Received: 18 November 2020
Accepted: 20 January 2021
First Online: 29 January 2021
Ethics approval and consent to participate
: The studies involving human participants were reviewed and approved by the Ethics Committee of General Hospital of Southern Theater Command of PLA. Because of the retrospective design and anonymous data used in the study, written informed consent was not obtained.
: Not applicable
: The authors declare that they have no competing interests.