1. Department of Gastroenterology, Shenzhen Hospital of Southern Medical University, Shenzhen, Guangdong 518100, P.R. China
2. Department of Information Management Section, Bethune International Peace Hospital, Shijiazhuang, Hebei 050000, P.R. China
3. Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China