Text and Data Mining valid from 2020-04-15
Received: 12 October 2019
Accepted: 5 April 2020
First Online: 15 April 2020
Ethics approval and consent to participate
: Ethical approval to conduct the study was obtained from Institutional Review Board of the Ewha University Medical Center (EUMC 2018–04–035-001). The need for consent was waived due to the anonymized nature of the data material used.
: Not applicable.
: The authors declare that they have no competing interests.