1. Department of Gastroenterology, Division of Medicine, Sheikh Khalifa Specialty Hospital, Ras Al Khaimah, United Arab Emirates
2. Digestive Disease Center, Department of Internal Medicine, Cheju Halla General Hospital, Jeju, Korea
3. Division of Gastroenterology, Department of Internal Medicine and Liver Research Institute, Kyungpook National University College of Medicine, Daegu, Korea
4. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
5. Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea