Article History
Received: 21 June 2017
Revised: 8 March 2018
Accepted: 15 March 2018
First Online: 2 May 2018
Compliance with ethical standards
:
: The scientific guarantor of this publication is Dr. Shi-Joon Yoo.
: The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
: One of the authors has significant statistical expertise.No complex statistical methods were necessary for this paper.
: Institutional Review Board approval was obtained.
: Written informed consent was waived by the Institutional Review Board.
: • retrospective• cross-sectional study, diagnostic or prognostic study, observational• performed at one institution