Article History
Received: 25 March 2021
Revised: 29 July 2021
Accepted: 3 August 2021
First Online: 18 August 2021
Declarations
:
: This retrospective chart review study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The Human Investigation Committee (IRB) of Asan medical center approved this study.
: This was a retrospective study based on records, and formal consent was not required.
: Not applicable.
: The authors declare no competing interests.