1. Kyung Hee University School of Medicine, Department of Pulmonology and Critical Care Medicine, Seoul, Republic of Korea;
2. The Catholic University of Korea, Department of Internal Medicine, Seoul St Mary’s Hospital, College of Medicine, Seoul, Republic of Korea;
3. Kyung Hee Univerisity Hospital at Gangdong, Department of Pulmonary and Critical Care Medicine, Seoul, Republic of Korea;
4. Soonchunhyang University Bucheon Hospital, Department of Internal Medicine, Bucheon, Republic of Korea;
5. Hallym University Sacred Heart Hospital, Department of Internal Medicine, Seoul, Republic of Korea;
6. College of Medicine, Korea University, Department of Internal Medicine, Seoul, Republic of Korea;
7. Chung Ang University Hospital Ringgold Standard Institution, Internal Medicine, Seoul, Republic of Korea