Changes in lung function according to disease extent before and after pulmonary tuberculosis

OBJECTIVE: To evaluate changes in lung function in individuals before and after treatment for pulmonary tuberculosis (PTB) in relation to extent of disease. DESIGN: Using a retrospective cohort design, changes in and predictors of lung function were evaluated. RESULTS: A total of 41 patients were included in the final analysis. The median decline in annualised forced expiratory volume in 1 sec (FEV1) was 180.0 ml/year (95%CI 118.9-356.1) in advanced PTB and 94.7 ml/year (95%CI 33.4-147.3) in localised PTB (Delta FEV1 % predicted/year 9.4%, 95%CI 4.4-14.0 vs. 3.8%, 95%CI 1.8-6.2). The median decline in annualised forced vital capacity (FVC) was 309.6 ml/year (95%CI 137.0-359.0) in advanced PTB and 101.1 ml/year (95%CI 30.3-219.6) in localised PTB (Delta FVC % predicted/year 7.3%, 95%CI 5.3-12.3 vs. 2.9%, 95%CI 0.9-6.5). CONCLUSIONS: As the sample size of our study was small, the conclusions could be biased. Nevertheless, our findings show that PTB causes a significant decline in lung function even in localised PTB, whereas advanced PTB was associated with excessive or even higher decline. This study suggests that early diagnosis and treatment of PTB is needed to preserve lung function.