Changes in anticoagulation practice in subjects admitted with stroke associated with atrial fibrillation, following introduction of direct oral anticoagulants over 2013-2021

Background: The adoption of direct oral anticoagulants (DOACs) has changed practice in prevention of stroke in atrial fibrillation (AF). We used Irish data national data on stroke and anticoagulation therapy over 9 years to investigate changes in anticoagulation practice and potential consequences on stroke prevalence and thrombolysis.Methods: AF, anticoagulation, thrombolysis, and stroke data from the Irish National Audit of Stroke (INAS) 2013-2021 were reviewed. The proportion of patients with ischemic stroke (IS) and intracerebral hemorrhage (IH) with known AF admitted on anticoagulation was determined. Effects on age distribution in the population and thrombolysis practice were assessed.Results: AF data were available on 34,630 of 35,241 individuals (98.3%) included in INAS; median age was 74 years and 56% were male. AF was found in 10,016 (28.9%, 9059 IS, 957 IH). 6313 had known AF prior to stroke (63.1%). The proportion all total IS due to AF decreased by 15.3% (31.3%-26.5%, chi-square = 24.6, p < 0.0001). The proportion of IH did not change significantly (21.6%-20.2%, chi-square = 1.8, p = 0.18). Over the 9 years, 3875 (38.6%) of the subjects with AF were recorded as receiving anticoagulants at admission. In 2013, 4.4% of AF-associated strokes were admitted on a DOAC and 21.4% on warfarin; by 2021, 44.1% were receiving a DOAC and 6.2% warfarin. There was a strong inverse correlation between the proportion of anticoagulated stroke patients and the total proportion of AF-associated strokes over time (r = -0.82, p = 0.006). In contrast, no correlation was found between increasing DOAC usage and IH (r = 0.14, p = 0.71). Increased anticoagulation usage correlated with a reduction in patients > 80 years (r = -0.83, p = 0.006) and also correlated with a relative reduction of 30.1% in subjects thrombolysed <4 h from onset (r = -0.89, p = 0.001)Conclusion: DOACs have led to increased use of anticoagulation, but warfarin use fell by two-thirds. There has been a reduction in the proportion of AF-associated IS without a noticeable increase in IH. Increased anticoagulation correlated with reduced numbers of strokes in those >80 years and in the proportion of patients thrombolysed.