Chinese Evidence-based Medicine Centre, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China. Department of Endocrinology and Metabolism, West China Hospita, Chengdu. West China School of Pharmacy, Sichuan University, Chengdu. Norwegian Knowledge Centre for the Health Services, Oslo, Norway Department of Medicine, Innlandet Hospital Trust, Gjøvik, Norway. Department of Hygiene and Dietetics, Jagiellonian University Medical College, Krakow, Poland. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada Faculty of Medicine, University of Toronto, Toronto, ON, Canada. Department of Medicine, University of British Columbia, Vancouver, BC, Canada. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada Department of Anesthesia, McMaster University, Hamilton Michael G DeGroote Institute for Pain Research and Care, McMaster University, Hamilton. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada Department of Anesthesia, McMaster University, Hamilton Stanford Prevention Research Center, Department of Medicine, Stanford University, Stanford, CA, USA Department of Anaesthesia and Pain Medicine, Hospital for Sick Children, Toronto, ON Canada. Department of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru. Internal Medicine Unit, Hospital Clinico FUSAT, Rancagua, Chile. Department of Medical Administration, 363 Hospital, Chengdu, Sichuan, China. Second Hospital of Lanzhou University, Lanzhou, Gansu, China. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada Department of Medicine, McMaster University, Hamilton. Chinese Evidence-based Medicine Centre, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China sunx26@gmail.com.