The various risk stratification schemes classified variable proportions as low , moderate and high risk , but the CHA(2)DS(2)-VASc score classified the smallest proportion of patients as ' low risk ' .
Anticoagulation with vitamin K antagonists and dabigatran is cost-effective in patients at high risk of stroke , but not in patients without any other stroke risk factor beside AF .
Effect of Age on Stroke Prevention Therapy in Patients With Atrial Fibrillation: The Atrial Fibrillation Investigators
Background and Purpose — Stroke risk increases with age in patients who have nonvalvular atrial fibrillation . It is uncertain whether the efficacy of stroke prevention therapies in atrial fibrillation changes as patients age . The objective of this study was to determine the effect of age on the relative efficacy of oral anticoagulants ( OAC ) and antiplatelet ( AP ) therapy ( including acetylsalicylic acid and triflusal ) on ischemic stroke , serious bleeding , and vascular events in patients with atrial fibrillation . Methods — This is an analysis of the Atrial Fibrillation Investigators data base , which contains patient level- data from r and omized trials of stroke prevention in atrial fibrillation . We used Cox regression models with age as a continuous variable that controlled for sex , year of r and omization , and history of cerebrovascular disease , diabetes , hypertension , and congestive heart failure . Outcomes included ischemic stroke , serious bleeding ( intracranial hemorrhage or systemic bleeding requiring hospitalization , transfusion , or surgery ) , and cardiovascular events ( ischemic stroke , myocardial infa rct ion , systemic embolism , or vascular death ) . Results — The analysis included 8932 patients and 17 685 years of observation from 12 trials . Patient age increased risk of ischemic stroke ( adjusted hazard ratio per decade increase 1.45 ; 95 % CI , 1.26 to 1.66 ) , serious bleeding ( 1.61 ; 1.47 to 1.77 ) , and cardiovascular events ( 1.43 ; 1.33 to 1.53 ) . Compared with placebo , OAC and AP significantly reduced the risk of ischemic stroke ( OAC , 0.36 ; 0.29 to 0.45 ; AP , 0.81 ; 0.72 to 0.90 ) and cardiovascular outcomes ( OAC , 0.59 ; 0.52 to 0.66 ; AP , 0.81 ; 0.75 to 0.88 ) , whereas OAC increased risk of serious bleeding ( 1.56 ; 1.03 to 2.37 ) . The relative benefit of OAC versus placebo or AP did not vary by patient age for any outcome . Compared with placebo , the relative benefit of AP  for preventing ischemic stroke decreased significantly as patients aged ( P=0.01 ) . Conclusions — As patients with atrial fibrillation age , the relative efficacy of AP to prevent ischemic stroke appears to decrease , whereas it does not change for OAC . Because stroke risk increases with age , the absolute benefit of OAC increases as patients get older
The various risk stratification schemes classified variable proportions as low , moderate and high risk , but the CHA(2)DS(2)-VASc score classified the smallest proportion of patients as ' low risk ' .
Anticoagulation with vitamin K antagonists and dabigatran is cost-effective in patients at high risk of stroke , but not in patients without any other stroke risk factor beside AF .