1. Department of Hemodialysis, Guangzhou Guanggang New City Hospital , Guangzhou , Guangdong, 510030 , PR China
2. Department of Geriatrics, The First Affiliated Hospital of Guangzhou Medical University , Guangzhou , Guangdong, 510030 , PR China
3. Department of General Practice, The First Affiliated Hospital of Guangzhou Medical University , No. 151 Yanjiang West Road, Yuexiu District , Guangzhou , Guangdong, 510030 , PR China