1. Department of Gastroenterology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
2. Department of Gastrointestinal Surgery, Peking University Cancer Hospital, Beijing, China
3. Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Canada
4. Centre for Health Economics and Policy Analysis, McMaster University, Hamilton, Canada