Funding for this research was provided by:
Innovative Research Group Project of the National Natural Science Foundation of China (81472402)
Text and Data Mining valid from 2020-03-24
Received: 19 October 2019
Accepted: 19 March 2020
First Online: 24 March 2020
Ethics approval and consent to participate
: This study received approval from the Ethics Committee of the Xijing Hospital. Additional informed consent was not required by the ethics committee for this retrospective study.
: Not applicable.
: The authors declare that they have no competing interests.