Impact of Anemia on Clinical Outcomes of Patients With ST-Segment Elevation Myocardial Infarction in Relation to Gender and Adjunctive Antithrombotic Therapy (from the HORIZONS-AMI Trial)

The aim of this study was to assess the impact of baseline anemia on the outcomes of patients with ST elevation myocardial infarctions who underwent primary percutaneous coronary intervention in relation to contemporary adjunctive antithrombotic therapy and gender. In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, patients were randomized to bivalirudin alone or to unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor before primary percutaneous coronary intervention. Outcomes were assessed at 30 days and 1 year according to anemia and gender. Baseline anemia was present in 331 of 3,153 patients (10.5%). Patients with versus without baseline anemia had a more than twofold increase in major bleeding at 30 days (13.5% vs 6.7%, p <0.0001) and at 1 year (14.8% vs 7.2%, p <0.0001), an association that on multivariate analysis was independent of gender. Mortality was significantly higher in men with versus without baseline anemia (4.6% vs 1.8% at 30 days, p = 0.003; 8.9% vs 3.0% at 1 year, p <0.0001) but not in women (5.3% vs 3.6% at 30 days, p = 0.42; 7.5% vs 5.9% at 1 year, p = 0.54). On multivariate analysis, anemia independently predicted 1-year all-cause mortality in men but not in women. Bivalirudin compared with unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor resulted in twofold lower rates of all-cause and cardiac mortality and major bleeding in patients without but not in those with baseline anemia. In conclusion, baseline anemia was associated with increased major bleeding and death in patients with ST elevation myocardial infarctions who underwent primary PCI but was a stronger predictor of early and late mortality in men than in women. Paradoxically, in this post hoc analysis, the reductions in major bleeding and mortality in ST elevation myocardial infarction afforded by bivalirudin occurred primarily in patients without baseline anemia.