Association between reduced kidney function and tuberculosis treatment outcomes

Background: The association between kidney function and tuberculosis treatment outcomes remains uncertain. Methods: We analyzed a multicenter prospective cohort of adults with rifampicin-susceptible pulmonary tuberculosis enrolled in Korea between 2019 and 2021. Kidney function was categorized using baseline estimated glomerular filtration rate (eGFR) calculated with the 2021 CKD-EPI creatinine equation and grouped as preserved (eGFR ≥ 60 mL/min/1.73 m²) and reduced (eGFR < 60 mL/min/1.73 m²) kidney function. An additional analysis evaluated severely reduced kidney function (eGFR < 30 mL/min/1.73 m²). The primary endpoint was unfavorable outcome, defined as loss-to-follow-up, treatment failure, death, still-on-treatment, transfer to another treatment unit, or recurrence, analyzed using multivariable logistic regression. The secondary endpoint was failure to complete treatment within 9 months of initiation, analyzed by Cox proportional hazards model. All models adjusted for prespecified covariates, with age and sex included in all models. Results: Among 966 participants, 89 (9%) had reduced kidney function. Unfavorable outcomes were more frequent among participants with reduced kidney function (41% vs. 19%; P < 0.001). After multivariable adjustment, reduced kidney function was independently associated with unfavorable outcomes (adjusted odds ratio [aOR], 2.46; 95% confidence interval [CI], 1.49–4.02). Severely reduced kidney function showed higher odds of unfavorable outcome (aOR, 5.52; 95% CI, 2.42–13.01). Reduced kidney function was associated with failure to complete treatment within 9 months (adjusted hazard ratio, 3.07; 95% CI, 1.69–5.59). Conclusions: Reduced kidney function was independently associated with unfavorable TB treatment outcomes. Patients with impaired kidney function at the time of tuberculosis diagnosis may require closer clinical monitoring during treatment.