1. Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
2. Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Republic of Korea
3. Department of Gastroenterology, Korea University Guro Hospital, Seoul, Republic of Korea
4. Department of Gastroenterology, Veterans Health Service Medical Center, Seoul, Republic of Korea
5. Department of Gastroenterology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
6. Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Republic of Korea
7. Division of Gastroenterology, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea