Background: Atrial fibrillation (AF) is the most common dysrhythmia among elderly patients. A co-morbidity associated with this disease process is embolic stroke. In an effort to reduce the potential morbidity and mortality associated with stroke, patients are often placed on the anticoagulant warfarin. While warfarin has been statistically proven to reduce the rate of embolic stroke in patients with AF, it potentiates increased risk of bleeding. The elderly population has an elevated level of AF and increased risk for fall and bleeding abnormalities. This systematic review aims to evaluate the risk versus benefit of prescribing warfarin in elderly patients with AF.
Methods: A comprehensive database search was completed, using Medline, CINAHL and EBMR Multifile. Inclusion criteria of English text, human trials, at least one study group with age > 70, atrial fibrillation, warfarin use vs. no anticoagulation therapy, morbidity, mortality and hemorrhage were determined prior to the search. In addition, exclusion criteria consisted of use of anticoagulation therapy following ablation therapy or other surgical forms of AF management, studies which included patients with mechanical heart valves or target INR >3 or study populations that were too narrowly drawn. Four articles were identified and evaluated in this study. Validity was noted based on eight factors.
Results: All four articles reviewed were observational studies, with no randomized controlled trials. In total, 14 342 patients were analyzed between 1996 and 2007, with study duration from six to 28 months. All studies took into account age and/or frailty in elderly patients with AF. Study groups varied from warfarin users to non-users, all warfarin users of varying age and frail vs. non-frail warfarin users, and non-users. With regard to general warfarin practices, two studies showed providers did not prescribe warfarin in the oldest and frailest patients, and two studies found no variation in INR measures with age. When considering advancing age, independent of warfarin therapy, two studies found a significant increase in stroke rate and one study found a significant increase in death rate with advancing age. Three studies evaluated hemorrhage risk in relation to increasing age independent of warfarin use, with one study finding a significant increase, one finding a non-significant increase and one finding no difference. When evaluating the use of warfarin, one study displayed no significant variation and one found a non-significant increase in hemorrhage rates for warfarin users with advancing age. One study found a non-significant increase in hemorrhage with supratherapeutic warfarin use.
Conclusion: Throughout this systematic review, warfarin therapy does not prove to be more harmful than no therapy, in elderly or frail patients with atrial fibrillation. Elderly and frail individuals are at a greater risk for stroke, death and potentially hemorrhage independent of anticoagulant use. Additional research is necessary in order to develop prescribing guidelines for warfarin therapy with consideration of age and frailty. It is imperative that warfarin be prescribed and monitored carefully in all age ranges, in order to provide the most effective prevention of embolic stroke while minimizing the risk of hemorrhage.
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