Funding for this research was provided by:
National Research Foundation of Korea (NRF-2017R1D1A3B03031940)
Text and Data Mining valid from 2019-07-10
Received: 11 February 2019
Accepted: 6 July 2019
First Online: 10 July 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Hallym University Dongtan Sacred Heart Hospital (IRB Nos. 2013-030, 2017-08-007).
: Not applicable.
: The authors declare that they have no competing interests.