Elsevier

American Heart Journal

Volume 161, Issue 2, February 2011, Pages 241-246
American Heart Journal

Curriculum in Cardiology
Atrial fibrillation, anticoagulation, fall risk, and outcomes in elderly patients

https://doi.org/10.1016/j.ahj.2010.11.002Get rights and content

Atrial fibrillation (AF) affects 2.5 million patients in the United States. The incidence of this condition increases with age, such that approximately 5% of people >65 years of age have AF. Because of the lack of organized atrial contraction and thrombus formation in the left atrium, patients with AF are at increased risk of stroke. The estimated risk of stroke among all AF patients is 5% per year. Among patients without mitral stenosis, there is a graded relationship of stroke risk with the number of CHADS2 risk factors. Warfarin is the recommended treatment for embolic stroke prophylaxis in AF in intermediate- to high-risk patients. However, elderly patients who are deemed to be at risk of falls are often not started on warfarin therapy secondary to a perceived higher risk of bleeding complications. These risks have been evaluated, but conclusive data regarding the risk-benefit trade-off are elusive. This review summarizes available data on the use of warfarin in elderly patients with AF, focusing on the risk of bleeding, and will specifically address the utility of falls risk assessment in the decision to initiate warfarin therapy for AF.

Section snippets

Stroke prevention

Multiple clinical trials and subsequent meta-analyses have demonstrated the benefit of aspirin compared with placebo, as well as warfarin compared with placebo, in reducing stroke risk among AF patients (Table I). In a pooled analysis of 3 randomized controlled trials (RCTs), the Atrial Fibrillation Investigators found that the relative risk reduction for aspirin versus placebo was 21% (95% CI 0%-38%, P = .05).12 In addition, another meta-analysis of 6 RCTs of aspirin versus placebo for stroke

Hemorrhagic complications

The relative benefit of warfarin compared with aspirin in preventing embolic stroke is known12, 13; however, warfarin therapy is not without risk. The association of hemorrhagic complications with warfarin use is well established, and elderly patients appear to be at higher risk.9, 16 In one analysis, when compared with patients <50 years of age, the unadjusted relative risk of patients ≥80 years of age having a life-threatening or fatal bleed on warfarin was 4.5 (95% CI 1.3-15.6); after

Warfarin monotherapy

Recommendations for anticoagulation therapy in AF patients should consider the balance of stroke risk, bleeding risk, and other complications of warfarin therapy, all of which appear to be at least in part associated with the intensity of anticoagulation. Prothrombin time ratio is a strong predictor of bleeding risk in all age groups.18 In addition, international normalized ratio (INR) may be associated with worse stroke outcomes. For example, in one study of AF patients taking warfarin who

Anticoagulation and risk of falls

Although increasing age is consistently associated with increased bleeding risk in warfarin therapy, an evaluation that specifically focused on fall-related hemorrhagic events showed that warfarin treatment was not associated with an increased risk of bleeding complications. In this study, the cohort treated with warfarin (379 falls patients) exhibited a hemorrhagic event rate of 6%, compared with 11% among patients (2,256 falls) not treated with warfarin (P = .01).26 However, these results

Future directions

The ACTIVE trials explored the role of clopidogrel (an irreversible inhibitor of the platelet P2Y12 receptor) plus aspirin versus aspirin alone in warfarin-intolerant patients (ACTIVE A) and clopidogrel plus aspirin versus warfarin (ACTIVE W) in AF patients who were able to take warfarin.27 These trials included patients with AF at enrollment or ≥2 episodes of AF in the previous 6 months, in addition to ≥1 of the following risk factors for stroke: age >74 years, hypertension, previous stroke or

Conclusions

The population of elderly patients with AF presents challenges with regard to the decision to provide anticoagulation treatment as well as which therapy, aspirin or warfarin, to choose. A higher likelihood of drug-drug interactions with warfarin, more adverse effects, and more comorbidities are at play in making these decisions. However, the available data suggest that physicians' decisions are guided more by their concerns over bleeding than an evaluation of the patient's risk for stroke; in

References (36)

  • LinH.J. et al.

    Stroke severity in atrial fibrillation. The Framingham Study

    Stroke

    (1996)
  • Man-Son-HingM. et al.

    Anticoagulant-related bleeding in older persons with atrial fibrillation: physicians' fears often unfounded

    Arch Intern Med

    (2003)
  • HeJ. et al.

    Aspirin and risk of hemorrhagic stroke: a meta-analysis of randomized controlled trials

    JAMA

    (1998)
  • RosandJ. et al.

    The effect of warfarin and intensity of anticoagulation on outcome of intracerebral hemorrhage

    Arch Intern Med

    (2004)
  • Man-Son-HingM. et al.

    Choosing antithrombotic therapy for elderly patients with atrial fibrillation who are at risk for falls

    Arch Intern Med

    (1999)
  • The efficacy of aspirin in patients with atrial fibrillation. Analysis of pooled data from 3 randomized trials. The Atrial Fibrillation Investigators

    Arch Intern Med

    (1997)
  • HartR.G. et al.

    Antithrombotic therapy to prevent stroke in patients with atrial fibrillation: a meta-analysis

    Ann Intern Med

    (1999)
  • FusterV. et al.

    ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society

    Circulation

    (2006)
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    George J. Klein, MD served as guest editor for this article.

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