Text and Data Mining valid from 2020-01-13
Received: 4 July 2019
Accepted: 11 December 2019
First Online: 13 January 2020
Ethics approval and consent to participate
: This study was conducted in accordance with the declaration of Helsinki. This study was conducted with approval from the Ethics Committee of Affiliated Hospital of Affiliated Hospital of North China University of Science and Technology. A written informed consent was obtained from all participants. The patients consented to the analysis of their medical records.
: Not applicable.
: All authors have contributed significantly to the manuscript and declare that the work is original and has not been submitted or published elsewhere. None of the authors have any financial disclosure or conflict of interest.