Incidence and predictors of QTC Prolongation among Drug Resistant Tuberculosis Patients Receiving Bedaquiline-based TB regimens in Uganda: A Countrywide Retrospective Cohort Study

Abstract Background Bedaquiline improves culture conversion in drug-resistant tuberculosis (DR-TB) treatment, but its main safety concern is QTc prolongation, particularly when combined with other anti-TB drugs. This study assessed the incidence and predictors of QTc prolongation among DR-TB patients receiving Bedaquiline under programmatic conditions in Uganda. Methods We conducted a retrospective cohort study using medical records from 14 DR-TB treatment sites across Uganda (January 2017–December 2022). Data on demographics, clinical characteristics, Bedaquiline-based regimens, treatment duration, and QTc intervals were collected. Incidence rates with 95% confidence interval (CI) were calculated for QTc prolongation, while modified Poisson regression was used to identify predictors of QTc prolongation. Results Data were abstracted from 532 patients, 70.9% of whom were male. The mean (SD) age was 41.4 (±15.9) years, and 34.6% were co-infected with HIV. The baseline mean (SD) QTc was 426.8 (±28.4) ms, with a median follow-up of 10.3 months (IQR: 7.2–13.5). The overall incidence of QTc prolongation was 12.0 cases per 1,000 person-months (95% CI: 10.8–16.8). Lower BMI (IRR: 0.924 95% CI: 0.860, 0.993, p-value:0.031) increases risk of QTc prolongation. Treatment success was similar among patients with and without QTc prolongation: 73.9% (51/69) vs. 68.3% (316/463), p = 0.873. Conclusions An average of 12 new cases of QTc prolongation were observed for every 1,000-person months of accumulated observation time. The recommended monthly ECG monitoring should be emphasized among patients with low baseline BMI. QTc prolongation was not linked to poor treatment outcomes.