Funding for this research was provided by:
Guangdong Science and Technology Department (2017B030314026)
Text and Data Mining valid from 2019-01-08
Received: 7 August 2018
Accepted: 12 December 2018
First Online: 8 January 2019
Ethics approval and consent to participate
: This study was an epidemiological study using de-identified data from the NCDB database. Therefore, consent for patient participation and study publication was not required. The study approval was waived by the ethical committee of Yale University and Sun Yat-sen Memorial Hospital.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.