Affiliation: | 1. Department of Gastroenterology, Guangzhou First People's Hospital, Guangzhou Medical University, , Guangzhou, China;2. Department of Gastroenterology, Guangzhou Nansha Central Hospital, , Guangzhou, China;3. Department of Gastroenterology, Guangdong No. 2 Provincial People's Hospital, , Guangzhou, China;4. Department of Gastroenterology, Meizhou Municipal People's Hospital, , Meizhou, Guangdong Province, China |