Adults hospitalized with SARS-CoV-2 Omicron infections in Switzerland died at 1.5 times the rate of those diagnosed as having influenza A or B, shows a multicenter study published yesterday in JAMA Network Open.
A team led by University of Lucerne researchers analyzed surveillance data from a national database on 3,066 COVID-19 Omicron patients admitted to 1 of 14 hospitals from Jan 15 to Mar 15, 2022, and 2,146 flu patients admitted from Jan 1, 2018, to Mar 15, 2022. The team compared rates of 30-day all-cause death and intensive care unit (ICU) admission in the two groups.
Roughly 80% of both groups had underlying medical conditions, but fewer COVID-19 patients reported respiratory comorbidities than those with flu (13.1% vs 24.6%). Among the flu patients, 96.2% had type A, and 3.8% had type B. Of the COVID-19 patients, 51.9% had received at least one vaccine dose, and 25.2% had received three doses.
COVID not tied to higher ICU rates
A total of 214 COVID-19 patients (7.0%) died in the hospital, compared with 95 flu patients (4.4%). The final adjusted subdistribution hazard ratio (sdHR) for in-hospital COVID-19 death relative to flu was 1.54 (54% higher). Risk factors for death in both groups before versus after ICU admission were older age (median, 85 vs 71 years) and dementia (33 of 160 [22.8%] vs 3 of 54 [5.6%]).
A total of 250 COVID-19 patients (8.6%) were admitted to an ICU, compared with 169 flu patients (8.3%), but after adjustment, the rates were similar (sdHR, 1.08).
Analysis of a subgroup of patients hospitalized primarily for COVID-19 or flu found that the risk of death was 2.5 times higher, and the likelihood of ICU admission was 1.7 times higher, among Omicron than flu patients.
Patients with the SARS-CoV-2 Omicron variant had a higher risk of in-hospital mortality than those with influenza.
"These findings suggest that, despite virus evolution and improved management strategies, patients with the SARS-CoV-2 Omicron variant had a higher risk of in-hospital mortality than those with influenza," the researchers wrote.