Cost-utility analysis of stratified isoniazid dosing by NAT2 genotype compared with isoniazid standard regimen for new patients with pulmonary tuberculosis
Abstract:
Isoniazid is metabolized by the N-acetyltransferase 2 (NAT2) enzyme. Individuals classified as slow acetylators have a higher risk of developing hepatotoxicity. This study aims to evaluate the economic and clinical impact of implementing NAT2 genotype as a strategy to prevent anti-tuberculosis drug-induced hepatitis in the Thai healthcare system. Methods: We developed a decision tree and Markov model to assess the costs, utility, and clinical outcomes of NAT2 genotypeguided isoniazid dosing compared with the standard regimen in newly diagnosed pulmonary tuberculosis patients in Thailand. The primary outcomes were costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs). Results: The analysis showed that the discounted costs were 27,423 THB, 18,083 THB discounted life-year were 10.65, 8.24 and discounted QALYs were 9.92, 7.66 years in the stratified isoniazid dosing by NAT2 genotype group and the standard regimen, respectively. ICER was 4,125 THB per QALY gained (3,867 THB per life-year gained). One-way sensitivity analysis demonstrated cost-effectiveness across all input parameters. Probabilistic sensitivity analysis indicated that 99.97% of simulations were below the willingness-to-pay threshold. Conclusions: Stratified isoniazid dosing by NAT2 genotype would be cost-effective in treatment of pulmonary tuberculosis in Thailand.