1. Department of Hepatology and Gastroenterology, Beijing You An Hospital, Capital Medical University, Beijing 100069, P.R. China
2. Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
3. Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, D‑68167 Mannheim, Germany