Anticoagulation in people with atrial fibrillation

A cornerstone of managing patients with atrial fibrillation is deciding whether or not to prescribe an anticoagulant. Despite strong evidence supporting the efficacy of anticoagulants in preventing thromboembolism related to atrial fibrillation,1 many people with atrial fibrillation—even those with multiple risk factors for stroke—are not prescribed these drugs.2 To help clinicians decide on which management path to choose, several tools have been developed to estimate the risk of stroke on the basis of clinical factors.3 4 The performance of two such risk tools is described in the linked cohort study by Olesen and colleagues (doi:10.1136/bmj.d124)⇓.5

One widely used risk scheme is the CHADS₂ index, an acronym representing Congestive heart failure, Hypertension, Age over 75, Diabetes, and previous Stroke, which can easily be applied in general clinical practice.6 However, like other risk schemes, this index is only moderately accurate at separating patients into different categories of stroke risk.3 4 7 Large numbers of patients considered at high risk for stroke—in whom anticoagulants would be recommended—will not have a …