1. Digestive Disease Center and Research Institute, Department of Internal MedicineSoonchunhyang University School of Medicine Korea
2. Digestive Disease Center, Department of Internal MedicineInha University School of Medicine Korea
3. Department of Internal Medicine, Gil Medical CenterGachon University Korea
4. Digestive Disease Center, Department of Internal Medicine, Konkuk University Medical CenterKonkuk University School of Medicine Korea
5. Department of Internal Medicine, Institute of Gastroenterology, Hallym University College of MedicineHallym University Dongtan Sacred Heart Hospital Korea