Comparison of critically ill COVID-19 and influenza patients with acute respiratory failure

Coronavirus disease 2019 (COVID-19) is one of the biggest pandemic causing acute respiratory failure (ARF) in the last century. Seasonal influenza carries high mortality, as well. The aim of this study was to compare features and outcomes of critically-ill COVID-19 and influenza patients with ARF.

Patients with COVID-19 and influenza admitted to intensive care unit with ARF were retrospectively analyzed.

Fifty-four COVID-19 and 55 influenza patients with ARF were studied. Patients with COVID-19 had 32% of hospital mortality, while those with influenza had 47% (P=0.09). Patients with influenza had higher Eastern Cooperative Oncology Group, Clinical Frailty Scale, Acute Physiology and Chronic Health Evaluation II and admission Sequential Organ Failure Assessment (SOFA) scores than COVID-19 patients (P<0.01). Secondary bacterial infection, admission acute kidney injury, procalcitonin level above 0.2 ng/ml were the independent factors distinguishing influenza from COVID-19 while prone positioning differentiated COVID-19 from influenza. Invasive mechanical ventilation (odds ratio [OR], 42.16; 95% confidence interval [CI], 9.45-187.97), admission SOFA score more than 4 (OR, 5.92; 95% CI, 1.85-18.92), malignancy (OR, 4.95; 95% CI, 1.13-21.60), and age more than 65 years (OR, 3.31; 95% CI, 0.99-11.03) were found to be independent risk factors for hospital mortality.

There were few differences in clinical features of critically-ill COVID-19 and influenza patients. Influenza cases had worse performance status and disease severity. There was no significant difference in hospital mortality rates between COVID-19 and influenza patients.