Key result
Continuing warfarin in AF patients with dementia is linked to ~26% lower ischemic stroke risk.
Why the study?
Does continued use of warfarin prevent ischemic stroke and mortality in older adults with nonvalvular atrial fibrillation newly diagnosed with dementia?
Cohort (n=2,572)
Yes
Does continued use of warfarin prevent ischemic stroke and mortality in older adults with nonvalvular atrial fibrillation newly diagnosed with dementia?
Effect estimate: HR 0.74 (95% CI 0.54-0.996)
p-value: p=0.047
Continuing warfarin therapy in older adults with atrial fibrillation after a new diagnosis of dementia is associated with reduced risks of ischemic stroke and mortality without significantly increasing major bleeding.
May support individualized warfarin continuation in AF with new dementia; leaves open need for RCTs to confirm net benefit.
OBJECTIVES: To determine the effectiveness of warfarin in older adults with dementia. DESIGN: Retrospective cohort study. SETTING: Department of Veterans Affairs national healthcare system. PARTICIPANTS: Veterans aged 65 and older (73% aged ≥75, 99% male, 91% white) who had been receiving warfarin for nonvalvular atrial fibrillation for at least 6 months, were newly diagnosed with dementia in fiscal year 2007 or 2008, and were not enrolled in Medicare Advantage (n = 2,572). MEASUREMENTS: The onset of dementia was defined according to International Classification of Diseases, Ninth Revision, code. Participants were followed for up to 4 years for persistence of warfarin therapy, anticoagulation control, major hemorrhage, ischemic stroke, and all-cause mortality. RESULTS: The average CHADS2 score was 3.3 ± 1.3. After a diagnosis of dementia, 405 individuals (16%) persisted on warfarin therapy. Unadjusted Cox proportional hazards analysis demonstrated a protective effect of warfarin in prevention of ischemic stroke (hazard ratio (HR) = 0.64, 95% confidence interval (CI) = 0.46-0.89, P = .008), major bleeding (HR = 0.72, 95% CI = 0.55-0.94, P = .02), and all-cause mortality (HR = 0.66, 95% CI = 0.55-0.79, P < .001). Using propensity score matching, the protective effect of continuing warfarin persisted in prevention of stroke (HR = 0.74, 95% CI = 0.54-0.996, P = .047) and mortality (HR = 0.72, 95% CI = 0.60-0.87, P < .001), with no statistically significant decrease in risk of major bleeding (HR = 0.78, 95% CI = 0.61-1.01, P = .06). CONCLUSION: Discontinuing warfarin after a diagnosis of dementia is associated with a significant increase in stroke and mortality.
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Orkaby et al. (2016) conducted a cohort in Atrial fibrillation and dementia (n=2,572). Warfarin continuation vs. Warfarin discontinuation was evaluated on Ischemic stroke (HR 0.74, 95% CI 0.54-0.996, p=0.047). Continuing warfarin after a dementia diagnosis in older adults with atrial fibrillation was associated with a reduced risk of ischemic stroke (HR 0.74; 95% CI 0.54-0.996; P=0.047) and mortality.
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