Text and Data Mining valid from 2020-02-21
Received: 1 December 2019
Accepted: 14 January 2020
First Online: 21 February 2020
Ethics approval and consent to participate
: This study was approved by the Clinical Research Ethics Committee of Beijing Anzhen Hospital, Capital Medical University, and all patients were informed and agreed to participate in this study.
: Not applicable.
: The authors declare that they have no competing interests.