1 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2 Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Pusan National University School of Medicine, Seo-gu, Busan, Korea.
3 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, Korea.
4 Division of Pulmonary Medicine, Department of Internal Medicine, Chonnam National University Hospital, Gwangju, Korea.
5 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea.
6 Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Yonsei University Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea.
7 Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Jeonbuk National University Medical School, Jeonju, Korea.
8 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Gangdong Sacred Heart Hospital, The Hallym University, Seoul, Korea.
9 Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
10 Division of Pulmonology and Allergy, Department of Internal Medicine, Regional Center for Respiratory Disease, College of Medicine, Yeungnam University, Daegu, Korea.
11 Division of Respiratory Medicine, Department of Internal Medicine, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Korea.
12 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
13 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yeouido St. Mary`s Hospital, The Catholic University of Korea, Seoul, Korea.
14 Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea.
15 Division of Respiratory Medicine, Soonchunhyang University CheonAn Hospital, Cheonan, Chungcheongnam-do, Korea.
16 Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
17 Department of Internal Medicine, Myongji Hospital, Hanyang University College of Medicine, Gyeongji-do, Korea.
18 Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
19 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. Electronic address: chinkook77@gmail.com.