Prevalence and factors associated with non-conversion of positive sputum smears at 8 weeks of treatment among new pulmonary tuberculosis patients in kampala

Abstract

Background: Tuberculosis, despite being a curable disease, has remained a public health challenge the world over. Control of tuberculosis involves the prompt identification and cure of the infectious patients to prevent them from transmitting the disease. However, despite the intensive and adequate treatment given to the patients, some persist with a sputum smear positive with Acid Fast Bacilli. This poses a major setback in the control of tuberculosis. Objective: To determine the prevalence and factors associated with non conversion of positive sputum smears among new smear positive, pulmonary tuberculosis patients attending the CWRU-MU Research collaboration clinic. Methods: This study employed two designs; a cross-sectional to determine the prevalence and a case-control to determine the associated factors. The participants were new smear positive pulmonary tuberculosis patients who had completed 8 weeks of tuberculosis treatment, and had a 2-months sputum smear result. Cases, selected consecutively and Controls, selected randomly had a positive and negative smear result respectively, in a ratio of 1 to 3. Pretested structured data extraction forms were used to obtain information from the patients’ medical records by trained research assistants. The baseline characteristics were descriptively summarized in percentages and patient characteristics compared using the chi-square(X2) or Fischer’s exact test. Significant variables in the bivariate analysis with p< 0.2 were considered for multivariable analysis. Results: 85 out of the 393 participants that were studied remained smear positive at 2 months of anti-tuberculosis treatment, 21.6% (95%CI 20.8-25.7). On multivariable analysis factors found to be significantly associated with sputum smear non conversion included male sex (p=0.032) and a positive smoking history (p=0.047), while age was a confounder. Conclusion: The prevalence of sputum smear non conversion is high among tuberculosis patients in Kampala. Male sex and a positive smoking history are factors predictive of sputum smear non conversion; hence patients with those factors should be given special attention to accelerate their sputum clearance.