1. Division of Gastroenterology, Department of Internal Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
2. Division of Gastroenterology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
3. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
4. Division of Gastroenterology, Department of Internal Medicine, Hallym University Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Korea
5. Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea
6. Digestive Disease Center, Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
7. Digestive Disease Center, Department of Internal Medicine, Soonchunhyang University School of Medicine, Bucheon, Korea