Sputum Conversion as a Predictor to Treatment Outcome in Tuberculosis Control in Kenya

Introduction: Globally in 2017, the estimated tuberculosis (TB) morbidity stood at 10 million while 1.45 million people died due to TB. Among the contributors to the high number of adverse outcomes is delayed sputum conversion during treatment. However, little data about delayed sputum conversion in Kenya exists. The objective was to determine the relationship between month two smear conversion and treatment outcome and established associated risk factors. Method: This was a 3 year’ retrospective cohort study of Pulmonary TB patients using routinely collected data available at the National TB Program, Kenya. Non-conversion was defined as persistent sputum smear positive PTB cases at the end of two months of treatment. Chi-square test for linear trend. A multilevel binary logistic regression models was considered with county as the level-2 variable to evaluate the impact of demographic, clinical and therapeutic data on treatment outcome. Results: Average age was 35.10 (14.82). Female constituted 34%. Month 2 Sputum bacteriological non conversion was observed in 8:3% of the cases notified. Positive predictive value of the month 2 sputum smear non-conversion for unfavourable outcomes was 13:1% (95% CI: [12.4{13.9]). Adjusted for sociodemographic and clinical characteristics, the odds for unfavourable outcomes were 5.18 (95% CI: [ 4.799 - 5.595]) higher among those that had not converted at the second month. Treatment history (aOR = 1.909; 95% CI = 1.736 - 2.10); Female gender aOR(0.752 (95%CI: [0.695 - 0.815]); HIV negative aOR(0.579 ( 95%CI: [0.535 - 0.626]) and Moderate malnutrition aOR(0.800 ( 95%CI: [0.730 - 0.878]) compared to severe malnutrition; were all protective of unfavorable outcomes. Bacteriologically confirmed cases, especially men and those with identified risk factors for non-conversion, should be closely monitored throughout their treatment period.