Funding for this research was provided by:
National Research Foundation of Korea (NRF-2019R1I1A1A01046493, NRF-2016R1D1A1B03931637)
Received: 9 January 2020
Accepted: 28 April 2020
First Online: 15 May 2020
Ethics approval and consent to participate
: This study was performed according to the recommendations of the Declaration of Helsinki and approved by the Institutional Review Board of Chungnam National University Hospital (CNUH 2015-10-052).
: Not applicable.
: The authors have declared no conflicting interests.