Prevalence and Risk Factors of Delayed Sputum Conversion among Patients Treated for Smear Positive PTB in Northwestern Rural Tanzania: A Retrospective Cohort Study

Introduction. Smear positive TB carries high morbidity and mortality. The TB treatment aims at sputum conversion by two months of antituberculous. Patients who delay sputum conversion remain potentially infectious, with risk of treatment failure, drug resistance, and mortality. Little is known about the magnitude of this problem in our setting. This study was designed to determine the prevalence and risk factors of delayed sputum conversion in northwestern rural part of Tanzania. Methods. This was a retrospective cohort study involving smear positive TB patients at Sengerema DDH in 2015. Demographic data, HIV status, and sputum results at TB diagnosis and on TB treatment were collected and analyzed using STATA 11. Results. In total, 156 patients were studied. Males were 97 (62%); the median age was 39 [30-51] years. Fifty-five (35.3%) patients were HIV coinfected and 13 (8.3%) patients had delayed sputum conversion which was strongly associated with male gender (OR = 8.2, p = 0.046), age >50 years (OR = 6.7, p = 0.003), and AFB 3+ (OR = 8.1, p = 0.008). Conclusions. Delayed sputum conversion is prevalent in this study. These patients can potentially fail on treatment, develop drug resistance, and continue spreading TB. Strategies to reduce the rate of delayed sputum conversion could also reduce these potential unfavorable outcomes.