1. Department of Internal Medicine, Kyung Hee University Hospital at Gang DongKyung Hee University School of Medicine Seoul Korea
2. Departments of GastroenterologyDaehang Hospital Seoul Korea
3. Department of Internal Medicine, Kangdong Sacred Heart HospitalHallym University College of Medicine Seoul Korea
4. Department of Internal Medicine, Kangbuk Samsung HospitalSungkyunkwan University School of Medicine Seoul Korea
5. Departments of GastroenterologyCentral Veterans Hospital Seoul Korea
6. Division of Gastroenterology, Samsung Medical CenterSungkyunkwan University School of Medicine Seoul Korea