1. Department of Internal Medicine, Jeju National University Hospital; Jeju National University School of Medicine; Jeju Republic of Korea
2. Clinical Research Center for Chronic Obstructive Airway Diseases; Seoul Republic of Korea
3. Department of Pulmonary and Critical Care Medicine; Hallym University Kangdong Sacred Heart Hospital; Seoul Republic of Korea
4. Department of Convergence Medicine, Institute for Life Sciences, Asan Medical Center; University of Ulsan College of Medicine; Seoul Republic of Korea
5. Department of Pulmonary and Critical Care Medicine, Asan Medical Center; University of Ulsan College of Medicine; Seoul Republic of Korea
6. Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine; The Catholic University of Korea; Seoul Republic of Korea
7. Department of Internal Medicine, Ewha Womans University Mokdong Hospital, College of Medicine; Ewha Womans University; Seoul Republic of Korea
8. Department of Internal Medicine, CHA Bundang Medical Center; CHA University; Seongnam Republic of Korea
9. Division of Pulmonology, Department of Internal Medicine, Hanyang University Guri Hospital; Hanyang University College of Medicine; Guri Republic of Korea
10. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kangbuk Samsung Hospital; Sungkyunkwan University School of Medicine; Seoul Republic of Korea
11. Department of Internal Medicine; Konkuk University School of Medicine; Seoul Republic of Korea
12. Department of Radiology and Research Institute of Radiology, Asan Medical Center; University of Ulsan College of Medicine; Seoul Republic of Korea