Optimising stroke prevention in patients with atrial fibrillation: Application of the GRASP-AF audit tool in a UK general practice cohort

Abstract

Background: Oral anticoagulation (OAC) is recommended for effective stroke prevention in the majority of atrial fibrillation patients but is often under-utilised. Aim: To use the Guidance on Risk Assessment and Stroke Prevention in the Atrial Fibrillation (GRASP-AF) tool to risk stratify patients, identify antithrombotic therapy received, and determine predictors of stroke and death in a UK general practice cohort. Design and setting: Retrospective-observational cohort study in 11 general practices in Darlington, England, with 105 000 patients. Method: The study included patients with atrial fibrillation (AF) identified from GP databases using the GRASP-AF tool. Stroke risk was determined by CHADS2 and CHA2DS2-VASc scores. Results: A total of 2259 (2.15%) patients with AF (mean age 76 years [SD 12]; 46% female) were identified. Use of CHA2DS2-VASc rather than CHADS2 increased the proportion eligible for OAC from 86.0% to 92.5%. Of those with CHA2DS2-VASc score of ≥2, 39.7% were not receiving appropriate OAC, and of those with CHADS2 score of ≥1, 39.5% were not receiving appropriate OAC. Antiplatelet monotherapy was utilised in 33-40% of patients at high risk of stroke. During 12-month follow-up, 67 (3.0%) patients experienced a stroke and 214 (9.5%) died. Use of OAC significantly reduced stroke risk (odds ratio [OR] 0.60, 95% confidence intervals [CI] = 0.45 to 0.81) and death (OR = 0.54, 95% CI = 0.38 to 0.75, P<0.001) among patients at moderate-high risk of stroke. Use of antiplatelet agents also independently predicted death (OR = 0.69, 95% CI = 0.50 to 0.94; P = 0.020). Conclusion: Most patients with AF in general practice are at high risk of stroke, but OAC is under-utilised in about 40%. Risk of stroke and death was significantly reduced by OAC, yet antiplatelet monotherapy was inappropriately used in approximately 25% of patients at risk of stroke. Optimal implementation of the CHA2DS2-VASc score in the GRASP-AF tool could help prevent more strokes annually.