The combined use of vitamin K antagonists and antiplatelet agents in atrial fibrillation - patterns of use in the European PREFER in AF registry

Abstract

Purpose: The combined long-term use of vitamin K antagonists (VKA) and antiplatelet (AP) agents in patients with atrial fibrillation (AF) is generally discouraged because it entails increased risk of bleeding in the face of uncertain efficacy benefits. Therefore we evaluated the frequency of such prescription pattern and comorbidity associations. Methods: The PREvention oF thromboembolic events – European Registry in Atrial Fibrillation (PREFER in AF) prospectively enrolled patients with AF in France, Germany, Austria, Switzerland, Italy, Spain and the United Kingdom from Jan 2012 to Jan 2013. Here, we report the patterns of combined therapy with anticoagulants and (single or dual) AP therapy in this population. Results: In 7243 patients enrolled, 4799 (66.3%) were treated with a VKA (warfarin, phenprocoumon, acenocoumarol, fluindione), 808 (11.2%) with an AP alone, and 720 (9.9%) with a VKA + AP (88.8% with ASA, 21.0% with clopidogrel, 3.1% with another AP). Compared with patients only prescribed a VKA, patients on combination treatment had similar age and body mass index, but more often had paroxysmal (28.1 vs. 23.5%) or persistent (29.7 vs. 23.5%) AF (for both, p<0.01), a significantly higher prevalence of diabetes, obesity, dyslipidaemia and chronic renal insufficiency (for all, p<0.05), and significantly more frequent coexisting coronary heart disease (CHD) (58.9 vs. 19.0%; p<0.01) or peripheral arterial disease (PAD) (10.6 vs. 3.8%; p<0.01). Accordingly they had a higher mean CHA2DS2VASc score (3.8 vs. 3.5), and a higher mean HAS-BLED score (2.8 vs. 1.9) (for both, p<0.01). Most of the combination treatments were judged by all means inappropriate according to the 2010/2012 ESC guidelines, not being given because of recent stenting or an acute coronary syndrome. Detailed analyses on the appropriateness of combination therapy will be presented. Conclusions: The combined use of VKA and AP therapy is common in Europe, largely explained by the coexistence of AF with CHD or PAD, and not influenced by considerations on the risks of bleeding or thromboembolism. Such prescription patterns should be the target of appropriate guideline implementation programmes.