Funding for this research was provided by:
natural science foundation of Zhejiang Province (Y17H130009)
Text and Data Mining valid from 2019-11-18
Received: 11 June 2019
Revised: 4 October 2019
Accepted: 8 October 2019
First Online: 18 November 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: Ethical approval was obtained in the original study.
: The requirement for informed consent was waived because of the retrospective study design.