Text and Data Mining valid from 2018-11-26
Received: 12 June 2018
Accepted: 7 November 2018
First Online: 26 November 2018
Ethics approval and consent to participate
: This study was approved by the institutional review board of Yonsei University College of Medicine, which waived the requirement for informed consent based on the study design.
: Not applicable.
: All authors have no competing interests to declare.
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