Funding for this research was provided by:
National Research Foundation of Korea (2015R1C1A2A01053155)
Text and Data Mining valid from 2018-03-19
Received: 21 March 2017
Accepted: 24 January 2018
First Online: 19 March 2018
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board at Asan Medical Center, Seoul, Korea (no. 2016–0351). All participants completed written informed consents before the data collection.
: Not applicable.
: The authors declare that they have no competing interests.
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