Funding for this research was provided by:
Chinese Academy of Medical Science (CAMS) Innovation Fund for Medical Sciences (2016-I2M-3-024)
Text and Data Mining valid from 2019-07-29
Received: 15 October 2018
Accepted: 19 July 2019
First Online: 29 July 2019
Ethics approval and consent to participate
: The research protocol was approved by the institutional review board of Peking Union Medical College Hospital (reference number: S-K517). Patient consent for participation was waived by the ethics committee due to the retrospective nature of the study.
: Not applicable
: The authors declare that they have no competing interests.