Funding for this research was provided by:
Korea University Ansan Hospital Grant
Received: 30 December 2018
Accepted: 31 October 2019
First Online: 21 November 2019
Ethics approval and consent to participate
: The protocol used in this study was approved by the Institutional Review Board of the Korea University Ansan Hospital (IRB number: 2017AS0014). Informed consent was not required for this study as all the data was obtained from medical records.
: Not applicable.
: The authors declare that they have no competing interests.