Article History
Received: 18 December 2019
Accepted: 7 February 2020
First Online: 15 March 2020
Ethics approval and consent to participate
: This study protocol was approved by the Institutional Review Board (IRB) of Severance Hospital, Yonsei University Health System, Seoul, Korea (4–2013-0661). All participants provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.