Risk of tuberculosis and uptake rates of latent tuberculosis infection screening among clinical risk groups in South Korea: A nationwide population-based cohort study

BackgroundThis study aimed to investigate actual tuberculosis (TB) risk and uptake rates of latent tuberculosis infection (LTBI) screening among eight clinical risk groups specified in Korean guidelines. Proportions of potentially preventable TB in these groups were also calculated. Methods and FindingsPatients enrolled before January 1st, 2018, were classified into a prevalence cohort whereas those enrolled thereafter were classified into an incidence cohort. Both cohorts were followed up until December 31st, 2020. Sex, age, and calendar year-adjusted standardized incidence ratio (SIR) of tuberculosis was calculated with total population in South Korea as a reference group. The number of TB patients notified in 2018 was investigated for both prevalence and incidence cohorts. SIR of TB in each incidence cohort was higher than that in each corresponding prevalence cohort. Among all incidence cohorts, SIR in people living with human immunodeficiency virus (PLHIV) was the highest (17.41, (95% CI: 14.14-21.43)). Although classified as moderate TB risk diseases in current guideline, end-stage renal disease (ESRD) (8.05, (7.02-9.23)) and uncontrolled diabetes mellitus (DM) (6.31, (5.78-6.99)) showed high SIRs comparable to other high-risk diseases. Among total TB cases notified in 2018, each cohort accounted for less than 1.5% except for patients with DM. The uptake rate of LTBI test was the highest among patients using TNF inhibitors (92.7%), followed by those who underwent organ transplantation (60.4%) and PLHIV (41.3%). ConclusionsLTBI screening should be reinforced for certain clinical risk groups such as ESRD or uncontrolled DM. Beyond the current guideline, additional high-risk groups should be identified.