Funding for this research was provided by:
National Research Foundation of Korea (2016R1D1A1B03933410, 2018R1D1A1B07048821)
Received: 22 October 2020
Accepted: 31 January 2021
First Online: 11 February 2021
Ethics approval and consent to participate
: The study design was approved by the institutional review board of Gangnam CHA hospital (GCI-18-48). As a research involving the retrospective review, this study qualified a waiver of informed consent.
: Not applicable.
: The authors declare that they have no competing interests.