Change in pulmonary function among patients with bronchiectasis with or without non-tuberculous mycobacterial pulmonary disease

Abstract

Background: The pulmonary function of patients with bronchiectasis (BE) deteriorates with time. However, the impact of non-tuberculous mycobacterial pulmonary disease (NTM-PD) on the longitudinal changes in pulmonary function in patients with BE has not been evaluated. Aim: This study was performed to compare the longitudinal changes in pulmonary function in patients with BE according to the presence or absence of NTM-PD. Methods: Patients with non-NTM BE and nodular bronchiectatic NTM-PD who underwent spirometry at least twice from 1 July 2011 to 31 December 2018 were included. The annual rates of decline in the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and diffusing lung capacity (DLCO) were compared. The mean rates of decline were compared using the t-test, and the impact of NTM-PD on the rates of decline was elucidated using linear regression. Results: In total, 153 patients with NTM-PD and 78 patients with non-NTM BE were included in the analysis. The annual rate of decline in FEV1 was not different between patients with NTM-PD (51.5 ml/year; 95% CI, 44.1–58.8) and those with non-NTM BE (46.5 ml/year; 95% CI, 15.0–77.9) (P=0.59). Similarly, the annual rates of decline in FVC (39.4 ml in NTM-PD vs. 59.8 ml in non-NTM BE, P=0.196) and DLCO (1.5% in NTM-PD vs. 2.3% in non-NTM BE, P=0.328) were not significantly different. The presence of NTM-PD did not affect the changes in FEV1 (coefficient, 5.00; P=0.687), FVC (coefficient, −20.34; P=0.196), or DLCO (coefficient, −0.86; P=0.327). Conclusion: The presence of NTM-PD did not affect the changes in pulmonary function over time in patients with BE.