Objectives: To determine the influence of advanced age on anticoagulant use in subjects with atrial fibrillation and to explore the extent to which risk factors for stroke and contraindications to anticoagulant therapy predict subsequent use.
Design: Retrospective cohort study.
Setting: The Veterans Affairs Boston Healthcare System.
Participants: A total of 2,217 subjects with nonvalvular atrial fibrillation.
Measurements: Administrative databases were use to identify subject's age, anticoagulant use, and the presence of a diagnosis of atrial fibrillation, cerebrovascular accident, hypertension, diabetes mellitus, congestive heart failure, or gastrointestinal or cerebral hemorrhage.
Results: Unadjusted analysis showed no difference in warfarin use between those aged 75 and older and younger subjects regardless of the presence (33.9% vs 35.7%, P=.37) or absence (33.4% vs 34.7%, P=.58) of contraindications to anticoagulant therapy. Multivariate modeling demonstrated a 14% reduction (95% confidence interval (CI)=4-22%) in anticoagulant use with each advancing decade of life. Intracranial hemorrhage was a significant deterrent (odds ratio (OR)=0.27 95% CI=0.06-0.85). History of hypertension (OR=2.90, 95% CI=2.15-3.89), congestive heart failure (OR=1.70, 95% CI=1.41-2.04), and cerebrovascular accident (OR=1.54, 95% CI=1.25-1.89) were significant independent predictors for anticoagulant use.
Conclusion: Despite consensus guidelines to treat all atrial fibrillation patients aged 75 and older with anticoagulants, advancing age was found to be a deterrent to warfarin use. Better estimates of the risk:benefit ratio for oral anticoagulant therapy in older patients with atrial fibrillation are needed to optimize decision-making.