1. Department of Internal medicine, Hanyang University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Kyungpook National University Hospital, Kyungpook National University College of Medicine, Daegu, Korea.
4. Department of Internal Medicine, Dong-A University Hospital, Dong-A University College of Medicine, Busan, Korea.
5. Department of Internal Medicine, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Pusan National University Hospital, Pusan National University College of Medicine, Busan, Korea.
7. Department of Internal Medicine, CHA Bundang Medical Center, CHA University College of Medicine, Seongnam, Korea.
8. Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.
9. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
10. Department of Internal medicine, Ajou University Hospital, Ajou University College of Medicine, Suwon, Korea.
11. Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon, Korea.
12. Department of Internal Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea.
13. Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Korea.