1. Division of Pulmonology and Critical Care Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea
2. Pulmonary, Allergy and Critical Care Medicine, Gangneung Asan Hospital, Gangneung, South Korea
3. Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, Seoul, South Korea
4. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University Busan Paik Hospital, Busan, South Korea
5. Department of Pulmonary and Critical Care Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea
6. Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, South Korea
7. Division of Respiratory Medicine, Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, South Korea
8. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Ilsan, South Korea
9. Department of Internal Medicine, Pusan National University Hospital, Busan, South Korea
10. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Incheon, South Korea
11. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea
12. Department of Internal Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, South Korea
13. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea