Iron Deficiency in Acute Coronary Syndromes—Clinical Correlates and Outcomes

Background: Iron deficiency is common in heart failure and relates to a worse prognosis, but its role in acute coronary syndromes is unclear. This study assessed iron deficiency prevalence, correlation with infarct size and left ventricular function, and association with in-hospital and post-discharge events in such patients. Methods: We analyzed 152 acute coronary syndrome patients using multiple iron deficiency definitions: serum iron <6 µmol/L or <13 µmol/L; transferrin saturation (TSAT) <20%; ferritin <100 µg/L; and a combined definition – ferritin <100 µg/L or TSAT<20% if ferritin 100-299 µg/L. Infarct size was approximated by peak cardiac troponin T. Cox regression analysis examined associations with in-hospital complications (death, sustained arrhythmias, or Killip class ≥3) and post-discharge events (death, myocardial infarction, or stroke). Results: The prevalence of iron deficiency ranged from 21% to 62%, depending on definitions. Patients with deficiency defined by serum iron or TSAT were older, more frequently female, with more cardiovascular risk factors, and higher high-sensitivity C-reactive protein. Serum iron <13 µmol/L and TSAT <20% correlated with lower left ventricular ejection fraction but not with greater infarct size. Iron deficiency did not predict in-hospital complications, whereas serum iron <6 µmol/L was associated with a higher risk of post-discharge events. Such association lost significance after adjustment for hs-CRP. Lower ferritin predicted fewer events. Conclusion: Iron deficiency is frequent in acute coronary syndromes. Definitions by serum iron and TSAT identify patients with worse left ventricular systolic function and more inflammation, potentially influencing prognosis.