Relevance of pre-existing anaemia for patients admitted for acute coronary syndrome to an intensive care unit: a retrospective cohort analysis of 7418 patients

Abstract

Abstract Aims Patients with acute coronary syndrome (ACS) frequently suffer from anaemia, but its role in patients admitted to an intensive care unit (ICU) is unclear. This analysis evaluates the prognostic relevance of different degrees of anaemia and their specific impact on disease severity and the outcome in critically ill ACS patients. Methods and results and results The multi-centre electronic Intensive Care Unit Collaborative Research Database was used, and all patients admitted with ACS were included in a retrospective analysis. Anaemia and its degrees were defined according to the criteria by the World Health Organization. A multi-level logistic regression analysis was used to fit three sequential regression models for the binary primary outcome of hospital mortality. A total of 7418 patients were included; 3437 patients (46%) had anaemia on admission. Patients with anaemia were significantly older [61 (53–70) vs. 70 (61–78) years, P < 0.001], more often female (P < 0.001), and required an increased rate of vasopressor use (P < 0.001) and mechanical ventilation (P < 0.001). With the higher Sequential organ failure assessment score (1 vs. 2; P < 0.001) and Acute Physiology And Chronic Health Evaluation (35 vs. 47; P < 0.001) scores, a higher degree of anaemia was associated with prolonged ICU stay (2 vs. 5 days, P < 0.001). Even patients with mild anaemia needed significantly from more intensive treatment and suffered worse outcome. Intensive care unit and hospital mortality were inversely associated with haemoglobin levels. Conclusion Nearly half of critically ill patients with ACS suffer from anaemia, which is associated with increased illness severity, complex ICU procedures, and mortality—even in mild anaemia. Haemoglobin on admission is an independent factor for adverse outcome.