Impact of anemia as risk factor for major bleeding and mortality in patients with acute coronary syndrome.

Background: Anemia is frequent in acute coronary syndrome (ACS) patients and is associated with worse clinical outcomes. We aimed to investigate the therapeutic strategies, the use of novel P2Y inhibitors, and the prognostic implication of anemia in a "real world" cohort of ACS patients.

Methods: This is an observational and prospective registry including 1717 ACS patients from three tertiary hospitals. During hospitalization we recorded the clinical management and the antiplatelet therapy at discharge. Patients were divided into 2 groups according to the baseline hemoglobin level, i.e. anemic (hemoglobin < 13 g/dL in men and <12 g/dL in women) and non-anemic patients. Bleeding events, mortality and major adverse cardiovascular events (MACEs) were recorded during 1-year of follow-up.

Results: Anemia was present in 445 (25.9%) patients. Cardiac catheterization (83.8% vs. 94.5%, p < .001), and revascularization by percutaneous coronary intervention (53.5% vs. 70.5%, p < .001) were less frequent in these patients. Excluding anticoagulated patients, novel P2Y inhibitors were less prescribed in anemic patients (OR 2.80 [95% CI 2.13-3.67], p < .001). Anemia was independently associated with major bleeding (HR 2.26 [95% CI 1.07-4.78], p = .033) and all-cause mortality (HR 1.62 [95% CI 1.03-2.56], p = .038), but not with MACE. At 1-year of follow-up, the risk of mortality in anemic patients taking clopidogrel was higher (HR 2.38 [95% CI 1.01-5.67]; p = .049).

Conclusions: In this registry involving ACS patients, anemia had influence on clinical management and antiplatelet therapy. Patients suffering from anemia had higher risk for major bleeding and mortality. In particular, anemic patients treated with clopidogrel had even more mortality events.