Female sex was inconsistently associated with stroke risk , whereas the evidence was inconclusive that either heart failure or coronary artery disease is independently predictive of stroke .
Conclusions : Four clinical features ( prior stroke/TIA , advancing age , hypertension , diabetes ) are consistent independent risk factors for stroke in atrial fibrillation patients .
Background : Absolute stroke rates vary widely among patients with nonvalvular atrial fibrillation .
To balance the benefits and risks of chronic antithrombotic prophylaxis , it is important to estimate the absolute risk of stroke for individual patients .
Stroke Prevention in Atrial Fibrillation Study: Final Results
Background Atrial fibrillation in the absence of rheumatic valvular disease is associated with a fivefold to sevenfold increased risk of ischemic stroke . Methods and Main Results . The Stroke Prevention in Atrial Fibrillation Study , a multicenter , r and omized trial , compared 325 mg/day aspirin ( double-blind ) or warfarin with placebo for prevention of ischemic stroke and systemic embolism ( primary events ) , and included 1,330 in patients and out patients with constant or intermittent atrial fibrillation . During a mean follow-up of 1.3 years , the rate of primary events in patients assigned to placebo was 6.3 % per year and was reduced by 42 % in those assigned to aspirin ( 3.6 % per year , p = 0.02 ; 95 % confidence interval , 9–63 % ) . In the subgroup of  warfarin-eligible patients ( most less than 76 years old ) , warfarin dose-adjusted to prolong prothrombin time to 1.3-fold to 1.8-fold that of control reduced the risk of primary events by 67 % ( warfarin versus placebo , 2.3 % versus 7.4 % per year , p = 0.01 ; 95 % confidence interval , 27–85 % ) . Primary events or death were reduced 58 % ( p = 0.01 ) by warfarin and 32 % ( p = 0.02 ) by aspirin . The risk of significant bleeding was 1.5 % , 1.4 % , and 1.6%o per year in patients assigned to warfarin , aspirin , and placebo , respectively . Conclusions Aspirin and warfarin are both effective in reducing ischemic stroke and systemic embolism in patients with atrial fibrillation . Because warfarin-eligible patients composed a subset of all aspirin-eligible patients , the magnitude of reduction in events by warfarin versus aspirin can not be compared . Too few events occurred in warfarin-eligible patients to directly assess the relative benefit of aspirin compared with warfarin , and the trial is continuing to address this issue . Patients with nonrheumatic atrial fibrillation who can safely take either aspirin or warfarin should receive prophylactic antithrombotic therapy to reduce the risk of stroke
Female sex was inconsistently associated with stroke risk , whereas the evidence was inconclusive that either heart failure or coronary artery disease is independently predictive of stroke .
Conclusions : Four clinical features ( prior stroke/TIA , advancing age , hypertension , diabetes ) are consistent independent risk factors for stroke in atrial fibrillation patients .
Background : Absolute stroke rates vary widely among patients with nonvalvular atrial fibrillation .
To balance the benefits and risks of chronic antithrombotic prophylaxis , it is important to estimate the absolute risk of stroke for individual patients .