Funding for this research was provided by:
National Research Foundation of Korea (NRF-2017R1C1B5076342)
Article History
Received: 11 December 2018
Accepted: 22 March 2019
First Online: 28 March 2019
Compliance with ethical standards
:
: The authors have stated that they have no conflicts of interest.
: All procedures of this study were in accordance with the ethical standards of the Institutional Research Committee and with the 1964 Helsinki declaration and its later amendments.
: This retrospective study was approved by the Institutional Review Board of Ajou University School of Medicine. Informed consent was waived owing to the retrospective nature of this study.