Text and Data Mining valid from 2019-02-13
Received: 2 August 2017
Accepted: 14 January 2019
First Online: 13 February 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: The Institutional Review Board of Yonsei University Health System approved this study (Y-2017-0017).
: Informed consent was obtained from all of the participants.