Zhao, Quchuan
Chi, Tianyu
Article History
Received: 28 December 2020
Accepted: 31 May 2021
First Online: 6 June 2021
Declarations
:
: The study protocol was done in accordance to the ethical guidelines of the 1975 Helsinki Declaration. This study protocol was approved by the ethics committee of Xuanwu Hospital of Capital Medical University. Informed consent was waived as the data used in this study were anonymized, which was approved by the ethics committee at our hospital.
: Not applicable.
: The authors declare that they have no competing interests.