Funding for this research was provided by:
National Natural Science Foundation of China (81871794, 81672201)
Beijing Municipal commission of Health and Family Planning (PXM2017 026283 000002)
Text and Data Mining valid from 2019-08-28
Received: 13 December 2018
Accepted: 18 August 2019
First Online: 28 August 2019
Ethics approval and consent to participate
: This study has been approved by the Ethics Committee of the Xuanwu Hospital Capital Medical University, and the approval number is Clinical study review  014. Written informed consent was obtained from each patient prior to the study.
: All patients included in the study provided their informed consent at enrolment on the use of patients’ data for research.
: The authors declare that they have no competing interests.