Critically ill patients with COVID-19 have worse outcomes vs. those with flu, study finds
A new study provides insights on the clinical features and outcomes of critically ill patients hospitalized with COVID-19 vs. influenza, and shows higher risk for mortality and worse outcomes in those with COVID-19.
“COVID-19 has often been compared to influenza, as both respiratory viruses lead to a wide range of presentations from mild illness to severe respiratory failure and death,” Natalie C. Cobb, MD, MPH, of the division of pulmonary, critical care and sleep medicine at the University of Washington, Seattle, and colleagues wrote in the study published online in the Annals of the American Thoracic Society. “Our study highlights important similarities as well as key differences between these two infections.”
Researchers evaluated medical records from 65 critically ill patients with COVID-19 (mean age, 60.4 years; 70.8% men; 72.3% white; 4.6% Black) and 74 patients with severe influenza A or B (mean age, 56.8 years; 56.8% men; 68.9% white; 14.9% Black). Patients included were admitted to two academic medical center ICUs from January 2019 to April 2020.
Researchers observed an in-hospital death rate of 40% in patients with COVID-19 compared with 19% in patients with influenza A or B (adjusted RR = 2.13; 95% CI, 1.24-3.63; P = .006). Higher mortality in the patients with COVID-19 was independent of patient age, sex, comorbidities and illness severity in the ICU, according to the results.
Patients with COVID-19 were more likely to be men, have a higher BMI, and have chronic kidney disease and diabetes. Patients with COVID-19 had longer median symptom duration before hospitalization. On hospital presentation, fever (40%) and lymphopenia (80%) occurred in a similar proportion of patients with COVID-19 and influenza.
Need for invasive mechanical ventilation was similar (59% in COVID-19 vs. 55% in influenza). In the COVID-19 group, 72% were ventilated for more than 7 days compared with 46% of patients with influenza (P = .21). Patients with COVID-19 also demonstrated slower improvement in blood oxygen levels and lower rates of extubation compared with patients with influenza. The researchers reported similar rates of acute kidney injury (43.1% in COVID-19 vs. 40.5% in influenza) and need for vasopressor therapy for shock (55% vs. 49%, respectively). Diagnosis of acute respiratory distress syndrome occurred in more patients with COVID-19 (63% vs. 26%; P < .001).
“The finding that ARDS may be more prevalent among critically ill patients with COVID-19 is important in understanding why there may be a mortality difference between the two diseases,” Cobb said in a press release issued by the American Thoracic Society. “We also found that patients with ARDS due to COVID-19 had a trend toward worse outcomes than ARDS patients with influenza.”
Patients with COVID-19 had longer hospital (14 days vs. 8 days) and ICU length of stay (9 days vs. 4 days) compared with patients with influenza.
The findings of this study highlight the importance of limiting COVID-19 transmission and investigating effective therapies and vaccines, according to the researchers.