Many patients with atrial fibrillation receive aspirin therapy besides oral anticoagulants, but concomitant aspirin therapy may be associated with increased risk for bleeding, according to an analysis of data from the ORBIT-AF registry.
“To date, there have been limited data available to define current patterns of use of concomitant antiplatelet therapy along with [oral anticoagulants] in AF patients in the United States,” researchers wrote in Circulation. “Furthermore, the risks of such combinations in community practice remain poorly defined.”
To address this question, researchers evaluated 7,347 AF patients on oral anticoagulants from the 10,126 AF patients enrolled in the ORBIT-AF registry. Rates of 6-month bleeding, hospitalization, ischemic events and mortality served as primary outcomes.
Thirty-five percent of patients on oral anticoagulants received concomitant aspirin therapy, according to study data. Men (66% vs. 53%; P<.0001) and those with comorbid illness were more likely to receive concomitant aspirin therapy than oral anticoagulation alone. History of atherosclerotic disease was absent in 39% of these patients. However, 17% had Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) bleeding risk scores ≥5.
Results also indicated that patients on oral anticoagulants and concomitant aspirin therapy were more likely to experience bleeding (adjusted HR=1.53; 95% CI, 1.20-1.96) and hospitalizations due to bleeding (adjusted HR=1.52; 95% CI, 1.17-1.97) compared with those on oral anticoagulants alone.
Ischemic event rates were low in both groups.
“These and other data raise the possibility that a less is more strategy may be favorable among AF patients on [oral anticoagulants]. However, we believe adequately powered, prospective clinical studies of these regimens are warranted to definitely assess the benefit or harm of such strategies,” the researchers wrote. “In the interim, clinicians need to carefully weigh whether the potential benefits of adding [aspirin therapy] are worth the risk among patients with AF on [oral anticoagulants.”
Disclosure: The ORBIT-AF registry is sponsored by Janssen Scientific Affairs. See the full study for a list of researchers’ financial disclosures.