Factors predicting persistent sputum smear positivity among pulmonary tuberculosis patients 2 months after treatment

SETTING: Studies have shown that adverse outcomes are more likely in patients showing persistent sputum positivity at the end of 2 months of anti-tuberculosis treatment.OBJECTIVE: To identify simple clinical, microbiological or radiological factors associated with persistent sputum positivity under national programme conditions.DESIGN: Sputum smear-positive pulmonary tuberculosis patients admitted in 2 consecutive years to a referral hospital, and who received standard short-course chemotherapy under direct observation, were reviewed retrospectively. Factors associated with persistent sputum smear positivity were analysed.RESULTS: A total of 514 patients were available for review. Logistic regression analysis showed that age groups 41-60 years and more than 60 years, numerous bacilli on initial sputum smear examination, and presence of multiple cavitary diseases were significant factors associated with persistent sputum positivity at the end of 2 months of treatment (P < 0.0001).CONCLUSIONS: Identification of high risk factors associated with persistent sputum positivity, such as specific age groups, numerous bacilli on initial sputum smear examination, and presence of multiple cavitary diseases, may be helpful in stratifying the patients according to the risk of adverse outcome, thus allowing greater efficiency in resource utilisation.