Fall risk and anticoagulation for atrial fibrillation in the elderly: A delicate balance

FALLS AND ANTICOAGULATION

Falls are an important source of morbidity, disability, and activity curtailment in older adults and, like atrial fibrillation, the incidence and prevalence of falls increase with age. In community-dwelling adults age 65 and older, the overall proportion with at least 1 fall in the preceding year ranges from about 30% to 40%.¹⁹ However, the rate increases with age and exceeds 50% in nursing home residents.²⁰

Although anticoagulation is associated with a higher risk of bleeding in patients who fall, the absolute risk is small.

In a study of older adults with nonvalvular atrial fibrillation, a history of falls or documented high risk of falling was associated with a risk of intracranial hemorrhage during follow-up that was 1.9 times higher.²¹ Importantly, however, this risk did not differ among patients treated with warfarin, aspirin, or no antithrombotic therapy. In this analysis, patients with a CHADS₂ score of 2 or higher benefited from anticoagulation, whether or not they were considered to be at risk for falls.

In another study,²² it was estimated that an individual would have to fall 295 times in 1 year for the risk of fall-related major bleeding to outweigh the benefit of warfarin in reducing the risk of stroke.

Thus, based on available evidence, perception of a high risk of falling should not be construed as justification for withholding anticoagulation in older patients who are otherwise suitable candidates for such therapy.

AT WHAT POINT DOES BLEEDING RISK OUTWEIGH ANTICOAGULATION BENEFIT?

Absolute contraindications to anticoagulation include an intracranial hemorrhage or neurosurgical procedure with high risk for bleeding within the past 30 days, an intracranial neoplasm or vascular abnormality with high risk of bleeding, recurrent life-threatening gastrointestinal or other bleeding events, and severe bleeding disorders, including severe thrombocytopenia.

In patients with atrial fibrillation at high risk of bleeding as assessed by one of the bleeding risk scores and relatively low risk of ischemic stroke, the risk of anticoagulation may outweigh the benefit, although no studies have specifically addressed this issue.

In patients with frequent falls, including injurious falls, the benefits of anticoagulation usually outweigh the risks of bleeding, but management should incorporate interventions designed to mitigate fall risk.

Finally, in patients with a poor prognosis approaching the end of life, the risks and burdens of anticoagulation may exceed the perceived benefits, in which case discontinuation of anticoagulation may be appropriate.

SHOULD OUR PATIENT RECEIVE ANTICOAGULATION?

As noted above, our patient has a high risk of stroke and a moderate risk of bleeding, and multiple lines of evidence indicate that the benefits of anticoagulation (ie, prevention of stroke and systemic embolization) substantially outweigh the risks of bleeding. Although she has a history of falls, which may seem to muddy the waters, this factor should not play a major role in decision-making. Moreover, her advanced age should, if anything, be considered a point in favor of anticoagulation. So from the scientific standpoint, anticoagulation is the clear winner.

A shared decision

But that is not the end of the story. Since there is tension between benefits and risks with either approach (ie, anticoagulation or no anticoagulation), it is important to discuss the issues and options with the patient and relevant caregivers. Most older adults have witnessed the ravages of stroke in a friend or relative, and a recent study showed that most would be willing to accept a modest risk of bleeding to prevent a stroke.²³

However, this is ultimately a personal decision for each patient, and in accordance with the principle of patient autonomy, the patient’s expressed wishes should be honored by using a process of shared decision-making.

Which anticoagulant?

Finally, what about the choice of anticoagulation? The complexities of using warfarin, including its narrow therapeutic range and myriad interactions with other medications and foods, can make it a less appealing option for both patient and provider.

We recommend a novel oral anticoagulant as first-line therapy in the absence of contraindications such as severe renal insufficiency, and prefer apixaban because it is the only agent shown to be superior to warfarin with respect to both stroke prevention and bleeding risk.²⁴

Important disadvantages of the novel oral anticoagulants include their higher cost and lack of an effective antidote in the event of clinically significant bleeding (with the exception of idarucizumab, which was recently approved for reversal of serious bleeding associated with dabigatran), issues that may be of particular concern to older adults. While there is no therapeutic range to monitor for the newer agents, more frequent monitoring for occult anemia may be needed.

Thus, selection of an anticoagulant should also be individualized through shared decision-making.

Is aspirin alone an alternative?

And what if the patient chooses to forgo anticoagulation? In that case, aspirin 75 to 325 mg/day may seem reasonable, but there is scant evidence that aspirin is beneficial for stroke prevention in patients with atrial fibrillation in this age group, and aspirin, too, is associated with an increased risk of bleeding.²⁵

As a result, current US and European guidelines recommend a very limited role for aspirin as a single agent in the management of atrial fibrillation.²⁶ The joint 2014 guidelines of the American Heart Association, American College of Cardiology, and Heart Rhythm Society give aspirin a class IIB recommendation (ie, it “may” be considered), level of evidence C (ie, very limited) for use as an alternative to no antithrombotic therapy or systemic anticoagulation only in patients with a CHA₂DS₂-VASc score of 1, thereby excluding all patients age 75 and older.¹³

In most cases, aspirin as sole prophylaxis against stroke in atrial fibrillation should be avoided in the absence of another indication for its use, such as coexisting coronary artery disease or peripheral arterial disease.

A COMPLEX DECISION

In summary, the decisions surrounding anticoagulation of elderly patients with nonvalvular atrial fibrillation are complex. Accurate assessment of stroke risk is key, and although bleeding risk is also an essential consideration, it is important not to overemphasize bleeding and fall risks in the decision-making process.