Impact of Anemia on Cardiovascular Outcomes in Patients with Acute Myocardial Infarction: Insights from the J-MINUET Study

Although anemia is associated with adverse outcomes after acute myocardial infarction (MI), the specific impact of anemia on individual components of the cardiovascular events remains inadequately clarified. This study consisted of 3,229 patients with acute MI from the J-MINUET study. There were 930 patients (28.8%) with anemia, defined as hemoglobin (Hb) levels < 12 g/dL in women and < 13 g/dL in men: 533 (16.5%) with mild anemia (Hb levels 11-12/13 g/dL) and 397 patients (12.3%) with moderate to severe anemia (Hb levels < 11 g/dL). Composite outcomes included all-cause death, admission for heart failure (HF), stroke, and recurrent MI. At 3-year follow-up, the incidence of the composite outcomes was 17.9% in patients with no anemia, 32.3% in those with mild anemia (hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.60-2.38, P < 0.001), and 56.1% in those with moderate to severe anemia (HR 3.91, 95%CI 3.26-4.69, P < 0.001). The impact of anemia was greatest for death, followed by admission for HF and stroke. This effect was more pronounced in patients with moderate to severe anemia. The influence of anemia on recurrent MI was less significant. While chronic kidney disease (CKD) amplified the adverse outcomes of anemia, the impact of anemia and its severity on the incidence of cardiovascular events was consistent regardless of CKD status. In conclusion, the most profound effect of anemia was observed for death, followed by HF and stroke in patients with MI, particularly in moderate to severe anemia, while the association with recurrent MI was less pronounced.