Received: 10 August 2021
Accepted: 4 January 2022
First Online: 14 January 2022
: We assert that all procedures contributing to this work comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008. As the NHIS-NSC data do not contain any identifying information, the study was approved as exempt by the Institutional Review Board of Yonsei University’s Health System (4–2021-0155). Since we used the de-identified these data, the need for informed consent was waived by the Institutional Review Board of Yonsei University’s Health System (4–2021-0155).
: Not applicable.
: The authors declare that they have no competing interests.