Low Treatment Success Rate Among Previously Treated Persons with Drug-susceptible Pulmonary Tuberculosis in Kampala, Uganda

Rationale: In 2017, the treatment regimen for previously treated persons with tuberculosis (TB) changed to a shorter regimen that lasts six months and consists of Isoniazid, Rifampicin, Pyrazinamide, and Ethambutol. Few studies have examined treatment success rate (TSR) among previously treated persons with TB including the associated factors.

Objective: To determine TSR and the associated factors among previously treated persons with bacteriologically confirmed pulmonary TB on a six-month treatment regimen in Kampala, Uganda.

Methods: We retrieved data (January 2012 and December 2021) across six TB clinics in the Kampala Metropolitan area for all previously treated persons with bacteriologically confirmed pulmonary TB. TSR was defined as cure or treatment completion. Frequencies and percentages for categorical data, and the mean and standard deviation for numerical data were computed. Multivariable modified Poisson regression analysis was performed to identify factors associated with TSR, reported as adjusted risk ratio (aRR) with a 95% confidence interval (CI).

Measurements And Main Results: We enrolled 230 participants with a mean age of 34.8±10.6 years. TSR was 52.2% and was associated with (MTB) sputum smear load of ≥2+ (1-10 or >10 Acid Fast Bacilli (AFB)/Field) (aRR = 0.51; 95% CI, 0.38-0.68), TB/human immunodeficiency virus (HIV) (aRR = 0.67; 95% CI, 0.51-0.88) or unknown HIV serostatus (aRR = 0.42; 95% CI, 0.26-0.68), and digital community-based directly observed therapy short-course (DOTS) (aRR = 0.42; 95% CI, 0.20-0.88).

Conclusions: The TSR among previously treated persons with bacteriologically confirmed pulmonary TB on a six-month treatment regimen is suboptimal. TSR is less likely for people with TB/HIV co-infection or unknown HIV serostatus, high MTB sputum smear load, and on digital community-based DOTs. We recommend strengthening of TB/HIV collaborative activities and people with TB with high MTB sputum smear load should receive targeted treatment support, and the contextual barriers to digital community DOTS should be addressed.