Received: 22 March 2020
Accepted: 30 July 2020
First Online: 12 August 2020
Ethics approval and consent to participate
: This retrospective study was approved by the Institutional Ethics Board of The Peking university Third hospital. All enrolled patients were informed and agreed to provide relevant data for this study. The methods were carried out in accordance with the relevant guidelines.
: Not applicable.
: The authors declare that they have no competing interests.