Funding for this research was provided by:
National Natural Science Foundation of China (81600196)
Article History
Received: 6 October 2020
Accepted: 2 April 2021
First Online: 15 April 2021
Declarations
:
: Ethical approval was obtained from Beijing Friendship Hospital ethics committee. This retrospective study was conducted without informed consent for some objective reasons and was approved by the ethics committee. All procedures performed in studies were in accordance with the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.