Improved Stroke Prevention in Atrial Fibrillation After the Introduction of Non-Vitamin K Antagonist Oral Anticoagulants.

Background and Purpose- The purpose of this study was to investigate the impact of improved antithrombotic treatment in atrial fibrillation after the introduction of non-vitamin K antagonist oral anticoagulants on the incidence of stroke and bleeding in a real-life total population, including both primary and secondary care. Methods- All resident and alive patients with a recorded diagnosis for atrial fibrillation during the preceding 5 years in the Stockholm County Healthcare database (Vårdanalysdatabasen) were followed for clinical outcomes during 2012 (n=41 008) and 2017 (n=49 510). Results- Pharmacy claims for oral anticoagulants increased from 51.6% to 73.8% (78.7% among those with CHA2DS2-VASc ≥2). Non-vitamin K antagonist oral anticoagulant claims increased from 0.4% to 34.4%. Ischemic stroke incidence rates decreased from 2.01 per 100 person-years in 2012 to 1.17 in 2017 (incidence rate ratio, 0.58; 95% CI, 0.52-0.65). The largest increases in oral anticoagulants use and decreases in ischemic strokes were seen in patients aged ≥80 years who had the highest risk of stroke and bleeding. The incidence rates for major bleeding (2.59) remained unchanged (incidence rate ratio, 1.00; 95% CI, 0.92-1.09) even in those with a high bleeding risk. Poisson regression showed that 10% of the absolute ischemic stroke reduction was associated with increased oral anticoagulants treatment, whereas 27% was related to a generally decreased risk for all stroke. Conclusions- Increased oral anticoagulants use contributed to a marked reduction of ischemic strokes without increasing bleeding rates between 2012 and 2017. The largest stroke reduction was seen in elderly patients with the highest risks for stroke and bleeding. These findings strongly support the adoption of current guideline recommendations for stroke prevention in atrial fibrillation in both primary and secondary care.