State-of-the-Art Paper
Age as a Risk Factor for Stroke in Atrial Fibrillation Patients: Implications for Thromboprophylaxis

https://doi.org/10.1016/j.jacc.2010.05.028Get rights and content
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The prevalence of atrial fibrillation (AF) is related to age and is projected to rise exponentially as the population ages and the prevalence of cardiovascular risk factors increases. The risk of ischemic stroke is significantly increased in AF patients, and there is evidence of a graded increased risk of stroke associated with advancing age. Oral anticoagulation (OAC) is far more effective than antiplatelet agents at reducing stroke risk in patients with AF. Therefore, increasing numbers of elderly patients are candidates for, and could benefit from, the use of anticoagulants. However, elderly people with AF are less likely to receive OAC therapy. This is mainly due to concerns about a higher risk of OAC-associated hemorrhage in the elderly population. Until recently, older patients were under-represented in randomized controlled trials of OAC versus placebo or antiplatelet therapy, and therefore the evidence base for the value of OAC in the elderly population was not known. However, analyses of the available trial data indicate that the expected net clinical benefit of warfarin therapy is highest among patients with the highest untreated risk for stroke, which includes the oldest age category. An important caveat with warfarin treatment is maintenance of a therapeutic international normalized ratio, regardless of the age of the patient, where time in therapeutic range should be ≥65%. Therefore, age alone should not prevent prescription of OAC in elderly patients, given an appropriate stroke and bleeding risk stratification.

Key Words

atrial fibrillation
bleeding risk
elderly
net clinical benefit
stroke risk
warfarin

Abbreviations and Acronyms

AF
atrial fibrillation
CI
confidence interval
HR
hazard ratio
ICH
intracranial hemorrhage
INR
international normalized ratio
OAC
oral anticoagulation
RCT
randomized controlled trial
RR
relative risk
TIA
transient ischemic attack
TTR
time in therapeutic range

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Prof. Lip has served as a consultant for Bayer, Astellas, Merck, AstraZeneca, Sanofi, Aryx, Portola, Biotronic, and Boehringer, and has been on the Speakers' Bureau for Bayer, Boehringer, and Sanofi. Dr. Lane is in receipt of an investigator-initiated educational grant from Bayer Healthcare, and has received industry-funded sponsorship for travel to cardiology conferences. All other authors have reported that they do not have any relationships to disclose.