1. Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China
2. Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China
3. Department of Gastroenterology, University‑Town Hospital of Chongqing Medical University, Chongqing 401331, P.R. China
4. Department of Gastroenterology, Yongchuan Hospital of Chongqing Medical University, Chongqing 402160, P.R. China