Course of illness and outcomes in older COVID-19 patients treated with HFNC: a retrospective analysis

Coronavirus disease-2019 (COVID-19) has rapidly spread worldwide and causes high mortality of elderly patients. High-flow nasal cannula therapy (HFNC) is an oxygen delivery method for severely ill patients. We retrospectively analyzed the course of illness and outcomes in 110 elderly COVID-19 patients (≥65 years) treated with HFNC from 6 hospitals. 38 patients received HFNC (200 mmHg < PaO₂/FiO₂ ≤ 300 mmHg, early HFNC group), and 72 patients received HFNC (100 mmHg < PaO₂/FiO₂ ≤ 200 mmHg, late HFNC group). There were no significant differences of sequential organ failure assessment (SOFA) scores and APECH II scores between early and late HFNC group on admission. Compared with the late HFNC group, patients in the early HFNC group had a lower likelihood of developing severe acute respiratory distress syndrome (ARDS), longer time from illness onset to severe ARDS and shorter duration of viral shedding after illness onset, as well as shorter lengths of ICU and hospital stay. 24 patients died during hospitalization, of whom 22 deaths (30.6%) were in the late HFNC group and 2 (5.3%) in the early HFNC group. The present study suggested that the outcomes were better in severely ill elderly patients with COVID-19 receiving early compared to late HFNC.