1. Division of Gastroenterology, Department of Internal Medicine and Gastrointestinal Cancer Center, Kangbuk Samsung HospitalSungkyunkwan University School of Medicine Seoul Korea
2. Center for Crohn's and Colitis, Department of Gastroenterology and HepatologyKyung Hee University School of Medicine Seoul Korea
3. Division of Gastroenterology, Department of Internal MedicineKorea University Guro Hospital Seoul Korea
4. Department of Internal MedicineChonnam National University Medical School Gwangju Korea
5. Department of Internal Medicine and Liver Research InstituteSeoul National University College of Medicine Seoul Korea
6. Department of Internal MedicineHanyang University Guri Hospital Gyeonggi‐Do Korea
7. Department of Internal Medicine, Seoul Paik HospitalInje University College of Medicine Seoul Korea
8. Division of Gastroenterology and Hepatology, Department of Internal MedicineKorea University College of Medicine Seoul Korea