BackgroundAnemia may predispose to thromboembolic events or bleeding in anticoagulated patients with atrial fibrillation (AF).
ObjectivesTo investigate whether anemia is associated with thromboembolic events and bleeding in patients with AF.
Patients and methodsWe retrospectively analyzed the RE-LY trial database, which randomized 18113 patients with AF and a risk of stroke to receive dabigatran or warfarin for a median follow-up of 2years. Cox regression analysis was used to determine whether anemia predicted cardiovascular events and bleeding complications in these patients.
ResultsAnemia was present in 12% of the population at baseline, and the presence of anemia was associated with a higher risk of thromboembolic cardiovascular events, including the composite endpoint of all-cause mortality or myocardial infarction (adjusted hazard ratio [HR]1.50, 95% confidence interval [CI]1.32-1.71) and the primary RE-LY outcome of stroke or systemic embolism (adjusted HR1.41, 95%CI1.12-1.78). Anemia was also associated with a higher risk of major bleeding complications (adjusted HR2.14, 95%CI1.87-2.46) and discontinuation of anticoagulants (adjusted HR1.40, 95%CI1.28-1.79). The association between anemia and outcome was similar irrespective of cardiovascular comorbidities, randomized treatment allocation, or prior use of warfarin. The incidence of events was lower in patients with transient anemia than in patients in whom anemia was sustained (adjusted HR0.66, 95%CI0.49-0.91).
ConclusionsAnemia is associated with an increased risk of thromboembolic events, bleeding complications and mortality in anticoagulated patients with AF. These findings suggest that patients with anemia should be monitored closely during all types of anticoagulant treatment.