Text and Data Mining valid from 2020-01-30
Received: 22 October 2019
Accepted: 14 January 2020
First Online: 30 January 2020
Ethics approval and consent to participate
: This study is approved by the ethics committee of Beijing Chao-Yang Hospital.
: Each patient gave written informed consent for their data to be used for research and publication.
: The authors declare that they have no competing interests.