Funding for this research was provided by:
Sanming Project of Medicine in Shenzhen (Not applicable)
Guangdong Province (Not applicable)
Text and Data Mining valid from 2019-07-05
Received: 16 January 2019
Accepted: 26 June 2019
First Online: 5 July 2019
Ethics approval and consent to participate
: The study was approved and access of raw data was granted by the Ethics Committee of the University of Hong Kong-Shenzhen Hospital. Because the study was retrospective without any interventions, the requirement for informed consent was waived.
: Not applicable.
: The authors declare that they have no competing interests.