Post-pulmonary tuberculosis lung function: a systematic review and meta-analysis

<h2>Summary</h2><h3>Background</h3> Although post-tuberculosis lung disease poses a substantial threat to individuals who have recovered from pulmonary tuberculosis, data showing objective functional impairment in such people are scarce. We did a systematic review and meta-analysis to estimate respiratory impairment after pulmonary tuberculosis disease and examine differences in ventilatory defects. <h3>Methods</h3> We systematically searched Embase, MEDLINE, and CINAHL from Jan 1, 2000, to Dec 13, 2024. We included any study design with data on lung function tests in individuals with a previous diagnosis of pulmonary tuberculosis versus healthy controls. Outcomes extracted from eligible studies included forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁ as a percentage of the predicted value (FEV₁%), FVC as a percentage of the predicted value (FVC%), and FEV₁/FVC ratio. Pre-bronchodilator values were preferentially selected. Random effects mean difference models were used when possible and standardised mean difference where it was necessary to standardise to a single scale (ie, FEV₁%, FVC%, and FEV₁/FVC ratio). Between-study heterogeneity was estimated with <i>I</i>². This study was prospectively registered with PROSPERO (CRD42021248838). <h3>Findings</h3> Of the 5594 publications found, data from 19 studies were included for meta-analyses, reporting on 75 960 individuals of whom 7447 had past pulmonary tuberculosis. All studies reporting absolute values, using various levels of adjustment or standardisation, showed that previous pulmonary tuberculosis had a negative effect across all spirometric values: FEV₁ –0·41 L (95% CI –0·51 to –0·32, <i>I</i>²=90·4%), FVC –0·25 L (–0·33 to –0·17, <i>I</i>²=80·6%), and FEV₁/FVC ratio –0·37 (–0·54 to –0·19, <i>I</i>²=92·0%). In those studies, using reference values to derive FEV₁% and FVC %, prior pulmonary tuberculosis had a pooled standardised mean difference of –0·44 (–0·60 to –0·28, <i>I</i>²=95·6%) and –0·33 (–0·54 to –0·13, <i>I</i>²=91·3%), respectively, compared with controls. <h3>Interpretation</h3> People who recover from pulmonary tuberculosis have significantly decreased lung function compared with controls, with FEV₁ more affected than FVC, giving a mixed obstructive and restrictive picture with predominantly airflow obstruction. <h3>Funding</h3> Breathing Matters.