Funding for this research was provided by:
Ministry of Education (2017R1D1A1B03029050)
Text and Data Mining valid from 2019-02-26
Received: 26 January 2019
Accepted: 21 February 2019
First Online: 26 February 2019
Compliance with ethical standards
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study was approved by the institutional Review Board of Severance Hospital (4-2017-0444).
: The patient’s written informed consent was waived by the approving IRB, as this was a retrospective study.