1. Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
2. National Yang-Ming University, Taipei, Taiwan
3. Division of Hepato-Gastroenterology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City 833, Taiwan
4. Division of Gastroenterology, Department of Internal Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
5. Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
6. Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan