Abstract MP48: Racial And Urban-rural Disparities In The Frequency Of Ischemic Stroke As First Manifestation Of Atrial Fibrillation

Introduction: Atrial fibrillation (AF) may be asymptomatic and remain undiagnosed until the development of complications, which precludes primary prevention efforts. We aimed to quantify racial and rural-urban disparities in the frequency of incident AF presenting with ischemic stroke in a nationally representative sample of Medicare beneficiaries. Hypothesis: Black patients have higher frequency of stroke as the first presentation with AF than White patients. Methods: We used a 5% random sample of Medicare claims data to identify patients newly diagnosed with AF in 2016. The primary outcome was stroke as first AF manifestation, and was defined by inpatient diagnosis of ischemic stroke within 7 days prior to the first AF diagnosis. We computed age- and sex-adjusted proportion of AF diagnosis manifesting as stroke and used multivariable logistic regression to quantify the association of race and urban/rural residence with the outcome, adjusting for demographic and clinical characteristics. Results: Among 39,437 patients newly diagnosed with AF, 2,821 (7.2%) had ischemic stroke as the first AF manifestation. In urban areas, age- and sex-adjusted proportions of AF diagnosis manifesting as stroke were 7.2(95%CI: 6.8,7.4)% for White and 9.5(8.4,10.8)% for Black, compared to 5.9(5.4,6.4)% and 8.1(5.8,11.1)% in rural areas ( Figure ). After adjusting for age, sex, CHA 2 DS 2 -VASc score, Alzheimer's disease, Medicaid enrollment, and receipt of low-income subsidy, Black race (adjusted OR [95%CI]: 1.21 [1.05, 1.40], vs. White) and urban residence (1.16 [1.06, 1.28], vs. rural) were associated with increased risk of stroke as first AF manifestation. Conclusion: We observed uneven distributions in the frequency of stroke as first manifestation of AF between White and Black patients and between rural and urban residents. Further research is needed to evaluate the effectiveness of AF screening efforts in reducing inequities in health outcomes associated with AF.