Predicted risk of stroke and bleeding and use of oral anticoagulants in atrial fibrillation: Danish nationwide temporal trends 2011-2016.

INTRODUCTION, MATERIALS AND METHODS: We used Danish nationwide registries to examine temporal trends in the predicted stroke and bleeding risks (mean CHA2 DS2 -VASc and HAS-BLED scores per year, respectively) as well as the combination of selected stroke and bleeding risk factors per year among atrial fibrillation (AF) patients initiated for the first time between 2011 and 2016 on vitamin K antagonists (VKAs), dabigatran, rivaroxaban, or apixaban.

RESULTS: In total, 53,860 AF patients were included (VKA 37.7%, dabigatran 24.4%, rivaroxaban 16.9%, apixaban 21.0%). For standard dose dabigatran initiators, during almost all of the study period, the mean CHA2 DS2 -VASc and HAS-BLED scores were the lowest and decreased (2.6 and 2.2 in 2011 vs. 2.1 and 1.8 in 2016, respectively). Reduced dose apixaban initiators had rather stable mean CHA2 DS2 -VASc scores during the study period and the highest mean CHA2 DS2 -VASc score in 2016 (4.1). The mean HAS-BLED scores were similarly high among reduced dose apixaban and rivaroxaban initiators in years 2013-2016. From 2011 to 2014, a decrease in the frequency of prior stroke (p<0.001), age≥75years (p<0.001), and prior bleeding (p=0.007) was observed among dabigatran initiators. In the study period, apixaban initiators in general had the highest frequency of prior stroke and age≥75years.

CONCLUSIONS: Danish AF patients receiving standard dose dabigatran had the lowest and decreasing predicted stroke and bleeding risks during almost all study years. Patients receiving reduced dose apixaban had rather stable predicted risk of stroke during the study period and the highest mean CHA2 DS2 -VASc score in 2016.