Comparison of active tuberculosis case finding strategies for immigrants in South Korea: Epidemiology and cost-effectiveness analysis

Abstract

Background Tuberculosis (TB) is one of the serious infectious diseases in South Korea, reporting 49 new cases per 100,000 people and 629 multi-drug resistant (MDR) TB in 2020. We compared active case finding (ACF) with passive case finding (semi-PCF) in epidemiological characteristics, and investigated the cost-effectiveness for screening immigrants TB.

Methods ACF and semi-PCF as a VISA renewal process using chest x-ray (CXR) with additional acid fast bacilli(AFB) smear and cultures were performed. Epidemiological parameters were compared between the two strategies, and costs were collected by mixed costing. Cost-effectiveness was evaluated using a decision analysis model from the health system perspective. The primary outcome was the incremental cost-effectiveness ratio (ICER) per averted TB cases. Additional probabilistic sensitivity analysis was conducted.

Results ACF (2.02%) showed a higher TB prevalence rate than semi-PCF (0.67%) on CXR. For the subjects above 60 years old, the suspected TB rate was significantly higher in ACF (36.6%) than semi-PCF (12.2%) (P< 0.0012). ACF ($666.83) performed $20.784 higher cost than semi-PCF ($646.13), however TB progression decreased by 0.02, resulting in ICER as $948.18 per averted TB case. In sensitivity analysis, indirect cost of ACF and semi-PCF had the highest impact on ICER.

Conclusions ACF found more TB cases than semi-PCF through CXR screening, and old aged and family VISA types were more distributed in ACF than semi-PCF. ACF is considered cost-effective as a TB screening strategy for immigrants.