Tuberculosis in South Korea

In South Korea, adults aged ≥65 years accounted for over half (51.3%) of new tuberculosis (TB) notifications in 2021. TB-related mortality also increases with age; however, a significant proportion of deaths among older adults is attributed to non-TB-related causes, such as underlying comorbidities. Accurately classifying the cause of death and estimating TB-related mortality are essential for understanding the disease burden and shaping effective national TB prevention and care policies.

Previous studies have highlighted the limited accuracy of identifying TB-related deaths using death certificates or data from national surveillance systems. A substantial discrepancy between TB-related death counts in the national TB surveillance system (KNTSS) and those reported by Statistics Korea has also been documented.

This nationwide retrospective cohort study examined patients with drug-susceptible TB (DS-TB) who died during treatment. The primary outcome was the agreement on the cause of death—TB-related vs. non-TB-related—based on data from both the KNTSS and Statistics Korea databases.

The median age of participants was 79 years (IQR, 70–85), with nearly half (47.5%) aged ≥80 years. Males made up 63.2% of the cohort and were younger than females (median age: 76 vs. 83 years). Regarding comorbidities, 72.0% of participants had Charlson Comorbidity Index (CCI) scores ≥3.

When stratified by TB notification year into three periods (2011–2014, 2015–2017, and 2018–2020), the median age increased over time (76 vs. 79 vs. 81 years, respectively). Among the 29,033 deaths analyzed, 12,937 (44.6%) were classified as TB-related in the Statistics Korea database, whereas only 6,028 (20.8%) were coded as such in the KNTSS—less than half the number recorded by Statistics Korea.

The overall agreement rate between the two databases regarding cause of death was 0.72 (95% CI: 0.71–0.72). This agreement improved over the study period, increasing from 0.69 in 2011 to 0.77 in 2020.

In conclusion, there is substantial disagreement between the KNTSS and Statistics Korea databases concerning TB-related deaths, although this discrepancy has lessened over time. Most of the discordant cases were classified as non-TB-related in KNTSS but as TB-related in Statistics Korea. Patient characteristics—including age, TB severity, and comorbidities—likely contributed to these inconsistencies and influenced the classification of cause of death.

Source: Chung, C., Lee, S.W., Jeong, D., Choi, H., Sohn, H., Jeon, D. and Kang, Y.A., 2025. Disagreement on estimating cause of death under tuberculosis treatment between the national tuberculosis registry and statistics data in South Korea, 2011–2020. Journal of Infection and Public Health, 18(5), p.102723.