Impact of Hemoglobin Levels on Composite Cardiac Arrest or Stroke Outcome in Patients With Respiratory Failure Due to COVID-19

Crit Care Explor. 2024 Aug 22;6(9):e1143. doi: 10.1097/CCE.0000000000001143. eCollection 2024 Sep 1.

Abstract

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.

MeSH terms

  • Adult
  • Aged
  • Anemia* / blood
  • Anemia* / epidemiology
  • COVID-19* / blood
  • COVID-19* / complications
  • COVID-19* / epidemiology
  • Female
  • Heart Arrest* / epidemiology
  • Heart Arrest* / etiology
  • Hemoglobins* / analysis
  • Hemoglobins* / metabolism
  • Humans
  • Intensive Care Units
  • Male
  • Middle Aged
  • Registries
  • Respiratory Insufficiency* / epidemiology
  • Respiratory Insufficiency* / etiology
  • Retrospective Studies
  • Risk Factors
  • SARS-CoV-2
  • Stroke* / blood
  • Stroke* / epidemiology

Substances

  • Hemoglobins