1. Health Technology Assessment Center/Evidence-Based Social Science Research Center, School of Public Health, Lanzhou University , Lanzhou , China
2. Evidence Based Medicine Center, School of Basic Medical Sciences, Lanzhou University , Lanzhou , China
3. Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province , Lanzhou 730000 , China
4. Health Commission of Gansu Province , Lanzhou, Gansu 730000 , China
5. Gansu Healthcare Security Administration , Lanzhou, Gansu 730000 , China
6. Department of Internal Medicine , The University of New Mexico, Albuquerque, NM 87131 , United States