1. Department of Internal Medicine; Catholic University of Daegu School of Medicine; Daegu Korea
2. Department of Internal Medicine; Korea University College of Medicine; Seoul Korea
3. Department of Gastroenterology and Hepatology; Soonchunhyang University School of Medicine; Bucheon Korea
4. Department of Internal Medicine; Korea University Ansan Hospital; Ansan Korea
5. Department of Internal Medicine, Institute of Gastroenterology; Yonsei University College of Medicine; Seoul Korea