OBJECTIVES: According to World Health Organization (WHO), South Korea is the top ranked country among the Organization for Economic Cooperation and Development (OECD) countries in terms of the incidence and mortality of tuberculosis (TB) in 2015. The prevalence rate of latent TB infection (LTBI) in adults over 40 years old is estimated over 30 percent. This study aimed to evaluate the cost-effectiveness of LTBI screening using simultaneously Interferon-gamma Releasing Assay (IGRA) and chest X-ray (CXR) comparing with the current active TB screening using CXR alone in the national health screening program for the adults 40 years old.

METHODS: A Markov model was constructed to analyze cost-effectiveness of LTBI screening based on the prevalence, successful treatment and mortality rate of LTBI, drug-susceptible (DS) and multiple drug-resistant (MDR) TB. The Markov cycle was one year and its time horizon was 45 years with a discount rate of 5 percent. The transition probability of LTBI to DS TB and the specificity and sensitivity of IGRA and CXR were also applied to the model. Sensitive analyses including a scenario analysis were performed to examine the uncertainty of the parameters on the outcomes.

RESULTS: The IGRA-CXR screening would spend more 590,000 KRW (about 525 USD) to extend one life year compared to only CXR screening from the health care system perspective. In the sensitive analysis, the transition probability of LTBI to DS TB is the most influence parameter on the results. We concluded the strategy to screen and treat LTBI in advance is more cost-effective than to do DS TB from the scenario analysis in South Korea.

CONCLUSIONS: In South Korea, the national screening program to detect LTBI using IGRA-CXR for 40 years old is economically attractive. This study would provide scientific evidence to introduce the LTBI screening program in order to control TB incidence in Korea.