1. Department of Gastroenterology, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea
2. Division of Gastroenterology, Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea
3. Department of Gastroenterology, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Korea
4. Division of Gastroenterology, Department of Internal Medicine, Soon Chun Hyang University Cheonan Hospital, Cheonan, Korea
5. Department of Gastroenterology, Inje University Ilsan Paik Hospital, Goyang, Korea
6. Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea
7. Department of Gastroenterology, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea
8. Digestive Disease Center, Institute for Digestive Research, Soonchunhyang University College of Medicine, Seoul, Korea
9. Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea
10. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
11. Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
12. Department of Gastroenterology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
13. Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea
14. National Evidence-based Healthcare Collaborating Agency, Seoul, Korea
15. Department of Biostatistics, Soonchunhyang University College of Medicine, Seoul, Korea
16. Department of Applied Statistics, Chung-Ang University, Seoul, Korea
17. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
18. Department of Gastroenterology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea
19. Department of Gastroenterology, CHA Gangnam Medical Center, Seoul, Korea
20. Division of Gastroenterology, Department of Internal Medicine, Soon Chun Hyang University Bucheon Hospital, Bucheon, Korea
21. Department of Internal Medicine, Hanyang University School of Medicine, Seoul, Korea, Korea