Article History
Received: 10 April 2019
Revised: 10 July 2019
Accepted: 11 July 2019
First Online: 6 August 2019
Compliance with ethical standards
:
: The authors alone are responsible for the content and writing of this article.
: The authors declare that they have no conflict of interest.
: All procedures performed in the study involving human participants were in accordance with the ethical standards of the Institutional Review Board of the National Health Insurance Service Ilsan Hospital, Gyeonggi-do, Korea and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: The requirement for written informed consent was waived because of the retrospective study design.