Affiliation: | 1. Digestive Disease Center, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea;2. Digestive Disease Center and Research Institute, Department of Internal Medicine, Soonchunhyang University School of Medicine, Bucheon, Korea;3. Division of Gastroenterology, Department of Internal Medicine, Inje University College of Medicine, Busan, Korea;4. Division of Gastroenterology, Chung‐Ang University College of Medicine, Seoul, Korea |