Funding for this research was provided by:
National Research Foundation of Korea (NRF-2016R1C1B2008557)
Ministry of Trade, Industry and Energy (10049785)
Text and Data Mining valid from 2018-03-15
Received: 10 October 2017
Accepted: 8 March 2018
First Online: 15 March 2018
Ethics approval and consent to participate
: This study was approved by the institutional board of Seoul National University Bundang Hospital (IRB number: B-1602/334–102), which waived informed consent because of its retrospective nature.
: Not applicable.
: The authors declare that they have no competing interests.
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