1 Department of Gastroenterology, Lianzhou People's Hospital, Lianzhou, 513400, Guangdong, China.
2 The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, Guangdong, China.
3 Department of Gastroenterology, Guangdong Provincial Geriatrics Institute, National Key Clinical Specialty, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong, China. Electronic address: xulishu70@163.com.