Received: 31 July 2020
Accepted: 26 November 2020
First Online: 14 December 2020
Ethics approval and consent to participate
: This study was approved by the institutional review boards of each participating institute, and informed consent was obtained before data collection. The study has therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.1) Asan Medical Center (2015-1253)2) Gangnam Sacred Heart Hospital (2015-11-142)3) Gangnam Severance Hospital (3-2015-0227)4) Hanyang University Hospital (HYUH 2015-11-013-022)5) Korea University Anam Hospital (HRPC2016-184)6) Korea University Kuro Hospital (KUGH15358-001)7) Samsung Medical Center (SMC2015-09-057-057)8) Seoul National University Hospital (J-1408-003-599)9) Seoul National University Bundang Hospital (B-1409/266-401)10) Severance Hospital (4-2015-0929)11) Seoul National University Boramae Hospital (IRB-16-2014-36)
: Not applicable
: The authors declare that they have no competing interests.