There are limited data on the impact of anemia on clinical outcomes in unstable angina and non-ST-segment elevation myocardial infarction treated with an early invasive strategy. We sought to determine the short- and long-term clinical events among patients with and without anemia enrolled in the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. Anemia was defined as baseline hemoglobin of <13 g/dl for men and <12 g/dl for women. The primary end points were composite ischemia (death, myocardial infarction, or unplanned revascularization for ischemia) and major bleeding assessed in-hospital, at 1 month, and at 1 year. Among the 13,819 patients in the ACUITY trial, information regarding anemia was available in 13,032 (94.3%), 2,199 of whom (16.9%) had anemia. Patients with anemia compared with those without anemia had significantly increased adverse event rates in-hospital (composite ischemia 6.6% vs 4.8%, p = 0.0004; major bleeding 7.3% vs 3.3%, p <0.0001), at 1 month (composite ischemia 10% vs 7.2%, p <0.0001, major bleeding 8.8% vs 3.9%, p <0.0001), and 1 year (composite ischemia 21.7% vs 15.3%, p <0.0001). Anemia was an independent predictor of death at 1 year (hazard ratio 1.77, 95% confidence interval [CI] 1.29 to 2.44, p = 0.0005). Composite ischemia was significantly more common among patients who developed in-hospital non-coronary artery bypass surgery major bleeding compared with those who did not (anemic patients 1-year relative risk 2.19, 95% CI 1.67 to 2.88, p <0.0001; nonanemic patients relative risk 2.16, 95% CI 1.76 to 2.65, p <0.0001). In conclusion, in the ACUITY trial, baseline anemia was strongly associated with adverse early and late clinical events, especially in those who developed major bleeding.
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