Abstract TP149: Prevalence of Antiphospholipid Syndrome in Acute Stroke: A Nationwide Analysis

Introduction: Antiphospholipid syndrome(APS) is an underrecognized cause of acute ischemic stroke(AIS). Early diagnosis of APS is essential as proper secondary prevention with vitamin K antagonists can reduce risk of recurrent stroke. Though APS is thought to be an uncommon stroke etiology, the true prevalence of APS in AIS is unknown. In this study, we aimed to (1)determine the prevalence of APS in AIS and (2)characterize its clinical phenotype. Methods: Using the National Inpatient Sample(NIS), we conducted a large, retrospective cross-sectional study of a stratified sample of all hospital admissions in the United States from 2016 to 2022. All adult patients hospitalized with AIS were identified and separated into two groups based on the presence or absence of a diagnosis of APS. The prevalence of APS in AIS was calculated using the NIS derived discharge weights. Demographic, risk factors, acute treatments and in-hospital outcomes were compared. Results: Of 4,407,923 admissions for AIS between 2016 and 2022, 14,350 patients had AIS with APS, a 0.3% prevalence among all AIS patients. This prevalence increased 4.7 fold for stroke in young patients (age 18-50, prevalence 1.4%). APS with AIS patients were more likely to be younger(55.0 vs 69.8, p value