High prevalence of COPD despite successful tuberculosis treatment

<b>Background:</b> Pulmonary tuberculosis (PTB) is associated with abnormal lung function despite microbiological cure. Few studies assess change in lung function over time or measures of diffusion capacity (DLCO) and there are no prior studies from Australia. <b>Objective:</b> Determine the prevalence and pattern of lung function impairment from a cohort of patients successfully treated for PTB, and describe how lung function changes over time. <b>Methods:</b> Observational cohort study of all patients with Mycobacterium Tuberculosis successfully treated at St Vincent’s Hospital, Sydney from 2010-2020. Sociodemographic and baseline clinical data was collected. Pulmonary function test results were evaluated at multiple timepoints including pre-treatment of PTB, on treatment and post-treatment completion. <b>Results:</b> A total of 181 patients were included in the study, 82 of which had PTB and valid lung function data were included in the analysis. Within 12 months of treatment completion, 6/30 patients (20%) had an obstructive defect, which 83.3% had moderate grade severity of COPD. Beyond 12 months, 9/27 (33.3%) had an obstructive defect with 44.4% moderate to severe grade of COPD. All patients (100%) post PTB treatment completion had impaired DLCO. Just 6 patients with lung function available pre TB diagnosis, with 4 non-transplant patients losing a mean 175 mL of FEV1 as a result of their TB episode. <b>Conclusions:</b> There is a significant prevalence of impaired lung function despite microbiological cure in this cohort of PTB patients from Australia. Of concern, there was a high rate of COPD which persisted beyond 12 months of completing PTB treatment. These findings demonstrate the importance of lung function assessment and follow up of PTB patients.