Article History
Received: 21 January 2020
Accepted: 4 August 2020
First Online: 10 August 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board (IRB) of Seoul National University Boramae Hospital (IRB No. 07–2018-14/062). Informed consent was waived by the IRB because the KNHIS dataset was constructed after anonymization, based on the strict confidentiality guidelines of the Korean Government.
: Not applicable.
: The authors declare that they have no competing interests.