Published online by Cambridge University Press: 21 December 2006
Meta-analyses of randomized controlled trials have reported the efficacy of dose-adjusted warfarin therapy (target International Normalised Ratio (INR) 2–3) in reducing stroke risk in atrial fibrillation by 68%, with aspirin reducing relative risk by 22%. Absolute benefit for an individual patient depends on the presence of the risk factors for stroke; these include previous stroke, transient ischaemic attack, hypertension, diabetes, valvular heart disease, heart failure and advanced age. In spite of reported benefit, many people with atrial fibrillation and a high risk of stroke are not receiving anticoagulation: disappointingly, risk stratification is not being sufficiently used to guide treatment.