Department of Gastroenterology,Peking Union Medical College Hospital,Peking Union Medical College and Chinese Academy of Medical Science,Beijing 100730,China

School of Population Medicine and Public Health,Peking Union Medical College and Chinese Academy of Medical Science,Beijing 100730,China

JC School of Public Health and Primary Care,Faculty of Medicine,The Chinese University of Hong Kong,Hong Kong Special Administrative Region,China

Emergency Department,Peking Union Medical College Hospital,Peking Union Medical College and Chinese Academy of Medical Science,Beijing 100730,China

Department of Health Research Methods,Evidence and Impact,McMaster University,Hamilton,Canada

Centre for Health Economics and Policy Analysis,McMaster University,Hamilton,Canada

State Key Laboratory of Complex Severe and Rare Diseases,Peking Union Medical College Hospital,Peking Union Medical College and Chinese Academy of Medical Science,Beijing 100730,China

Clinical Epidemiology Unit,International Clinical Epidemiology Network,Beijing 100730,China