Timing and predictors of death during treatment in patients with multidrug/rifampin-resistant tuberculosis in South Korea

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 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.