Predictors of treatment failure among pulmonary tuberculosis patients in Pakistan

Objective: According to guidelines, a patient who is sputum smear positive after 5 months of treatment is declared as treatment failure. The objective of this study was to determine predictors of treatment failure at 5 months of treatment among bacteriologically positive pulmonary TB patients diagnosed in Pakistan. Methods: We analyzed retrospective treatment and follow-up data from 1053 pulmonary TB patients, diagnosed on the basis of Xpert MTB/RIF test at baseline, registered at 60 private health care centers “Sehatmand Zindagi Centers” across Pakistan from July 2017 to June 2018. Statistical analysis were carried out using Stata/IC 12 (College Station, TX: StataCorp LP). Predictors of treatment failure were determined using multiple logistic regression with sputum conversion as the outcome variable and patient demographics, baseline weight, MTB burden on Xpert at baseline and month 2 sputum smear grade as the explanatory variables. Results: A total of 1105 patients diagnosed with pulmonary TB were analyzed, of which 549 (49.7%) were males. A total of 16 (1.5%) patients were smear-positive after month 5 of treatment, of which 4 patients tested positive for Rifampicin resistance when re-tested on Xpert MTB/RIF. Sputum grade of 3+ at 2 month of treatment was strongest predictor of treatment failure in the final adjusted model for 5 month smear positivity. Age >=35 years (aOR, 1.1, 95% CI: 0.36-3.34) and medium to high MTB burden at baseline (medium aOR 1.23, 95% CI: (0.32-4.73, high aOR 2.36 (95% CI 0.63-8.79) was positively associated with predicting treatment failure. Conclusion: Sputum grade at 2 month follow up, age and MTB burden at baseline are important predictors of failure.