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Comparative analysis of COVID-19 critically ill patients across four pandemic waves in Greece
Stelios Kokkoris1, Aikaterini Goufa2, Dimitrios Tsilivarakis1
1National and Kapodistrian University of Athens, Medical School, First Department of Critical Care Medicine, Evangelismos Hospital, Athens, Greece.
Insights
The impact of COVID-19 waves and virus variants on intensive care unit (ICU) mortality appears minimal. Focus should shift to patient factors like age and comorbidities for predicting outcomes in Coronavirus Disease-2019 patients.
Area of Science:
- Critical Care Medicine
- Infectious Diseases
- Epidemiology
Background:
- Limited data exists on intensive care unit (ICU) mortality trends for Coronavirus Disease-2019 (COVID-19) patients across the entire pandemic.
- Understanding these trends is crucial for managing future outbreaks and optimizing critical care strategies.
Purpose of the Study:
- To compare ICU mortality rates among four distinct pandemic waves, correlating with predominant SARS-CoV-2 variants.
- To identify factors influencing ICU mortality in COVID-19 patients throughout the pandemic.
Main Methods:
- A retrospective analysis of prospectively collected data from 805 adult COVID-19 patients admitted to the ICU between March 2020 and April 2022.
- Kaplan-Meier and Cox proportional hazards analyses were employed to assess ICU mortality across pandemic waves defined by variant predominance.
- Key patient demographics, comorbidities, and severity scores (APACHE II, Charlson, SOFA) were analyzed.
Main Results:
- Overall ICU mortality was 48%, with 54% hospital mortality. Invasive mechanical ventilation was required by 84% of patients.
- No significant differences in ICU mortality were observed among the four pandemic waves.
- Independent predictors of ICU mortality included age, malignancy, chronic pulmonary disease, and SOFA score; pandemic wave was not a significant predictor.
Conclusions:
- The influence of COVID-19 waves and associated SARS-CoV-2 variants on ICU mortality appears negligible.
- Patient-specific factors, particularly age and comorbidities, are more critical determinants of ICU mortality.
- These findings can inform future outbreak modeling and risk stratification strategies for critically ill COVID-19 patients.
Introduction:
There is limited information about trends in mortality of intensive care unit (ICU) patients with Coronavirus Disease-2019 (COVID-19) throughout the entire pandemic period.
Aim:
We compared the ICU mortality among the four consecutive waves of the pandemic, according to the virus variant predominance.
Methods:
This is a retrospective study of prospectively collected data extracted from our COVID-19 clinical database. All adult patients with confirmed SARS-CoV-2 infection, consecutively admitted to our ICU from March 2020 through April 2022, were included. For the analysis we used the dates of the four periods of the pandemic, according to the predominance of different SARS-CoV-2 variants in Greece. Kaplan-Meier and Cox proportional hazards analyses were used.
Results:
In total, 805 patients [median (IQR) age 67 (56-76) years, 68% males] were included. APACHE II, Charlson, and SOFA scores were 14 (11-19), 3 (2-5) and 7 (4-9), respectively; 674 (84%) patients required invasive mechanical ventilation. ICU length of stay was 15 (8-29) days, and mechanical ventilation duration was 11 (4-24) days. ICU and hospital mortality was 48% and 54%, respectively. Kaplan-Meier survival curves revealed no significant differences in ICU mortality among the four waves. Age, malignancy, chronic pulmonary disease and SOFA score were independent predictors of ICU mortality, but the pandemic waves themselves were not. Age had a significant impact on ICU mortality across all waves.
Conclusion:
The effect of COVID-19 wave (and consequently of the SARS- CoV-2 variant) on ICU mortality seems to be trivial, and therefore our focus should be shifted to other risk factors, such as age and comorbidities. These findings along with those of other studies could be useful for modelling the evolution of future outbreaks.
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