1. Division of Pulmonology, Department of Internal Medicine, Institute of Chest Diseases, Severance Hospital, and
2. Division of Pulmonary and Critical Care Medicine, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, South Korea
3. Department of Internal Medicine, Gil Medical Center, Gachon Medical School, Incheon, South Korea
4. Division of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
5. Department of Internal Medicine, School of Medicine, Inha University, Incheon, South Korea
6. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, South Korea
7. Division of Allergy and Pulmonology, Department of Internal Medicine, Bucheon St. Mary’s Hospital, School of Medicine, The Catholic University of Korea, Bucheon-si, South Korea
8. Division of Allergy and Respiratory Medicine, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon-si, South Korea
9. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam-si, South Korea
10. Division of PulmonaryMedicine, Department of Internal Medicine, Ulsan University Hospital, College of Medicine, University of Ulsan, Ulsan, South Korea
11. Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
12. Division of Pulmonary and Allergy Medicine, Department of Internal Medicine, Soonchunhyang University Hospital, Seoul, South Korea
13. Division of Pulmonary and Critical Care Medicine, Hanyang University Guri Hospital, College of Medicine, Hanyang University, Guri, South Korea
14. Division of Pulmonology, Department of Internal Medicine, Haeundae Paik Hospital, College of Medicine, Inje University, Busan, South Korea
15. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, and
16. Department of Internal Medicine, Wonju College of Medicine, Yonsei University, Wonju, South Korea
17. Department of Internal Medicine, Busan Paik Hospital, Inje University, Busan, South Korea
18. Division of Pulmonary, Department of Internal Medicine, College of Medicine, Wonkwang University, Iksan, South Korea
19. Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, South Korea
20. Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, South Korea
21. Department of Pulmonary and Critical Care Medicine, Kyung Hee Medical Center, School of Medicine, Kyung Hee University, Seoul, South Korea
22. Biostatistics Collaboration Unit, Department of Biomedical Systems Informatics, College of Medicine, Yonsei University, Seoul, South Korea
23. Department of Internal Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Kangdong Sacred Heart Hospital, Hallym University, Seoul, South Korea; and
24. Division of Pulmonary Medicine, Department of Internal Medicine, College of Medicine, Chung Ang University, Seoul, South Korea