Text and Data Mining valid from 2019-05-07
Received: 30 November 2018
Accepted: 11 April 2019
First Online: 7 May 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Seoul National University Hospital (IRB No. 1712–083-907). It was conducted according to the Declaration of Helsinki for medical research.
: Not applicable.
: The authors declare that they have no competing interests.
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