Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Division of Gastroenterology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Ji'nan, China. Division of Gastroenterology, Affiliated Hospital of Yan'an University, Yan'an, China. Division of Gastroenterology, Luohe Hospital of Traditional Chinese Medicine, Luohe, China. Division of Gastroenterology, Luoyang First People's Hospital, Luoyang, China. Division of Gastroenterology, Lianyungang Hospital of Traditional Chinese Medicine, Lianyungang, China. Division of Gastroenterology, Jingzhou Hospital of Traditional Chinese Medicine, Jingzhou, China. Division of Gastroenterology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China. Division of Gastroenterology, Hebei PetroChina Central Hospital, Langfang, China. Division of Gastroenterology, Zhejiang University School of Medicine, Sir Run Shaw Hospital, Hangzhou, China. Division of Gastroenterology, Wangjing Hospital, Beijing, China. Division of Gastroenterology, Xinxiang First People's Hospital, Xinxiang, China. Division of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. Division of Gastroenterology, The First Affiliated Hospital of Hebei North University, Zhangjiakou, China. Division of Gastroenterology, Jilin Province People's Hospital, Changchun, China.