Factors Influencing Sputum Smear Conversion among Smear Positive Pulmonary Tuberculosis Patients in Kandahar City, Afghanistan

Introduction: Sputum conversion is an important indicator of successful Tuberculosis (TB) treatment and control program. There is no published research on sputum conversion rate and its determinants, from Afghanistan. Aim: To determine sputum smear conversion rate and identify the factors associated with delayed sputum conversion following TB treatment among smear positive pulmonary TB patients. Materials and Methods: The study was based on a secondary data analysis of a retrospective cohort of 345 newly diagnosed sputum smear positive pulmonary TB patients, from 13 public health facilities in Kandahar city, Afghanistan during the year 2017. Data was extracted in a predesigned format, which included socio-demographic, clinical, microbiological, radiological, and treatment initiation and follow-up data from TB registers. Sputum conversion rate was presented as percentage. Bivariate analysis and multiple logistic regressions were used to identify the predictors of delayed sputum conversion. Results: The mean age of the study participants was 38.3 years (SD +/- 17.6). Of the total, 165 (48%) were male and 180 (52%) were female. About 83% study participants were successfully converted to sputum smear negative at the end of the intensive phase of treatment. On bivariate analysis, age group 50 years and above, female sex, haemoptysis at the first visit, and heavy bacterial load (sputum acid fast bacilli grading 3+) were found to be associated with delayed sputum conversion. Multiple logistic regression showed that heavy sputum bacterial load (adjusted odds ratio=15.7, 95% CI=7,82-31.6) was the single independent predictor of delayed conversion. Conclusion: Higher sputum AFB grading has a greater risk of poor outcome than the patients with lower smear grading. Hence, the policy makers in Afghanistan should take a note of the results of this study to accelerate the TB control in the country.