZA, PGx-based AZA care was the dominant strategy with 0.17 incremental QALYs and cost savings of CAD$2,724. The probabilistic sensitivity analysis showed that PGx-based AZA had greater probability of being cost-effective compared to standard AZA at any willingness to pay (WTP) threshold. At a WTP threshold of$50,000/QALY, PGx-based AZA was the cost-effective treatment in 97% of the iterations, while standard AZA cost-effective strategy in 3% of the iterations. We found that PGx-based AZA care presents good value for money and has a higher probability of being cost-effective for UC patients in Canada at a WTP threshold of $50,000/QALY