Text and Data Mining valid from 2020-01-15
Received: 23 July 2019
Accepted: 5 January 2020
First Online: 15 January 2020
Ethics approval and consent to participate
: This study was approved by the institutional review board of Chung-Ang University Hospital (approval number: 1810-014-16217). The need for informed consent was waived because this study was a retrospective cross-sectional study.
: Not applicable.
: The authors declare that they have no competing interests.