IntroductionChronic systemic corticosteroid (CS) therapy is associated with an increased risk of mortality in patients with many chronic diseases. However, it has not been elucidated whether chronic systemic CS therapy is associated with increased mortality in patients with asthma. The aim of this study was to determine the effects of chronic systemic CS therapy on long-term mortality in adult patients with asthma.MethodsA population-based matched cohort study of males and females aged ≥18 years with asthma was performed using the Korean National Health Insurance Service database from 2005 to 2015. Hazard ratio (HR) with 95% confidence interval for all-cause mortality among patients in the CS-dependent cohort (CS use ≥6 months during baseline period) relative to those in the CS-independent cohort (CS use <6 months during baseline period) was evaluated.ResultsThe baseline cohort included 466 941 patients with asthma, of whom 8334 were CS-dependent and 458 607 were CS-independent. After 1:1 matching, 8334 subjects with CS-independent asthma were identified. The HR of mortality associated with CS-dependent asthma relative to CS-independent asthma was 2.17 (95% CI 2.04–2.31). In patients receiving low-dose CS, the HR was 1.84 (95% CI 1.69–2.00); in patients receiving high-dose CS, the HR was 2.56 (95% CI 2.35–2.80).ConclusionsIn this real-world, clinical practice, observational study, chronic use of systemic CS was associated with increased risk of mortality in patients with asthma, with a significant dose–response relationship between systemic CS use and long-term mortality.

BackgroundThere are limited data regarding the relationship between interstitial lung disease (ILD) and the natural course of coronavirus disease 2019 (COVID-19). In this study, we investigate whether patients with ILD are more susceptible to COVID-19 than those without ILD and evaluate the impact of ILD on disease severity in patients with COVID-19.MethodsA nationwide cohort of patients with COVID-19 (n=8070) and a 1:15 age-, sex-, and residence-matched cohort (n=121 050) were constructed between January 1, 2020 and May 30, 2020 in Korea. We performed a nested case-control study to compare the proportions of patients with ILD between the COVID-19 cohort and the matched cohort. Using the COVID-19 cohort, we also evaluated the risk of severe COVID-19 in patients with ILD versus those without ILD.ResultsThe proportion of patients with ILD was significantly higher in the COVID-19 cohort than in the matched cohort (0.8% versus 0.4%, p<0.001). The odds ratio [OR] of having ILD was significantly higher in the COVID-19 cohort than in the matched cohort (adjusted OR=2.02, 95% confidence interval [CI]=1.54–2.61). Among patients in the COVID-19 cohort, patients with ILD were more likely to have severe COVID-19 than patients without ILD (49.3% versus 13.1%), including mortality (13.4% versus 2.8%) (all p<0.01). The risk of severe COVID-19 was significantly higher in patients with ILD than in those without ILD (adjusted OR=2.32, 95% CI=1.24–4.01).ConclusionThe risks of COVID-19 and severe presentation were significantly higher in patients with ILD than in those without ILD.

BackgroundThe Korean Obstructive Lung Disease (KOLD) Cohort Study is a prospective longitudinal study of patients with chronic obstructive pulmonary disease (COPD), asthma, or other unclassified obstructive lung diseases. It was designed to develop new classification models and biomarkers that predict clinically relevant outcomes for patients with obstructive lung diseases.MethodsPatients over 18 years old who have chronic respiratory symptoms and airflow limitations or bronchial hyper-responsiveness were enrolled at 17 centers in South Korea. After a baseline visit, the subjects were followed up every 3 months for various assessments.ResultsFrom June 2005 to October 2013, a total of 477 subjects (433 [91%] males; 381 [80%] diagnosed with COPD) were enrolled. Analyses of the KOLD Cohort Study identified distinct phenotypes in patients with COPD, and predictors of therapeutic responses and exacerbations as well as the factors related to pulmonary hypertension in COPD. In addition, several genotypes were associated with radiological phenotypes and therapeutic responses among Korean COPD patients.ConclusionThe KOLD Cohort Study is one of the leading long-term prospective longitudinal studies investigating heterogeneity of the COPD and is expected to provide new insights for pathogenesis and the long-term progression of COPD.