Risk Factors and Prediction of Chronic Obstructive Pulmonary Disease After Pulmonary Tuberculosis: A Prospective Cohort Study

Background: Pulmonary tuberculosis (PTB) is increasingly recognized as a major precursor of chronic obstructive pulmonary disease (COPD). However, validated tools to predict the risk of COPD following PTB cure remain limited. Early identification of individuals at high risk is essential to facilitate targeted follow-up and preventive interventions. Methods: This prospective cohort study was conducted at Hunan Chest Hospital. Adults with newly diagnosed PTB who completed standard anti-tuberculosis treatment were enrolled between January and June 2023 and followed until June 2025. Follow-up assessments were performed monthly during the first 3 months, quarterly from months 6 to 12, and every 6 months thereafter, with standardized evaluation of respiratory symptoms and lung function. Incident COPD was defined as a post-bronchodilator FEV 1 /FVC ratio < 0.70. Candidate predictors spanning demographic, clinical, inflammatory, and immunological domains were initially screened using random forest ranking and least absolute shrinkage and selection operator regression, followed by multivariable logistic regression. A prediction model was developed and internally validated using bootstrap resampling. Calibration was assessed using calibration plots with 1000 bootstrap iterations, and clinical utility was evaluated by decision curve analysis. Results: During follow-up, 83 of 324 participants (25.6%) developed COPD. Older age (≥ 65 years), active smoking, cavitary PTB, invasive fungal disease, dyspnea, an elevated systemic immune–inflammation index (SII), and a reduced CD4⁺/CD8⁺ T-cell ratio were independently associated with COPD development. A prediction model incorporating these seven variables demonstrated good discrimination, with an area under the receiver operating characteristic curve of 0.806 (95% CI: 0.751– 0.861), and satisfactory calibration. Internal validation yielded a bootstrap-corrected concordance index of 0.787, indicating favorable clinical utility across a broad range of decision thresholds. Conclusion: More than one-quarter of patients developed COPD after PTB cure, highlighting the substantial burden of post-tuberculosis respiratory sequelae. The proposed prediction model enables individualized risk stratification and may support early surveillance and targeted preventive strategies, extending post-TB care beyond microbiological cure to long-term respiratory outcomes.