Funding for this research was provided by:
National Research Foundation of Korea (NRF-2019R1A2C2010150, 2017R1E1A1A03070345)
Text and Data Mining valid from 2020-03-17
Received: 4 December 2019
Accepted: 4 March 2020
First Online: 17 March 2020
Ethics approval and consent to participate
: This study was approved by the institutional board of Ewha Womans University Mokdong Hospital (IRB number: EUMC-06-048). Informed consent was obtained from all of the patients or patients’ legal guardians.
: Not applicable
: The authors declare that they have no competing interests.