1. Gansu Provincial Hospital, Lanzhou, Gansu, China
2. Ningxia Medical University, Yinchuan, Ningxia, China
3. Institution of Clinical Research and Evidence-Based Medicine, the Gansu Provincial Hospital, Lanzhou, Gansu, China
4. Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu,China
5. Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, Gansu, China