Chronic obstructive pulmonary disease is a risk factor for non-tuberculous mycobacterial pulmonary disease: a population-based matched cohort study

Background Longitudinal studies comprehensively evaluating the direction of the relationship between chronic obstructive pulmonary disease (COPD) and nontuberculous mycobacterial pulmonary disease (NTM-PD) are scarce. Therefore, this study aimed to evaluate whether COPD influences the development of NTM-PD even after considering various confounders by using a nationwide longitudinal cohort study. Methods Data from the National Health Insurance Service National Sample Cohort between 2002 and 2019 were analysed. Participants≥20 years of age with COPD and no previous NTM diagnosis were included in the study. The incidence of NTM-PD was compared between participants with COPD (n=8939) and 1:4 fully matched control participants (n=32 355). Participants were followed until the date of NTM-PD incidence, death, or December 2019. Results During a median follow-up of 9.0 years (IQR, 5.0–12.9 years), participants with COPD (55.5 per 100 000 person-years) had a higher incidence of NTM-PD than matched control cohorts (25.4 per 100 000 person-years), with a HR of 2.16 (95% CI, 1.45 to 3.23). Age, sex, smoking history, asthma, bronchiectasis and corticosteroid use did not affect the association between COPD and the risk of incident NTM-PD (P for interaction >0.05 for all). Among patients with COPD, being underweight and having bronchiectasis were significantly associated with NTM-PD development. Conclusions Individuals with COPD had approximately a twofold increased risk of developing NTM-PD compared with matched controls. Being underweight and having bronchiectasis were identified as risk factors for developing NTM-PD.