The burden and predictors of latent tuberculosis infection among immigrants in South Korea: a retrospective cross-sectional study

A Quasi-experimental Study on the Effect of Pre-entry Tuberculosis Screening for Immigrants on Treatment Outcomes in South Korea: A Difference-in-Differences Analysis

OBJECTIVE

This study ascertains the effects of the pre-entry tuberculosis (TB) screening policy, which was implemented as a strategy for managing TB among immigrants, on the treatment outcomes of immigrants in South Korea.

METHODS

This study linked three different datasets from 2013 to 2018, namely (1) Korean National Tuberculosis Surveillance System; (2) National Health Information Database for patients diagnosed with TB with ICD code A15-A19, B90, or U84.3; and (3) Statistics Korea database related to cause of deaths. To identify the effect of the policy, cohorts comprising Korean and immigrant TB patients notified before (January 1, 2013-December 31, 2015) and after (September 1, 2016-December 31, 2018), the implementations of the policy were established. A difference-in-differences (DID) analysis of the treatment success and mortality rates was performed.

RESULTS

Data from 100,262 TB patients were included in the analysis (before policy implementation: 1240 immigrants and 65,723 Koreans; after policy implementation: 256 immigrants and 33,043 Koreans). The propensity score matching-DID analysis results showed that the difference in the treatment success rate between immigrants and Koreans decreased significantly, from 16% before to 6% after the policy implementation. The difference in the mortality rate between the two groups decreased from - 3% before to - 1% after the policy implementation; however, this difference was insignificant.

CONCLUSION

The treatment outcomes of immigrant TB patients in South Korea improved after the implementation of the pre-entry active TB screening policy. Future immigrant TB policies should consider establishing active patient support strategies and a healthcare collaboration system between countries.

Gender differences in tuberculosis patients with comorbidity: A cross-sectional study using national surveillance data and national health insurance claims data in South Korea

The coexistence of tuberculosis and other chronic diseases complicates disease management. Particularly, the lack of information on the difference in the prevalence of chronic diseases in tuberculosis based on age and gender can hinder the establishment of appropriate public health strategies. This study aimed to identify age- and gender-based differences in the prevalence of chronic diseases as comorbidities in patients with tuberculosis. An anonymized data source was established by linking the national health insurance claims data to the Korean national tuberculosis surveillance data from 2014 to 2018. The prevalence of chronic diseases was stratified by gender and age (age groups: ≤64, 65-74, and ≥75 years), and the differences in the prevalence of chronic diseases were analyzed by multinomial logistic regression and classified using the Charlson Comorbidity Index. A total of 148,055 patients with tuberculosis (61,199 women and 86,856 men) were included in this study. Among the patients aged ≥65 years, 48.2% were female and 38.1% were male. In this age group, the probability of chronic disease comorbidity was higher in female patients than in male patients. The prevalence of congestive heart failure and dementia as comorbidities in patients with tuberculosis increased more drastically with age in women than in men. Thus, the present study confirmed gender and age differences in the distribution of comorbidities among patients with tuberculosis. A more comprehensive gender-responsive approach for patients with tuberculosis and chronic diseases is required to alleviate the double burden of infectious diseases and non-communicable diseases in an aging society.