Cost-effectiveness of improving patients' adherence to tuberculosis treatment in South Korea using discrete event simulation

Background: Poor adherence to tuberculosis (TB) treatment is an obstacle to controlling the disease. The Korean government's national TB control plan includes a program on adherence to TB treatment to manage patients with TB. This study aimed to assess the cost-effectiveness of a national TB program for improving patient adherence. Methods: A discrete event simulation (DES) model was developed to estimate the costs and quality-adjusted life-years (QALYs) of adherent and non-adherent patients. In this model, we considered treatment completion, loss to follow-up, recurrence, death, and treatment changes from drug-susceptible to multidrug-resistant TB as clinical events. We obtained input parameters such as costs, probability of events, and time distributions for each event from the Korean National Health Insurance claims data. We estimated the costs and QALYs before implementation of the program (adherence rate = 79%) and at present (current adherence rate = 94%). The incremental cost-effectiveness ratio (ICER) was used to evaluate whether the program was cost-effective given the willingness-to-pay threshold. Results: In the simulation, the program increasing the proportion of adherent patients gained 0.018 QALY/ patient while spending $162/patient. The ICER of the TB program was $8790/QALY. Given a willingness-topay threshold of $20,000, the national TB program was considered cost-effective. Conclusion: Improvements in adherence to TB treatment through the current TB program were cost-effective. The DES model accurately reflected the real world. Commitment programs to improve patient adherence may help manage TB nationwide. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of King Saud Bin Abdulaziz University for Health Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).