Association of overweight with treatment outcomes in pulmonary tuberculosis

Background: While overweight has been associated with a reduced risk of developing tuberculosis and diabetes with an increased risk, it remains unclear how these conditions influence anti-tuberculosis treatment outcomes. We aimed to examine the association of overweight with anti-tuberculosis treatment outcomes, and to evaluate whether this association differs by diabetes status, using two Korean cohorts. Methods: Among patients with pulmonary tuberculosis enrolled in the multicenter prospective cohort study of pulmonary tuberculosis (COSMOTB) and the Korea Tuberculosis Cohort (KTBC) registry, we defined overweight as BMI ≥ 23 kg/m² according to national criteria and compared it with normal/underweight (BMI < 23 kg/m², per criteria). The primary and secondary outcomes were unfavorable outcomes and mortality. Multivariable regression analysis was conducted to evaluate the association of overweight with treatment outcomes, adjusting for potential confounders. Subgroup analyses were performed to assess the association in patients with and without diabetes. Results: In the COSMOTB dataset, the proportion of overweight individuals was 34.4%. Overweight was associated with a lower odds of unfavorable treatment outcome (adjusted odds ratio [aOR], 0.61; 95% confidence interval [CI], 0.37–0.97) and all-cause mortality during treatment (aOR, 0.49; 95% CI, 0.24–0.93). In subgroup analyses, these associations were observed in patients with diabetes but not in those without diabetes. In the KTBC database, overweight was also associated with reduced odds of unfavorable outcome in patients with diabetes. Conclusion: In this observational study, overweight was associated with improved treatment outcomes in pulmonary TB. This association was also significantly observed in patients with diabetes; however, causality cannot be inferred.