The effect of inhaler prescription and comorbidities on the prognosis of COPD in never-smokers: A nationwide population-based study

Abstract

Background: Most clinical trials evaluating inhaler therapy in COPD have been conducted predominantly in smoking populations, and prognostic factors and therapeutic outcomes in COPD without any history of smoking were not well investigated. Therefore, this study was conducted to investigate the effect of inhaler prescription and comorbidities on the prognosis of COPD in never-smokers. Methods: A retrospective observational study was undertaken using data from the Korean National Health Insurance Service–National Sample Cohort (NHIS-NSC) Survival analyses were performed according to inhaler prescriptions and comorbidities from index date to December 31, 2019. Results: Among 2432 eligible patients, 382 (15.7%) received long-acting muscarinic antagonist(LAMA)/long-acting β2-agonist(LABA) therapy, 1780 (73.2%) received inhaled corticosteroid(ICS)/LABA, 187 (7.7%) received LAMA monotherapy, and 83 (3.4%) received LABA monotherapy. In multivariate Cox regression analysis, compared with the LAMA/LABA group, the ICS/LABA group had significantly higher all-cause (HR 1.65; 95% CI 1.22–2.24) and respiratory mortality (HR 1.72; 95% CI 1.07–2.77). Coexisting heart failure, frequent hospitalizations (≥2 times/year vs. none), and emergency room visits along with older age, male sex, and lower body mass index (BMI) were also independently associated with higher respiratory and all-cause mortality (p < 0.05). Conclusion: Our data in the cohort of non-smoking COPD suggest that LAMA/LABA therapy was associated with better survival rate compared with ICS/LABA therapy. Moreover, comorbid heart failure, frequent hospitalizations, emergency room visits, older age, male sex, and lower BMI were also independently linked to higher risks of respiratory and all-cause mortality.