Prevalence and factors associated with sputum smear non-conversion after two months of tuberculosis treatment among smear-positive pulmonary tuberculosis patients in Rwanda: a cross-sectional study.

Background: Non-conversion of sputum smear prolongs the infectivity of pulmonary tuberculosis patients and has been associated with unfavorable tuberculosis (TB) treatment outcomes. Nevertheless, there is a limited evidence on predictors of sputum smear non-conversion among smear-positive PTB (SPPTB) patients in Rwanda. Therefore, this study aimed to determine the factors associated with sputum smear non-conversion after two months of treatment among SPPTB patients in Rwanda.

Methods: A cross-sectional study was conducted among SPPTB patients registered in the national electronic TB reporting system by all health facilities countrywide (Rwanda) from July 2019 to June 2021. Eligible patients who had completed the first two months of anti-TB treatment and with smear results at the end of the second month of treatment were included in the study. Bivariate and multivariate logistic regression analyses were done using STATA version 16 to determine the factors associated with sputum smear non-conversion. Adjusted odds ratio (OR), 95% confidence interval (CI), and p-value < 0.05 was considered statistically significant.

Results: This study included 7,211 patients. Of them, 632 (9%) patients had sputum smear non-conversion at the end of the second month of treatment. In multivariate logistic regression analysis, age groups of 20-39 years (AOR = 1.7, 95% CI: 1.0-2.8) and 40-59 years (AOR:2, 95% CI: 1.1-3.3), history of first-line TB treatment failure (AOR = 2, 95% CI: 1.1-3.6), follow-up by community health workers(CHWs) (AOR = 1.2, 95% CI: 1.0-1.5), BMI < 18.5 at TB treatment initiation (AOR = 1.5, 95% CI: 1.2-1.8), and living in Northern Province of Rwanda (AOR = 1.4, 95% CI: 1.0-2.0), were found to be significantly associated with sputum smear non-conversion after two months of treatment.

Conclusion: Sputum smear non-conversion among SPPTB patients remains low in Rwanda compared to countries of similar health care setting. Identified risk factors for sputum smear non-conversion among SPPTB patients in Rwanda were age (20-39 years, 40-59 years), history of first-line TB treatment failure, follow up by CHWs, BMI < 18.5 at TB treatment initiation and residence (Northern province).