SEATTLE, WA — A COVID-19 patient who has been hospitalized for treatment is twice as likely to die as a patient who has been hospitalized with a severe case of influenza, according to a new study from UW Medicine.
For the study, published Friday in the Annals of the American Thoracic Society, UW researchers looked at the medical records of 65 patients who were critically ill with COVID-19, and 75 who had been hospitalized with severe influenza A or B. All patients involved had been admitted to intensive care units at UW hospitals between January 2019 and April 15, 2020.
After combing through those records, the team discovered a surprising discrepancy: 40 percent of COVID-19 patients died while hospitalized, versus just 19 percent of influenza patients. The rate remained the same regardless of the patient's age, gender, or underlying health conditions.
UW Medicine says one factor that may explain the more than double mortality rate, is the more severe impact COVID-19 has on a patient's lungs. Once hospitalized for treatment, a COVID-19 patient will require mechanical ventilation longer than a flu patient, and will have worse lung function during that time. The study found that COVID-19 patients were also more likely to develop respiratory distress syndrome, or ARDS, a potentially-deadly inflammation of the lungs.
“The finding that ARDS may be more prevalent among critically ill patients with COVID is important in understanding why there may be a mortality difference between the two diseases,” said researcher Dr. Natalie L. Cobb. “We also found that patients with ARDS due to COVID-19 had a trend toward worse clinical outcomes than ARDS patients with influenza.”
Another cause of the discrepancy may be socio-economic circumstances: COVID-19 has had a disproportionate impact on minorities and communities of color, with nearly four times as many COVID-19 patients self-identifying as Hispanic than flu patients. As a result, study authors say the higher mortality "may be related to underlying health factors as well as social and economic inequalities."
Regardless of the cause, it isn't a competition between the two diseases. Both the flu and the coronavirus can be deadly, and health experts say both need to be protected against, especially now when a surge of new coronavirus patients threatens to overrun Washington's health care system.
“With rising cases of COVID-19 and the flu season, which began in October, it is possible that we may see spikes in hospitalizations and ICU admissions that could overwhelm our healthcare system,” Cobb said. “I strongly encourage people to get the flu vaccine and continue social distancing measures and masking to limit the spread of COVID-19.”