Coexisting COPD Increases Mortality in Patients With Corticosteroid-Dependent Asthma: A Nationwide Population-Based Study

Chronic corticosteroid (CS) use is a risk factor for long-term mortality in asthmatic patients, and the presence of coexisting chronic obstructive pulmonary disease (COPD) is associated with a severe presentation and poor prognosis. However, the impact of coexisting COPD on long-term mortality in patients with CS-dependent asthma has not been well elucidated. This study aimed to determine the impact of coexisting COPD on long-term mortality in patients with CS-dependent asthma. A retrospective cohort of patients with CS-dependent asthma aged 40 years or older was established using records from the Korean National Health Insurance Service database for 2005 to 2015. We classified the subjects into 2 groups according to the presence of COPD and evaluated the hazard ratio (HR) for all-cause mortality in patients with COPD relative to those without COPD. Of 8,021 patients with CS-dependent asthma, 3,121 (38.9%) had COPD. All-cause mortality was significantly greater in patients with CS-dependent asthma and COPD than in those without COPD (9,955/100,000 person-years vs. 5,585/100,100 person-years, < 0.001). The adjusted HRs were 1.29 (95% confidence interval [CI], 1.21-1.38), and the associations were especially significant for chronic lower respiratory diseases (subdistribution HR, 2.30; 95% CI, 2.06-2.57) and lung cancer (subdistribution HR, 1.34; 95% CI, 1.02-1.78). In this population-based retrospective cohort study, the presence of physician-recognized COPD was associated with greater all-cause mortality and greater risk of mortality due to chronic lower respiratory diseases and lung cancer in patients with CS-dependent asthma. Early recognition and appropriate management of COPD can improve treatment outcomes in patients with CS-dependent asthma.