Impact of Hemoglobin Levels on Composite Cardiac Arrest or Stroke Outcome in Patients With Respiratory Failure Due to COVID-19
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Shi Nan Feng1, Thu-Lan Kelly2, John F Fraser3,4
1Division of Neuroscience Critical Care, Departments of Neurology, Neurosurgery, and Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
Insights
Moderate to severe anemia in COVID-19 patients admitted to the intensive care unit (ICU) is linked to a higher risk of cardiac arrest or stroke. This finding highlights the importance of monitoring hemoglobin levels in critically ill COVID-19 patients.
Area of Science:
- Critical Care Medicine
- Hematology
- Infectious Diseases
Background:
- Anemia is a known risk factor for adverse cardiovascular events.
- COVID-19 is frequently associated with cardiac complications, including cardiac arrest and stroke.
- The relationship between hemoglobin levels and these complications in COVID-19 patients requires further investigation.
Purpose of the Study:
- To investigate the association between hemoglobin levels at ICU admission and the composite outcome of cardiac arrest or stroke in an international cohort of COVID-19 patients.
- To determine if anemia severity influences the risk of cardiac arrest or stroke in critically ill COVID-19 patients.
Main Methods:
- Retrospective analysis of a prospectively collected international registry database of COVID-19 patients admitted to ICUs.
- Anemia was categorized based on hemoglobin levels: normal, mild, moderate, and severe.
- Cox proportional hazards regression was used to analyze the time to stroke or cardiac arrest, with death as a competing risk, adjusting for relevant covariates.
Main Results:
- Of 6926 COVID-19 ICU patients, 11.0% experienced stroke and/or cardiac arrest.
- The incidence of cardiac arrest or stroke was higher in patients with lower hemoglobin levels.
- Moderate/severe anemia was significantly associated with an increased hazard of cardiac arrest or stroke (Hazard Ratio, 1.32; 95% CI, 1.05-1.67).
Conclusions:
- Moderate to severe anemia at ICU admission is associated with an increased risk of cardiac arrest or stroke in COVID-19 patients.
- These findings underscore the clinical significance of anemia in predicting adverse outcomes in critically ill COVID-19 patients.
Objectives:
Anemia has been associated with an increased risk of both cardiac arrest and stroke, frequent complications of COVID-19. The effect of hemoglobin level at ICU admission on a composite outcome of cardiac arrest or stroke in an international cohort of COVID-19 patients was investigated.
Design:
Retrospective analysis of prospectively collected database.
Setting:
A registry of COVID-19 patients admitted to ICUs at over 370 international sites was reviewed for patients diagnosed with cardiac arrest or stroke up to 30 days after ICU admission. Anemia was defined as: normal (hemoglobin ≥ 12.0 g/dL for women, ≥ 13.5 g/dL for men), mild (hemoglobin 10.0-11.9 g/dL for women, 10.0-13.4 g/dL for men), moderate (hemoglobin ≥ 8.0 and < 10.0 g/dL for women and men), and severe (hemoglobin < 8.0 g/dL for women and men).
Patients:
Patients older than 18 years with acute COVID-19 infection in the ICU.
Interventions:
None.
Measurements And Main Results:
Of 6926 patients (median age = 59 yr, male = 65%), 760 patients (11.0%) experienced stroke (2.0%) and/or cardiac arrest (9.4%). Cardiac arrest or stroke was more common in patients with low hemoglobin, occurring in 12.8% of patients with normal hemoglobin, 13.3% of patients with mild anemia, and 16.7% of patients with moderate/severe anemia. Time to stroke or cardiac arrest by anemia status was analyzed using Cox proportional hazards regression with death as a competing risk. Covariates selected through clinical knowledge were age, sex, comorbidities (diabetes, hypertension, obesity, and cardiac or neurologic conditions), pandemic era, country income, mechanical ventilation, and extracorporeal membrane oxygenation. Moderate/severe anemia was associated with a higher risk of cardiac arrest or stroke (hazard ratio, 1.32; 95% CI, 1.05-1.67).
Conclusions:
In an international registry of ICU patients with COVID-19, moderate/severe anemia was associated with increased hazard of cardiac arrest or stroke.
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