Text and Data Mining valid from 2020-02-14
Received: 2 July 2019
Accepted: 30 January 2020
First Online: 14 February 2020
Ethical approval and consent to participate
: This study was approved by the Institutional Review Board of Yonsei University Health System (4-2016-0105), which waived the need for informed consent.
: Get permission from all authors.
: The authors declare that they have no competing interests.