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Article History

Received: 18 October 2020

Accepted: 27 January 2021

First Online: 11 February 2021

Ethics approval and consent to participate

: This study was reviewed and approved by the Institutional Review Board of the Asan Medical Center (Approval number: 2018-0971). Informed consent was waived by the IRB because it used existing database that were provided in a de-identified format. All methods were carried out in accordance with relevant guidelines and regulations.

: Not applicable.

: The authors declare that thy have no competing interests.