The impact of population ageing on tuberculosis incidence, mortality, and case fatality in South Korea: a nationwide retrospective study.

Background: This study investigated the effect of population ageing on the epidemiology of tuberculosis (TB) in South Korea. Methods: We conducted a retrospective cohort study using an integrated database from three national databases. We analysed trends in age-specific TB incidence, mortality, case fatality rates and risk factors for all-cause mortality among 328 637 patients with drug-susceptible TB from 2011 to 2020. Results: From 2011 to 2020, the proportion of patients aged ≥65 years increased from 30.5% to 50.7% of TB cases and from 74.3% to 86.8% of deaths. The TB incidence rate decreased from 90.3 to 39.5 per 100 000 (average annual per cent change (AAPC) -8.5%; 95% confidence interval (CI) -9.2 to -7.7). The crude mortality rate remained largely unchanged, shifting from 4.6 to 5.4 per 100 000 (AAPC 1.6%; 95% CI -0.1 to 3.1). The case fatality rate increased from 5.1% to 13.5% (AAPC 11.3%; 95% CI 10.5 to 12.1). Although incidence and mortality declined across all age groups, the rate of decline slowed with increasing age. Patients aged ≥80 years showed the slowest decline in incidence (AAPC -4.3%; 95% CI -5.4 to -3.5) and stagnation in mortality (AAPC 0.5%; 95% CI -1.4 to 2.2). Conclusions: This study highlights the challenges of population ageing on TB control, including increasing case fatality rates and slower declines in TB incidence and mortality. These findings call for a reassessment of current strategies to address the needs of the elderly.