Xi Li1, Harlan M Krumholz2. 1. National Clinical Research Center of Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China harlan.krumholz@yale.edu xi.li@fwoxford.org. 2. Center for Outcomes Research and Evaluation (CORE), Yale New Haven Hospital, New Haven, Connecticut, USA harlan.krumholz@yale.edu xi.li@fwoxford.org.