Post-Tuberculosis Lung Disease in Treated Extra-Pulmonary Tuberculosis.

BACKGROUND: Post-tuberculosis lung disease is a well-recognized sequela of pulmonary tuberculosis (PTB). Extra-pulmonary tuberculosis (EPTB) accounts for a quarter of the global tuberculosis 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 (≥18 years) with drug-sensitive PTB and EPTB recruited from outpatient clinics in India. Adult household contacts without current tuberculosis disease underwent spirometry at enrolment and served as non-tuberculosis controls. Logistic and linear regression was used to measure the association of treated EPTB with ventilatory defects and persistence of impaired lung function during post-treatment follow-up, respectively.

RESULTS: We enrolled 775 tuberculosis survivors, 275 (35%) of whom were treated for EPTB, and 502 non-tuberculosis controls. Compared to controls, EPTB was associated with lower z-scores for FEV1 (-0.37, 95%CI -0.54 to -0.20, p&#x2009;<&#x2009;0.001) and FVC (-0.46, 95%CI -0.65 to -0.26, p&#x2009;<&#x2009;0.001), and higher odds of airflow obstruction (aOR=1.58, 95%CI 0.95 to 2.61, p&#x2009;=&#x2009;0.066) and restrictive spirometry (aOR=2.16, 95%CI 1.48 to 3.15, p&#x2009;<&#x2009;0.001) at treatment completion. Lung function deficits in EPTB survivors persisted during the 1.5 years of post-treatment 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 was lower.

CONCLUSION: People treated for EPTB have persistent ventilatory defects and respiratory symptoms and should be screened for post-tuberculosis lung disease.