Predicting factors of treatment failure in smear positive pulmonary tuberculosis: A retrospective cohort study in Bangkok using a combination of symptoms and sputum smear/chest radiography

Background: A successful outcome of smear positive pulmonary tuberculosis [SPPTB] used as an indicator of TB control program performance is necessary for monitoring program achievement. Objective: To study outcomes of SPPTB and to investigate factors associated with treatment failure. Materials and Methods: A retrospective study was conducted to identify outcomes and factors associated with failure in HIV-seronegative, SPPTB adult patients at Prasarnmit Hospital, Bangkok, Thailand between 2003 and 2012. Results: Two hundred ninety-one patients were enrolled. The following outcomes were notes, 78.7% cure, 1.7% completed treatment, 5.5% failure, 10% transfer out, 3.8% default, and 0.3% died. In multiple logistic regression, the failures were statistically associated with age over 50 years (OR 3.99, 95% CI 1.06 to 15.07), sputum smear 3+ at diagnosis (OR 6.34, 95% CI 1.71 to 23.55), and drug resistance (OR 23.58, 95% CI 6.11 to 90.97). To predict failure, symptoms and basic laboratory results as well as sputum smear and chest radiography [CXR] were combined. The symptoms of cough, fever, and hemoptysis plus sputum smear 3+ showed high odd ratios of 5.17 (95% CI 1.50 to 18.67), 8.88 (95% CI 1.46 to 68.75), and 18.57 (95% CI 1.82 to 456.86), respectively. When combining symptoms with cavitary lesion(s) in CXR, only hemoptysis in combination with cavitary lesion(s) showed a significant association with failure (OR 8.54, 95% CI 0.87 to 205.19). Conclusion: The WHO goal of success rate in SPPTB was not achieved. However, the risk factors of failure were identified by using symptoms plus simple laboratory tests, which can be useful in resource-limited areas.