1. Department of General Medicine, The Affiliated Hospital of Qingdao University , No 7 Jiaxing Road, Shibei District, Qingdao 266000, Shandong, China . email: minfangbo@126.com
2. Department of General Medicine, The Affiliated Hospital of Qingdao University , No 7 Jiaxing Road, Shibei District, Qingdao 266000, Shandong, China