Structural and functional pulmonary impairment in treated cases of pulmonary tuberculosis: a cross-sectional study

Pulmonary impairment after tuberculosis treatment is seen in 40%-75% of patients despite bacteriological cure. Study aimed to find prevalence of structural and functional pulmonary impairment in a group of previously fit serving soldiers at the end of supervised institutional treatment for pulmonary tuberculosis.

Descriptive cross-sectional study was conducted in a tertiary care center on 375 newly diagnosed patients of pulmonary tuberculosis completed treatment. They underwent spirometry and chest X ray (CXR) at end of treatment. Their lung function was classified as normal or abnormal (obstructive, restrictive, or mixed pattern). Chest radiographs were reported as normal/abnormal. Logistic regression models were used to explore the factors associated with abnormal lung function.

Functional impairment was present in 145/375 (38.7%). 115/375 (30.66%) had restrictive, 24/375 (6.4%) had mixed, and 6/375 (1.6%) had obstructive pattern on spirometry, respectively. Out of the 115 patients having restrictive pattern, 103 (89.56%) had mild restriction, 11(9.56%) had moderate restriction, and 1 (0.86%) had severe restriction. Structural impairment on CXR was present in 309/375 (82.4%) of patients. Significant factors associated with pulmonary impairment in our study were time to diagnosis (>1 month) adj odds ratio (OR) = 1.71, 95% confidence interval (CI) 1.07-2.74, sputum conversion of >2 months, Adj OR 2.52, 95% CI 1.25-5.07, and sputum/culture positivity Adj OR 1.57, 95% CI 1.02-2.42. CXR abnormality was significantly associated with sputum and/culture positivity Adj OR 4.54, 95% CI 2.28-9.03.

Despite successful treatment, pulmonary impairment was present in 38.7% of patients, and structural changes evident on CXR was present in 82.4% of patients.