Funding for this research was provided by:
This study was supported by a Biomedical Research Institute Grant from Pusan National University Hospital (2016-15)
Received: 29 November 2017
Accepted: 26 June 2019
First Online: 8 July 2019
Ethics approval and consent to participate
: This study was reviewed and given exempt status by the Institutional Review Board of Pusan National University Yangsan Hospital (IRB No. 05–2017-102). Informed consent was not required as the study analyzed only pre-existing de-identified data. After institutional review board approval, we obtained the data use agreement as required with the Medical Education Unit, Pusan National University School of Medicine.
: Not applicable.
: The authors declare that they have no competing interests.