Funding for this research was provided by:
National Research Foundation of Korea (NRF-2018M3A9E8023857)
Received: 24 July 2019
Accepted: 21 February 2020
First Online: 2 March 2020
Ethics approval and consent to participate
: The protocol was reviewed and approved by the Institutional Review Board (IRB) of Ajou University Hospital (IRB approval no. AJIRB-MED-MDB-18-317). The IRB decided to waive the informed consent for this study because it was a retrospective study using anonymized data.
: Not applicable.
: The authors declare that they have no competing interests.