2.2 COVID-19 patients
We performed a retrospective study on eligible patients with COVID-19 from August 2020 to July 2021.
During the study period, 188 confirmed patients were admitted, and 109 of these patients were analysed in the present study (Supplemental table 2 ). The study was approved by the Institutional Review Board (IRB) at the Jeju National University Hospital (IRB file no. 2020-10-019), and the study design and baseline characteristics of COVID-19 patients are available in theSupplemental Data 2 .