Regional differences in use of antithrombotic therapy for stroke prevention in atrial fibrillation and associated outcomes: European and Asian insights

Abstract

Purpose: Few data are available on clinical outcomes in patients with atrial fibrillation (AF) in the Asian region compared with those in Europe. Methods: The population comprised consecutively recruited patients with newly diagnosed (≤6 weeks) non-valvular AF and one or more investigator-defined stroke risk factor(s). The effect of region (Asia vs Europe) on clinical outcomes at 1 year was investigated using a Cox proportional hazards model, adjusting for components of the CHA2DS2VASc risk scheme. Results: Of the 10,614 GARFIELD patients, 2589 were enrolled in Asia (mean age±SD 66±12 years; 38% women) and 6580 in Europe (mean age 72±11 years; 45% women). Mean risk scores were lower in the Asian population: CHADS2 1.6±1.1 vs 2.0±1.2; CHA2DS2VASc 2.7±1.6 vs 3.4±1.6; HAS-BLED 1.2±0.9 vs 1.3±0.9; all p<0.001. Overall use of VKAs initiated at diagnosis of AF was higher in Europe (65% vs 38% in Asia) and antiplatelet use lower (20% vs 37%); 20% of Asian patients received no antithrombotic treatment vs 12% of those in Europe (p<0.001 for overall treatment). VKA use was lower in Asia than in Europe irrespective of risk level (CHA2DS2-VASc <2: 35% vs 58%, respectively, p<0.001; score ≥2: 42% vs 67%, p<0.001). Despite lower overall use of VKAs in Asia, stroke/systemic embolism rates were similar; risk of major bleeding was lower (Table). View this table: Adjusted HRs for events at 1 year Conclusion: These multinational observational data from the GARFIELD Registry suggest that a more risk-based approach to VKA treatment at diagnosis may be applied in Asia versus Europe, resulting in a lower rate of bleeding and equivalent rate of stroke/systemic embolism.