Use of risk scores in anticoagulation
Such tools improve practice and decision making
Atrial fibrillation is the commonest abnormal cardiac rhythm, affecting 1-2% of the general population, and its incidence is rising. The prevalence of atrial fibrillation increases with age, reaching 5-15% at 80 years.1 Other important risk factors include hypertension, diabetes, and valvular heart disorders.2 Atrial fibrillation is classified as acute, paroxysmal, persistent, or permanent (see box).
Atrial fibrillation is associated with a fivefold increase in the risk of stroke.13 Stroke in atrial fibrillation is believed to be the result of embolisation of a left atrial thrombus, formed secondary to blood stasis. Compared with placebo, warfarin and aspirin reduce the risk of stroke by 64% and 22% respectively.4 Adjusted dose warfarin is substantially more effective than aspirin (39% relative risk reduction).45 However, starting warfarin is not a small undertaking for the patient, who has to undergo lifelong monitoring, adopt lifestyle changes, and be subject to an increased risk of bleeding. Patients must