1. 1Department of Gastroenterology, General Hospital of Shenyang Military Area, Shenyang, 110840, China
2. 2Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, China
3. 3Department of Digestive Diseases, Sanmenxia Central Hospital, Henan University of Science and Technology, Sanmenxia, China
4. 4Medical Department, The 309th Hospital of Chinese People’s Liberation Army, Beijing, China
5. 5Department of Health Statistics, Fourth Military Medical University, Xi’an, China