Funding for this research was provided by:
National Natural Science Foundation of China (81670350)
Natural Science Foundation of Zhejiang Province (LQ20H020003)
Received: 24 October 2019
Accepted: 6 January 2020
First Online: 15 January 2020
Ethics approval and consent to participate
: This study was approved by the ethics committee of First Affiliated Hospital, College of Medicine, Zhejiang University on 7th July, 2019 (reference number: 2019–1094) and the need for individual consent was waived due to its retrospective nature.
: Not applicable.
: The authors declare that they have no competing interests.