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. 2023 Sep 27;18(9):e0292017.
doi: 10.1371/journal.pone.0292017. eCollection 2023.

Higher in-hospital mortality in SARS-CoV-2 omicron variant infection compared to influenza infection-Insights from the CORONA Germany study

Jannis Dickow  1 , Melanie A Gunawardene  1 , Stephan Willems  1   2 , Johannes Feldhege  3 , Peter Wohlmuth  2   3 , Martin Bachmann  4 , Martin W Bergmann  5   6 , Wolfgang Gesierich  7 , Lorenz Nowak  8 , Ulrich-Frank Pape  9 , Ruediger Schreiber  10 , Sebastian Wirtz  11 , Raphael Twerenbold  12 , Sara Sheikhzadeh  2   3   13 , Nele Gessler  1   2   3
Affiliations

Higher in-hospital mortality in SARS-CoV-2 omicron variant infection compared to influenza infection-Insights from the CORONA Germany study

Jannis Dickow et al. PLoS One. .

Abstract

Background: With the emergence of new subvariants, the disease severity of Severe Acute Respiratory Syndrome Coronavirus-2 has attenuated. This study aimed to compare the disease severity in patients hospitalized with omicron variant infection to those with influenza infection.

Methods: We compared data from the multicenter observational, prospective, epidemiological "CORONA Germany" (Clinical Outcome and Risk in hospitalized COVID-19 patients) study on patients infected with Severe Acute Respiratory Syndrome Coronavirus-2 to retrospective data on influenza infection cases from November 2016 to August 2022. Severe Acute Respiratory Syndrome Coronavirus-2 cases were classified as wild-type/delta variant before January 2022, or omicron variant from January 2022 onward. The primary outcome was in-hospital mortality, adjusted for age, gender, and comorbidities.

Results: The study included 35,806 patients from 53 hospitals in Germany, including 4,916 patients (13.7%) with influenza infection, 16,654 patients (46.5%) with wild-type/delta variant infection, and 14,236 patients (39.8%) with omicron variant infection. In-hospital mortality was highest in patients with wild-type/delta variant infection (16.8%), followed by patients with omicron variant infection (8.4%) and patients with influenza infection (4.7%). In the adjusted analysis, higher age was the strongest predictor for in-hospital mortality (age 80 years vs. age 50 years: OR 4.25, 95% CI 3.10-5.83). Both, patients with wild-type/delta variant infection (OR 3.54, 95% CI 3.02-4.15) and patients with omicron variant infection (OR 1.56, 95% CI 1.32-1.84) had a higher risk for in-hospital mortality than patients with influenza infection.

Conclusion: After adjusting for age, gender and comorbidities, patients with wild-type/delta variant infection had the highest risk for in-hospital mortality compared to patients with influenza infection. Even for patients with omicron variant infection, the adjusted risk for in-hospital mortality was higher than for patients with influenza infection. The adjusted risk for in-hospital mortality showed a strong age dependency across all virus types and variants.

Trial registration number: NCT04659187.

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Conflict of interest statement

NG reports grants from Boston Scientific, grants from Medtronic and support from Bayer Vital outside the submitted work. MAG reports grants/speaker honoraria and consultation fees from Boston Scientific, Farapulse Inc., Biosense Webster, Abbott and Medtronic outside the submitted work. WG reports grants/speaker honoraria and consultation fees from AstraZeneca, Olympus and PulmonX outside the submitted work. This does not alter our adherence to PLOS ONE policies on sharing data and materials. All other authors have nothing to disclose.

Figures

Fig 1
Fig 1. Forest plot of model effects.
When adjusted for age, gender, and comorbidities, age, liver cirrhosis/fibrosis and tumor disease had a strong impact on in-hospital mortality. Among virus groups, patients with wild-type to delta variant infection had a higher risk for in-hospital mortality compared to patients with influenza infection. Furthermore, patients with omicron variant infection had a higher risk for in-hospital mortality when compared to patients with influenza infection. COPD indicates chronic obstructive pulmonary disease.
Fig 2
Fig 2. Model-based probabilities of mortality by virus type and variant.
Wild-type to delta infection increased the risk for in-hospital mortality compared to influenza infection or omicron variant infection. Infection with the omicron variant was also associated with higher mortality, but the difference to influenza infection remains moderate.
See this image and copyright information in PMC

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