Abstract 10485: Case Fatality and Prior Anticoagulation in Patients with Atrial Fibrillation and First-Ever Ischemic Stroke

Introduction: Thromboprophylaxis of patients with atrial fibrillation (AF) has changed in the past decade. How the changes manifest in real life is yet less studied. This study describes 30-day case fatality and prior anticoagulation in a nationwide cohort of patients with AF and first-ever ischemic stroke during the past decade. Methods: FinACAF (Finnish Anticoagulation in Atrial Fibrillation) is a registry-linkage study. Data were collected from several nationwide registries. We followed patients with incident AF between 2009 and 2017 with first-ever ischemic stroke between January 2009 and November 2018. Cox regression model was used to estimate the associations between 30-day case fatality and oral anticoagulation (OAC) if purchased 90 days preceding the stroke, adjusting for age, sex, time of AF diagnosis relative to stroke (new-onset AF vs. prior diagnosis), and stroke year. Results: Altogether, 17,924 patients (55% female, median age 79 years with interquartile range 71-86) suffered from first-ever ischemic stroke. Crude 30-day case fatality was 15.4% (95% confidence interval 14.9-15.9, p=0.037). Prior NOAC (hazard ratio 0.69, 0.57-0.84, p<0.001) and prior warfarin (0.78, 0.71-0.86, p<0.001) usage were both associated with lower case fatality compared to those without any OAC in use. There was no significant difference between previous warfarin and NOAC usage. Older age and AF diagnosis registered before the stroke, as opposed to AF diagnosis first recognized together with stroke, were associated with higher case fatality. There was no significant difference between 30-day case fatality when comparing cases by the event year (1.00, 0.98-1.01, p=0.739). Conclusion: Previously recorded AF diagnosis was associated with higher 30-day case fatality, although prior use of warfarin and NOAC were associated with decreased mortality compared to no prior OAC use.