Funding for this research was provided by:
Youth Initiative Fund of Second Military Medical University (2018QN05)
Received: 2 August 2019
Accepted: 29 October 2019
First Online: 12 November 2019
Ethics approval and consent to participate
: This retrospective study was approved by the local institutional (Committee on Ethics of Biomedicine, Second Military Medical University) review board, and written informed consent was waived for each patient.
: Not applicable
: The authors declare that they have no competing interests.