1. 1Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chiba, Japan.
2. 2Department of Gastroenterology, Asahi General Hospital, Chiba, Japan.
3. 3Division of Gastroenterology, Department of Internal Medicine, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan.
4. 4Department of Gastroenterology, National Hospital Organization Chiba Medical Center, Chiba, Japan.
5. 5Department of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
6. 6Division of Gastroenterology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
7. 7Biostatistics Section, Clinical Research Center, Chiba University Hospital, Chiba, Japan.
8. 8Division of Pharmacy, Chiba University Hospital, Chiba, Japan.
9. 9Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center Hospital East, Chiba, Japan.
10. 10Department of Gastroenterology, Matsudo City General Hospital, Chiba, Japan.
11. 11Department of Gastroenterology, Chiba Cancer Center, Chiba, Japan.
12. 12Department of Gastroenterology, Kimitsu Chuo Hospital, Chiba, Japan.