1. Digestive Disease Center, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea.
2. Department of General Surgery, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea.
3. Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Gachon Gil Hospital, Gachon University College of Medicine, Incheon, Korea.
5. Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
6. Department of Internal Medicine, Chungbuk National University College of Medicine, Cheongju, Korea.
7. Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea.