1. Department of Internal Medicine, Pusan National University School of Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
2. Department of Internal Medicine, Soonchunhyang University Hospital Cheonan, Cheonan, Korea
3. Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
4. Digestive Disease Center, CHA Bundang Medical Center, CHA University, Seongnam, Korea
5. Department of Internal Medicine, Inha University Hospital, Inha University School of Medicine, Incheon, Korea