Funding for this research was provided by:
Peking Union Medical College (2019zlgc0104)
Received: 14 January 2020
Accepted: 3 September 2020
First Online: 29 September 2020
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of Peking Union Medical College Hospital (Ref: S-K 921). The ethics committee waived the requirement for informed consent because anonymous data were analyzed retrospectively.
: Written informed consent to publish in the study was obtained from participants or their parent or legal guardian in the case of children under 16.
: The authors declare that they have no competing interests.