Funding for this research was provided by:
Ministry of Education (NRF-2015R1D1A1A01058075)
Ministry of Health and Welfare (HI14C1277)
Received: 24 August 2018
Accepted: 3 July 2019
First Online: 15 July 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board (IRB) of Seoul National University Hospital (IRB No.1612–086-815). Informed consent was waived due to the retrospective nature of this study.
: Not applicable.
: The authors declare that they have no competing interests.