Text and Data Mining valid from 2019-11-28
Received: 20 May 2019
Accepted: 15 October 2019
First Online: 28 November 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Ethics Board of the Hebei Medical University Third Affiliated Hospital, and informed consent was obtained from all individual participants that were included in this study.
: Not applicable.
: The authors declare that they have no competing interests.