1. Department of Gastroenterology and Inflammatory Bowel Disease Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
2. Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
3. Department of Internal Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
4. Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
5. Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea
6. Department of Internal Medicine, Hansol Hospital, Seoul, Korea
7. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
8. Kangdong Seoul Colon and Rectal Surgery, Seoul, Korea
9. Department of Surgery, Yang Hospital, Seoul, Korea
10. Digestive Endoscopic Center, Seoul Song Do Colorectal Hospital, Seoul, Korea
11. Department of Gastroenterology, Daehang Hospital, Seoul, Korea
12. Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
13. Department of Internal Medicine, VHS Medical Center, Seoul, Korea
14. Department of Internal Medicine, Konkuk University Medical Center, Seoul, Korea
15. Department of Internal Medicine, National Police Hospital, Seoul, Korea
16. Jamsil Seoul Surgical Clinic, Seoul, Korea