Adults hospitalised early in the pandemic with COVID-19 were at more than triple the risk of death than those with influenza, despite the flu patients being older and having more chronic illnesses, according to data from Spain presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) which ran from 23-26 April.
The researchers also linked COVID-19 with longer hospital and intensive care unit (ICU) stays, with its treatment costing nearly twice as much as flu treatment.
The team examined medical records of 187 flu patients (average age 76 years, 55% male) hospitalised from 2017 to 2019, and compared their data with 187 COVID-19 patients (average age 67 years, 49% male) hospitalised from March to May 2020. All COVID patients required oxygen therapy at admission.
The 30-day COVID-19 mortality rate was 15% compared with 5% for flu. The 90-day mortality rate was 19% in the COVID-19 group and 6% in flu patients. After the investigators adjusted for confounders, they found COVID-19 to raise the risk of 30-day mortality more than four times (hazard ratio [HR] 4.04; 95% confidence interval [CI], 1.86 to 8.77) and 90-day mortality more than three times (HR 3.68; 95% CI, 1.75 to 7.74) compared with flu.
Median hospital stay was 17 versus 11 days, and median ICU stay was 15 versus 10 days, with costs for critical care almost twice as high for COVID-19 patients (€21,350 vs €12,082, or $27,400 vs $15,506).
Flu patients tended to have more existing chronic illnesses and problems
performing activities of daily living than COVID-19 patients, but they were less likely to be overweight or obese.
“Our findings suggest COVID-19 is far more lethal than influenza,” said lead author Dr Inmaculada Lopez Montesinos, from the Hospital del Mar in Barcelona. “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.”
Study details
Comparison between inpatients with COVID-19 and influenza requiring oxygen therapy in a cohort study: clinical impact and resources consumption
Lopez Montesinos, Arrieta Aldea, A. Dicastillo, M.M. Montero, A. Siverio Parès, L. Sorli, M.M. Arenas, E. Sendra, E. Cañas Ruano, S. Castañeda, Pelegrin Senent, J. Gómez Junyent, J. Villar García, F. Sanchez Martinez, H. Knobel, R. Guerri, S. Gomez Zorrilla, J.P. Horcajada.
Published on PubMed.gov on 22 April 2022
Background
To compare clinical characteristics, outcomes, and resource consumption between patients admitted due to SARS-CoV-2 vs those due to influenza infection requiring oxygen therapy.
Methods
Retrospective cohort study conducted at a tertiary-care hospital. Patients requiring oxygen therapy and admitted due to seasonal influenza infection in 2017-2019 or due to SARS-CoV2 in March-May 2020 (‘first wave’) were compared. Inclusion criteria were: age older than 18- year-old, laboratory confirmed influenza or SARS-COV-2 infection, hospitalisation due to influenza or SARS-COV-2 infection and need of oxygen at admission. In both cohorts, all patients were included consecutively until reach the sample size required. Primary outcomes: 30-day mortality. Secondary outcomes: 90-day mortality, length of hospital stay, and hospitalisation costs. Sample size to detect a difference of 11% in mortality (Type-I error 0.05, power 0.8, and losses to follow-up 0.3) = 187 patients per group.
Results
The 30-day mortality rate was 15% and 5% among COVID-19 and influenza patients, respectively (p=0.001). The 90-day mortality rate was 19% in the COVID-19 group and 6% in influenza (p<0.001).
There were no differences in mortality trends among the three seasonal influenza periods studied. After adjusting for confounders, COVID-19 was found to be an independent risk factor for 30- (HR 4.04, 95%CI 1.86-8.77; <.001) and 90-day (HR 3.68, 95% CI 1.75-7.74, p=0.001) mortality.
Regarding resource consumption and costs, COVID-19 patients had longer length of both hospital [medias days, 17 (IQR 9-27) vs 11 (IQR 8-17); p=0.002] and ICU stay [median days, 15 (10-22) vs 10 (IQR 6.75-15.5); p=0.014] compared with influenza patients. Cost of critical care of COVID-19 patients was almost twice the cost associated with the influenza group (p<0.001). Pharmacy treatment and complementary tests costs were also significantly higher in the COVID-19 group.
Conclusions
Despite influenza patients being older and being more comorbid, SARS-CoV-2 patients requiring oxygen therapy presented worse clinical and economical outcomes in our cohort.
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