Post-tuberculosis lung disease in treated extra-pulmonary tuberculosis

BACKGROUND: Post-tuberculosis lung disease is a well-recognized sequela of pulmonary tuberculosis (PTB). Extra-PTB (EPTB) accounts for a quarter of the global TB burden; yet pulmonary sequelae in people treated for EPTB are unknown. METHODS: We performed spirometry at successful treatment completion and semi-annually thereafter for 1.5 years, among adults (aged 18 years and older) with drug-sensitive PTB and EPTB recruited from outpatient clinics in India. Adult household contacts without current TB disease underwent spirometry at enrollment and served as non-TB controls. Logistic and linear regression was used to measure the association of treated EPTB with ventilatory defects and persistence of impaired lung function during posttreatment follow-up, respectively. RESULTS: We enrolled 775 TB survivors; 275 (35%) of whom were treated for EPTB and 502 non-TB controls. Compared to controls, EPTB was associated with lower z scores for FEV1 (-0.37; 95% CI, -0.54 to -0.20; P < .001) and FVC (-0.46; 95% CI, -0.65 to -0.26; P < .001) and higher odds of airflow obstruction (adjusted odds ratio [aOR] = 1.58; 95% CI, 0.95-2.61; P = .066) and restrictive spirometry (aOR = 2.16; 95% CI, 1.48-3.15; P < .001) at treatment completion. Lung function deficits in EPTB survivors persisted during the 1.5 years of posttreatment follow-up and were associated with respiratory symptoms. Findings were consistent in sensitivity analyses accounting for misclassified EPTB and unmeasured confounders. Ventilatory defects in treated EPTB were phenotypically comparable to those seen in treated PTB, however their burden, severity, and likelihood of respiratory symptoms were lower. CONCLUSION: People treated for EPTB have persistent ventilatory defects and respiratory symptoms and should be screened for post-TB lung disease.