1. Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
2. Division of Gastroenterology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
3. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Ewha Womans University College of Medicine, Seoul, Korea
4. Division of Gastroenterology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
5. Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea
6. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
7. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
8. Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea
9. Division of Gastroenterology, Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
10. Division of Gastroenterology, Department of Internal Medicine, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea