Text and Data Mining valid from 2020-01-14
Received: 24 June 2019
Accepted: 19 December 2019
First Online: 14 January 2020
Ethics approval and consent to participate
: The study was conducted in accordance with the Declaration of Helsinki. The Institutional Review Board of the Hangang Sacred Heart Hospital approved this retrospective cohort study (Approval no. 2018-070). The board waived the requirement for informed consents.
: Not applicable.
: The authors declare that they have no competing interests.