Correlation of Radiological Findings with Lung Function and Functional Capacity in Posttuberculosis Lung Disease: A Prospective Observational Study

Background: Posttuberculosis lung disease (PTLD) is an increasingly recognized cause of chronic respiratory morbidity despite microbiological cure. Structural abnormalities may not always correlate with functional impairment. Objectives: The objective is to evaluate radiological changes and correlate them with spirometry, diffusing capacity for carbon monoxide (DLCO), dyspnea grading, and functional capacity in treated pulmonary tuberculosis (TB) patients. Methodology: This prospective observational study included 50 patients with previously treated pulmonary TB. All patients underwent spirometry, DLCO measurement, high-resolution computed tomography thorax, Modified Medical Research Council (mMRC) dyspnea grading, and 6-min walk test. Correlations between radiological extent and functional parameters were analyzed. Results: Spirometry abnormalities were present in 76% of patients, with obstruction being the most common pattern (71%). DLCO impairment was observed in 94% of patients. No statistically significant correlation was found between the number of pulmonary segments involved and spirometry, DLCO, mMRC grade, or 6-min walk distance (6MWD). However, spirometry severity showed a significant correlation with 6MWD distance. Dyspnea was the most common symptom (90%). Tobacco smoking (70% males) and biomass exposure (75% females) were highly prevalent. Conclusion: PTLD is associated with significant functional impairment. Radiological extent alone does not predict functional severity, highlighting the importance of comprehensive functional assessment.