COVID-19 patients hospitalized in first wave three times more likely to die than those admitted for flu, study finds

Adults hospitalized with COVID-19 during the first wave of the pandemic required longer stays and were three times as likely to die within a month compared to those hospitalized for the flu, according to a new study out of Spain.

Researchers also found evidence that suggested treating COVID-19 patients was nearly twice as costly compared with treating those with the flu.

“Our findings suggest COVID-19 is far more lethal than influenza”, lead author Dr. Inmaculada Lopez Montesinos, the Hospital del Mar in Barcelona, Spain, said in a statement.

“Despite influenza patients being older and having more comorbid illnesses, COVID-19 patients had consistently worse health outcomes and were considerably more expensive to treat. Even for those people who are lucky enough to survive COVID-19 and make it out of the hospital, they will be forever scarred by the consequences. It is vital that people get fully vaccinated and boosted against both viruses.”

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The retrospective cohort study, to be presented at the European Congress of Clinical Microbiology and Infectious Diseases, looked at 374 hospital patients who required oxygen therapy and compared a number of elements including clinical characteristics, length of stay, admission to intensive care, hospital costs, and deaths.

Half the patients had been hospitalized for seasonal influenza between 2017 and 2019. The average age for that group was 76-years-old and 55 per cent of them were male. The other 187 patients were admitted for COVID-19 infections between March and May of 2020. This group had an average age of 67 years, with 49 per cent of them male. Flu patients had more existing chronic illnesses and other challenges related to daily living than those infected with COVID-19, researchers noted.

Researchers found that 15 per cent of COVID-19 patients and five per cent of flu patients died within 30 days of hospitalization; after 90 days, the death rate was 19 per cent for COVID-19 patients and six per cent for flu.

“Since we included three seasonal influenza outbreaks, the differences in mortality are unlikely to be the result of an unusually mild influenza season,” the authors wrote in the study.

“Of note, it was necessary to review almost three periods of seasonal influenza versus two months of COVID-19 to reach the attempted sample size, reflecting the huge influx of patients in our institution during the first wave of the COVID-19 pandemic. It may be inferred that the sudden demand for hospital resources may have negatively affected care of COVID-19 cases.”

Patients with COVID-19 also had a higher risk of more severe infection and of being admitted to the ICU, according to the study, set to be published by the peer-reviewed journal Clinical Infectious Diseases by Oxford University Press.

COVID-19 patients spent an average of 14 days in the hospital compared with 11 days for flu patients, and 17 days in ICU compared with 10 days for the flu.

The average cost of critical care for COVID-19 was nearly double that of the flu, at €21,350 ($29,321) compared with €12,082 ($16,593), researchers said.

Complications like pulmonary embolism or blood clots, secondary non-respiratory infections, and acute kidney injury, were more likely to develop among COVID-19 patients, while influenza patients were more likely to develop bacterial pneumonia.

There were several limitations noted in the study, including the fact that the data was based on a single tertiary-care hospital in Spain. As a result, the findings might not be generalized to other populations, researchers cautioned. They also noted that there were no genotype studies conducted.

“These results may not therefore reflect the current scenario, in which multiple SARS-CoV-2 variants are circulating globally. Likewise, the absence of vaccinated COVID-19 patients during the study period may not reflect the current profile of inpatients with COVID-19,” the authors said.

They also noted that antivirals were used for those in the influenza group, which studies have shown decreases the mortality rate. There were no effective antiviral therapy for COVID-19 patients at the time.

“COVID-19-related hospitalization seems to be more complex and expensive than influenza, either because of greater clinical severity, length of stay, ICU bed occupancy, need for respiratory equipment, or other special measures,” the authors concluded in the paper.

“Healthcare managers should take this into account to improve healthcare activity and prepare for possible future waves of COVID-19, especially in the current scenario, where the possibility of overlapping influenza and COVID-19 epidemics could mean increased complexity in patient management.