Abstract TP163: Associations Between Prior Oral Anticoagulant Use and Stroke Outcomes in a National Stroke Cohort: A Scottish Database Study

Abstract

Background and aims: Recent studies suggest that oral anticoagulant (OAC) use prior to stroke is associated with better functional outcomes after ischaemic stroke, but worse outcomes after non-traumatic intracerebral haemorrhage (ICH). We aimed to assess the impact of prior OAC use on stroke subtype and outcomes (mortality and discharge to home) in a Scottish stroke cohort. Methods: Data on first-ever strokes between January 1, 2011, and December 31, 2018, were gathered from the Scottish Stroke Care Audit. The Prescribing Information System was used to identify patients with a prescription for OAC within 90-days before stroke, and further linked to hospital admission and discharge data in the Scottish Morbidity Record 01, and mortality data in the National Records of Scotland. Multivariable logistic regression models were adjusted for sociodemographic factors, atrial fibrillation, stroke severity, acute management and Charlson Comorbidity scores. Results: Among 52 988 stroke patients (50.1% women; mean age 72.8 [±13.3] years), 88.9% were ischaemic and 18.3% had a history of atrial fibrillation. OACs (warfarin [73%] and direct oral anticoagulants [28%]) were prescribed to 3533 (7.5%) patients with ischaemic stroke and 847 (14.4%) patients with ICH within 90 days prior to first-ever stroke. After model adjustments, prior OAC use was associated with a three-fold increase in the odds of experiencing an ICH (adjusted Odds Ratio [aOR], 2.92; 95% CI, 2.61 - 3.26]). In patients with ischaemic stroke or ICH, prior OAC use was not associated with better or worse outcomes in 30-day discharge to usual place of residence (aOR, 0.99; 95% CI, 0.89 - 1.09 and aOR, 0.86; 95% CI, 0.66 - 1.12 respectively) or 30-day mortality (aOR, 1.06; 95% CI, 0.94 - 1.21 and aOR, 1.20, 95% CI, 0.93 - 1.56 respectively) in comparison to those with no prior OAC use. Additionally, no statistically significant differences were observed for discharge or mortality outcomes within 90 days after stroke. Conclusions: Prior OAC use was higher in patients with ICH, which may partly reflect ischaemic stroke reduction in patients taking OAC. However, prior OAC use was not associated with better or worse outcomes in terms of mortality and discharge to home in either ischaemic or ICH populations.