1. Department of Internal Medicine, Chung-Ang University Hospital, Seoul, Republic of Korea;
2. Department of Pulmonology and Critical Care Medicine, Kyung Hee University Hospital, Seoul, Republic of Korea;
3. Department of Internal Medicine, College of Medicine, Seoul St Mary’s Hospital, The Catholic University of Korea, Seoul, Republic of Korea;
4. Department of Internal Medicine, College of Medicine, Korea University Hospital, Seoul, Republic of Korea;
5. Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea;
6. Department of Internal Medicine, Hallym University Kangnam Hospital, Seoul, Republic of Korea;
7. Department of Pulmonary and Critical Care Medicine, Asan Medical Center, Seoul, Republic of Korea;
8. Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Republic of Korea;
9. Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea;
10. Department of Internal Medicine, Hanyang University Hospital, Seoul, Republic of Korea