Received: 7 July 2020
Accepted: 22 October 2020
First Online: 29 October 2020
Ethics approval and consent to participate
: This study complied with the tenets of the Declaration of Helsinki. Because our study was performed in a retrospective manner, a local ethics committee (Ethics Committee of Yao Municipal Hospital) ruled that no formal ethics approval or consent was required in this study. The director of our hospital granted permission to access and use the raw data.
: Not Applicable.
: The authors have no financial or other relations that could lead to a conflict of interest.