Predictors and short-term outcomes of recurrent pulmonary tuberculosis in Kampala, Uganda: A cohort study

Abstract

Background . Recurrent tuberculosis (TB) occurring >2 years after completing treatment for a prior TB episode is most often due to reinfection with a new strain of Mycobacterium tuberculosis. Objectives . We determined the prevalence and outcome of late recurrent TB among hospitalised patients in Kampala, Uganda. Methods . We conducted a retrospective analysis of patients admitted to Mulago Hospital, who had a cough of >2 weeks’ duration and completed TB treatment >2 years prior to admission. All patients had mycobacterial culture performed on two sputum specimens and vital status ascertained 2 months post enrolment. We performed logistic regression and Cox proportional hazards modelling to identify predictors of recurrent TB and of survival, respectively. Results . Among 234 patients, 36% ( n =84) had recurrent TB. Independent predictors included younger age (adjusted odds ratio (aOR) 0.64, 95% confidence interval (CI) 0.42 - 0.97; p =0.04), chest pain >2 weeks (aOR=3.32; 95% CI 1.38 - 8.02; p =0.007), severe weight loss of ≥5 kg (aOR 4.88; 95% CI 1.66 - 14.29; p =0.004) and the presence of ≥1 WHO danger sign of severe illness (aOR=3.55; 95% CI 1.36 - 9.29; p =0.01). Two-month mortality was 17.8% (95% CI 10.5 - 29.2), and was higher among patients who were not initiated on TB treatment (aHR 16.67; 95% CI 1.18 - 200; p =0.04), those who were HIV-positive and not on antiretroviral treatment (aHR 16.99; 95% CI 1.17 - 246.47; p =0.04) and those with a history of smoking (aHR 1.20; 95% CI 1.03 - 1.40; p =0.02). Conclusion. The high prevalence of late recurrent TB likely reflects high levels of TB transmission in Kampala. Increased use of empiric TB treatment and early ART treatment initiation if HIV-positive should be considered in patients with a prior history of TB, particularly if they are young, with weight loss ≥5 kg, chest pain >2 weeks or ≥1 WHO danger sign of severe illness.