Wen Ren1, Ying Liu1, Yan Qiu1, Jingjing Ren2. 1. Department of General Practice, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, China. 2. Department of General Practice, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, China. Email: lisarjj@126.com.