1 Evidence Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China; Health Technology Assessment Center, Evidence Based Social Science Research Center, School of Public Health, Lanzhou University, Lanzhou 730000, China; Department of Health Research Methods, Evidence and Impact, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.
2 Department of Health Research Methods, Evidence and Impact, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.
3 Michael G DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, ON, Canada.
4 Evidence Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China; Health Technology Assessment Center, Evidence Based Social Science Research Center, School of Public Health, Lanzhou University, Lanzhou 730000, China. Electronic address: yangkh-ebm@lzu.edu.cn.