A Cross-sectional Study Comparing Pulmonary Function and Exercise Capacity in Posttuberculosis Sequelae Patients among Smokers and Nonsmokers.

INTRODUCTION

Post-tuberculosis (TB) lung disease is a major cause of long-term respiratory morbidity despite microbiological cure. Smoking may exert an additional detrimental effect on pulmonary function and exercise capacity in these patients; however, comparative data between smokers and nonsmokers remain limited. The study aimed to evaluate and compare pulmonary function and exercise capacity among pulmonary TB sequelae patients between smokers and nonsmokers.

METHODS

This hospital-based cross-sectional study was conducted in the Department of Pulmonary Medicine at a tertiary care hospital in Chengalpattu District, Tamil Nadu, India, from June 2024 to November 2025. A total of 110 post-TB patients (55 smokers and 55 nonsmokers) were included. Ethical approval was obtained from the Institutional Human Ethics Committee (IEC No. 994/24; dated April 22, 2024), and written informed consent was obtained. Pulmonary function was assessed using spirometry (forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC], FEV1/FVC, peak expiratory flow rate [PEFR]), and functional capacity was evaluated using the 6-min walk test and Modified Borg Dyspnea Scale. Data were analyzed using SPSS version 29, with P < 0.05 considered statistically significant.

RESULTS

The majority of participants were aged 40-60 years, with no significant age difference between the groups (P = 0.593). Smokers were predominantly male (87.3%) compared to nonsmokers (P < 0.001). Underweight status was more common among smokers (23.6% vs. 9.1%, P = 0.019). Smokers demonstrated significantly lower FEV1 (P = 0.027), FEV1% predicted (P = 0.001), FEV1/FVC ratio (P = 0.009), and PEFR (P < 0.001). Obstructive ventilatory defects were more common among smokers (43.6% vs. 23.6%, P = 0.028). Six-minute walk distance was significantly lower in smokers (398.2 ± 63.0 m) compared to nonsmokers (441.6 ± 58.5 m) (P < 0.001), and Borg dyspnea scores were significantly higher (P < 0.001).

CONCLUSION

Smoking significantly worsens pulmonary function and exercise capacity in patients with post-TB sequelae, acting as an additive risk factor for long-term respiratory impairment. Integration of smoking cessation and pulmonary rehabilitation into post-TB care is essential.