Study Finds High Risks of Warfarin Use in Older AF Patients
October 13th, 2016
NEW YORK – For physicians already hesitant to prescribe oral anticoagulants to older adults with atrial fibrillation (AF), here’s some bad news: The risks might be worse than you suspected.
A study in JAMA Cardiology points out that older age is a significant risk factor for thromboembolic stroke in patients with AF, and that drug therapy with warfarin reduces the threat by almost two-thirds in patients at high risk. At the same time, however, traumatic intracranial bleeding, usually caused by a fall, is a great concern.
The study, led by New York University School of Medicine researchers, looked at 31,951 U.S. veterans with AF, 75 years or older, who were new referrals to Veterans Affairs (VA) anticoagulation clinics between 2002 and 2012.
The rate of traumatic intracranial bleeding among older adults with AF initiating warfarin therapy actually was higher than previously reported in clinical trials. Among the factors putting patients at increased risk of traumatic intracranial bleeding were dementia, anemia, depression, anticonvulsant use, and labile international normalized ratio (INR).
With a mean patient age of 81.1 in the almost all-male study group, the incidence rate of hospitalization for traumatic intracranial bleeding was 4.80 per 1000 person-years, according to the results. The incidence rates of hospitalization for any intracranial bleeding and ischemic stroke were 14.58 and 13.44, respectively.
Comorbidities were common, including hypertension (82.5%), coronary artery disease (42.6%), and diabetes mellitus (33.8%).
“Among patients 75 years or older with atrial fibrillation initiating warfarin therapy, the risk factors for traumatic intracranial bleeding are unique from those for ischemic stroke,” the study concluded. “The high overall rate of intracranial bleeding in our sample supports the need to more systematically evaluate the benefits and harms of warfarin therapy in older adults.”
Authors note that they were unable to generate a clinical prevention tool to evaluate risk but “still believe that the individual factors we identified may potentially be used in patient-centered discussions about the benefits and harms of warfarin therapy in older adults.” They also call for validation in other data sets, including more women.