Purpose Combined oral anticoagulant (OAC) and antiplatelet (AP) therapy is generally discouraged in atrial fibrillation (AF) outside of acute coronary syndromes or stenting because of increased bleeding. We evaluated its frequency and possible reasons in a contemporary European AF population.

Methods The PREvention oF thromboembolic events–European Registry in Atrial Fibrillation (PREFER in AF) prospectively enrolled AF patients in France, Germany, Austria, Switzerland, Italy, Spain and the UK from January 2012 to January 2013. We evaluated patterns of combined VKA-AP therapy in this population.

Results Out of 7243 patients enrolled, 5170 (71.4%) were treated with OAC alone, 808 (11.2%) with AP alone and 791 (10.9%) with a combination of OAC and one (dual) or two AP (triple combination therapy). Compared with patients only prescribed OAC, patients on combination treatment had similar Body Mass Index, but more frequently diabetes (p<0.05), dyslipidaemia (p<0.01), coronary heart disease (54.2 vs 18.6%; p<0.01) or peripheral arterial disease (10.2 vs 3.7%; p<0.01). Accordingly, they had a higher mean CHA₂DS₂VASc (3.7 vs 3.4), and HAS-BLED (2.7 vs 1.9) scores (for both, p<0.01).

Of the 660 patients on dual AP+OAC combination therapy, 629 (95.3%) did not have an accepted indication. Out of the 105 patients receiving triple combination therapy, 67 (63.8%) did not have an accepted indication.

Conclusions The combined use of OAC and AP therapy is not uncommon in AF, largely inappropriate, explained by the coexistence of coronary or peripheral arterial disease, and not influenced by considerations on the risk of bleeding.