Funding for this research was provided by:
National Natural Science Foundation of China (81872123)
Text and Data Mining valid from 2020-04-15
Received: 26 November 2019
Accepted: 2 April 2020
First Online: 15 April 2020
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of Shengjing Hospital of China Medical University. Informed consent was not needed because the study was retrospective. Patient identity and all the personal information were confidential.
: Not applicable.
: The authors declare that they have no competing interests.