1. Second Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan
2. Second Department of Internal Medicine, Osaka Medical College, Osaka, Japan
3. Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka, Japan
4. Clinical Study Support Center, Wakayama Medical University Hospital, Wakayama, Japan
5. Second Department of Surgery, Wakayama Medical University, Wakayama, Japan