Text and Data Mining valid from 2018-05-31
Received: 15 March 2018
Accepted: 22 May 2018
First Online: 31 May 2018
Ethics approval and consent to participate
: The study was reviewed and approved by the Ajou University Hospital Institutional Review Board. All subjects signed consent forms.
: The Institutional Review Board exempted the requirement for informed consent because we assessed on de-identified data retrospectively.
: The authors declare that they have no competing interests.
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