1. Division of Gastroenterology and Hepatology Department of Internal Medicine Keio University School of Medicine Shinjuku‐ku Tokyo 160‐8587 Japan
2. Department of Cardiology Asahi General Hospital Asahi Chiba 289‐2511 Japan
3. Department of Pathology Asahi General Hospital Asahi Chiba 289‐2511 Japan
4. Department of Medical Informatics Kagawa University Hospital Miki‐cho Ikenobe Kagawa 761‐0793 Japan