We aimed to review the current data composition of the Korean Tuberculosis and Post-Tuberculosis Cohort, which was constructed by linking the Korean Tuberculosis Surveillance System (KNTSS; established and operated by the Korean Disease Control and Prevention Agency since 2000) and the National Health Information Database (NHID; established by the National Health Insurance Service in 2012). The following data were linked: KNTSS data pertaining to patients diagnosed with tuberculosis between 2011 and 2018, NHID data of patients with a history of tuberculosis and related diseases between 2006 and 2018, and data (obtained from the Statistics Korea database) on causes of death. Data from 300 117 tuberculosis patients (177 206 men and 122 911 women) were linked. The rate of treatment success for new cases was highest in 2015 (86.7%), with a gradual decrease thereafter. The treatment success rate for previously treated cases showed an increasing trend until 2014 (79.0%) and decreased thereafter. In total, 53 906 deaths were confirmed among tuberculosis patients included in the cohort. The Korean Tuberculosis and Post-Tuberculosis Cohort can be used to analyze different measurement variables in an integrated manner depending on the data source. Therefore, these cohort data can be used in future epidemiological studies and research on policy-effect analysis, treatment outcome analysis, and health-related behaviors such as treatment discontinuation.

Background/Aims: This study aimed to investigate the timing and predictors of death during treatment among patients with multidrug/rifampin-resistant tuberculosis (MDR/RR-TB) in South Korea. Methods: This was a retrospective cohort study that included MDR/RR-TB cases notified between 2011 and 2017 in South Korea. Results: Among 7,226 MDR/RR-TB cases, 699 (9.7%) died at a median of 167 days (IQR 51–358 d) from the initiation of MDR-TB treatment. The cumulative proportion of all-cause death was 35.5% at 90 days and 52.8% at 180 days from treatment initiation. TB-related deaths occurred at a median of 133 days (IQR 32–366 d), which was significantly earlier than the median of 184 days (IQR 68–356 d) for non-TB-related deaths (p = 0.002). In a multivariate analysis, older age was the factor most strongly associated with death, with those aged ≥ 75 years being 68 times more likely to die (aHR 68.11, 95% CI 21.75–213.26), compared those aged ≤ 24 years. In addition, male sex, comorbidities (cancer, human immunodeficiency virus, and end stage renal disease), the lowest household income class, and TB-specific factors (previous history of TB treatment, smear positivity, and fluoroquinolone resistance) were identified as independent predictors of all-cause death. Conclusions This nationwide study highlights increased deaths during the intensive phase and identifies high-risk groups including older people and those with comorbidities or socioeconomic vulnerabilities. An integrated and comprehensive strategy is required to reduce mortality in patients with MDR/RR-TB, particularly focusing on the early stages of treatment and target populations.

Background/Aims: To determine whether metformin, which is considered a host-directed therapy for tuberculosis (TB), is effective in improving the prognosis of patients with TB and diabetes mellitus (DM), who have higher mortality than those without DM. Methods: This cohort study included patients who were registered as having TB in the National Tuberculosis Surveillance System. The medical and death records of matched patients were obtained from the National Health Information Database and Statistics Korea, respectively, and data from 2011 to 2017 were collected retrospectively. We classified patients according to metformin use among participants who used diabetes drugs for more than 28 days. The primary outcome was all-cause mortality during TB treatment. Double propensity score adjustment was applied to reduce the effects of confounding and multivariable Cox proportional hazard models were used to estimate adjusted hazard ratio (aHR) with 95% confidence interval (CI). Results: The all-cause mortality rate during TB treatment was lower (9.5% vs. 12.4%, p < 0.01) in the metformin user group. The hazard of death due to all causes after double propensity score adjustment was also lower in the metformin user group (aHR 0.76, 95% CI 0.67–0.86, p < 0.01). There was no significant difference in mortality between metformin users and non-users for TB-related deaths (p = 0.22); however, there was a significant difference in the non-TB-related deaths (p < 0.01). Conclusions Metformin use in patients with TB–DM co-prevalence is associated with reduced all-cause mortality, suggesting the potential for metformin adjuvant therapy in these patients.

Background: The treatment outcomes of patients with multidrug/rifampin-resistant (MDR/RR) tuberculosis (TB) are important indicators that reflect the current status of TB management and identify the key challenges encountered by TB control programs in a country. Methods: We retrospectively evaluated the treatment outcomes as well as predictors of unfavorable outcomes in patients with MDR/RR-TB notified from 2011 to 2017, using an integrated TB database. Results: A total of 7,226 patients with MDR/RR-TB were included. The treatment success rate had significantly increased from 63.9% in 2011 to 75.1% in 2017 (P < 0.001). Among unfavorable outcomes, the proportion of patients who failed, were lost to follow up, and were not evaluated had gradually decreased (P< 0.001). In contrast, TB-related death rate was not significantly changed (P= 0.513), while the non-TB related death rate had increased from 3.2% in 2011 to 11.1% in 2017 (P < 0.001). Older age, male sex, immigrants, low household income, previous history of TB treatment, and comorbidities were independent predictors of unfavorable outcomes. Of the 5,308 patients who were successfully treated, recurrence occurred in 241 patients (4.5%) at a median 18.4 months (interquartile range, 9.2–32.4) after completion treatment. Conclusion The treatment outcomes of patients with MDR/RR-TB has gradually improved but increasing deaths during treatment is an emerging challenge for MDR-TB control in Korea. Targeted and comprehensive care is needed for vulnerable patients such as the elderly, patients with comorbidities, and those with low household incomes.

Background: Effective treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis (FQr-MDR-TB) is difficult because of the limited number of available core anti-TB drugs and high rates of resistance to anti-TB drugs other than FQs. However, few studies have examined anti-TB drugs that are effective in treating patients with FQr-MDR-TB in a real-world setting. Methods: The impact of anti-TB drug use on treatment outcomes in patients with pulmonary FQr-MDR-TB was retrospectively evaluated using a nationwide integrated TB database (Korean Tuberculosis and Post-Tuberculosis). Data from 2011 to 2017 were included. Results: The study population consisted of 1,082 patients with FQr-MDR-TB. The overall treatment outcomes were as follows: treatment success (69.7%), death (13.7%), lost to follow-up or not evaluated (12.8%), and treatment failure (3.9%). On a propensity-score-matched multivariate logistic regression analysis, the use of bedaquiline (BDQ), linezolid (LZD), levofloxacin (LFX), cycloserine (CS), ethambutol (EMB), pyrazinamide, kanamycin (KM), prothionamide (PTO), and para-aminosalicylic acid against susceptible strains increased the treatment success rate (vs. unfavorable outcomes). The use of LFX, CS, EMB, and PTO against susceptible strains decreased the mortality (vs. treatment success). Conclusion A therapeutic regimen guided by drug-susceptibility testing can improve the treatment of patients with pulmonary FQr-MDR-TB. In addition to core anti-TB drugs, such as BDQ and LZD, treatment of susceptible strains with later-generation FQs and KM may be beneficial for FQr-MDR-TB patients with limited treatment options.