1. Department of Internal Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea
2. Department of Internal Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea
3. Department of Internal Medicine, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
4. Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
5. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
6. Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea
7. Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
8. Department of Internal Medicine, Hallym University College of Medicine, Chuncheon, Korea
9. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea
10. Department of Internal Medicine, College of Medicine, Ewha Woman’s University, Seoul, Korea
11. Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea