Funding for this research was provided by:
National Research Foundation of Korea (No. 2010-0028631)
Article History
Received: 3 September 2018
Accepted: 9 April 2019
First Online: 2 May 2019
Ethics approval and consent to participate
: This study was approved by the institutional review board (IRB) of Seoul National University Hospital (IRB number: 1309–071-521). As we used de-identified data, informed consent was exempted by the IRB.
: Not applicable.
: The authors declare that they have no competing interests.
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