1. Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu, China;
2. Department of Gastroenterology, The First Veterans Hospital of Sichuan Province, Chengdu, China;
3. Department of Gastroenterology, Chengdu Second People's Hospital, Chengdu, China;
4. Department of Gastroenterology, Yibin Second People's Hospital, Yibin, China;
5. Department of Gastroenterology, SheHong People's Hospital, Shehong, China;
6. Department of Gastroenterology, The Affiliated Huai'an No. 1 People's Hospital, Nanjing Medical University, Huaian, China.