1. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Chungju Hospital, Chungju, Korea.
2. Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
3. Department of Internal Medicine, Seoul Metropolitan Government, Seoul National University Boramae Medical Center, Seoul, Korea.
4. Department of Internal Medicine, The Catholic University of Korea, Yeouido St. Mary's Hospital, Seoul, Korea.
5. Department of Internal Medicine, Medical Research Center, Ewha Womans University Medical Center, Seoul, Korea.
6. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
7. Department of Internal Medicine, The Catholic University of Korea, St. Paul’s Hospital, Seoul, Korea.
8. Department of Internal Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
9. Department of Clinical Pharmacology, Konkuk University Medical Center, Seoul, Korea.
10. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Korea.
11. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Seoul, Korea.
12. Department of Internal Medicine, College of Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea.
13. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
14. Division of Pulmonary Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical School, Anyang, Korea.