Xingshun Xu1, Shilun Ma2, Yancai Liu3. 1. Department of Internal Medicine, Jinan Maternity and Child Care Hospital, Jinan, China. 2. Second Department of Internal Medicine, the Fifth People's Hospital of Jinan, Jinan, China. 3. Second Department of Internal Medicine, the Fifth People's Hospital of Jinan, Jinan, China - lyczlg@126.com.