Funding for this research was provided by:
National Research Foundation of Korea (2018R1C1B6005186)
Received: 4 November 2018
Accepted: 29 January 2019
First Online: 6 February 2019
Ethics approval and consent to participate
: This study was approved by the institutional review board (IRB number: UUH 2017–05-037) of Ulsan University Hospital. Prior to interview, we explained the objectives and procedures of this study to the participants and obtained an informed written consent from them.
: All participants also provided written consent for publication.
: The authors declare that they have no competing interests.
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