Funding for this research was provided by:
National Key Research and Development Program of China (2016YFC1301501)
Article History
Received: 9 May 2019
Accepted: 2 December 2019
First Online: 6 December 2019
Ethics approval and consent to participate
: The protocol was approved by the Institutional Review Board of Beijing Tiantan Hospital. The appropriate permissions to access the patient database which provided the data for our study were granted by Beijing Tiantan Hospital.
: Not applicable.
: The authors declare no conflict of interest.