Institution: | 1.Division of Gastroenterology, Department of Internal Medicine,Korea University College of Medicine Guro Hospital,Seoul,Republic of Korea;2.Division of Gastroenterology, Department of Internal Medicine,Korea University College of Medicine Anam Hospital,Seoul,Republic of Korea;3.Division of Gastroenterology, Department of Internal Medicine,Korea University College of Medicine Ansan Hospital,Ansan-si,Republic of Korea |