Abstract DP205: Acute Stroke Transfers Down Trending Since 2019 Despite Thrombectomy Increase

Introduction: Stroke transfer networks are rapidly changing. Prior stroke transfers studies have largely been regional and predate the widespread use of endovascular thrombectomy (EVT). We characterized: 1. national trends in interfacility transfer for stroke and 2. hospital-level and regional factors associated with transfer. Methods: Using 2016-2022 US Centers of Medicare 100% Fee-For-Service claims, we captured patients over age 65 who were hospitalized with a final diagnosis of ischemic stroke and initially presented to an ED. Transfer status, tPA, EVT, and demographics were characterized with validated claims-based definitions. ED and inpatient facility characteristics were obtained from Medicare. Descriptive statistics compared the transfer population to two populations: 1. Admission to the presenting ED of transferring hospitals and 2. Direct presentation to a transfer-accepting hospital. Amongst patients presenting to a transferring hospital requiring admission, logistic regression was used to predict the dependent variable, transfer, adjusting for independent variables: year, sex, age, race, comorbidities, tPA, EVT, income, presenting ER region, rurality, teaching status, stroke center status, Area Deprivation Index (ADI), size, and ownership type. Results: Ischemic stroke transfers increased from 2016 to 2019 then declined through 2022 [2016=21,221; 2019=26,720; 2022=21,902]. Transferred patients with EVT only over this period increased [2016=1082; 2022=3531], while those with tPA only declined slightly [2016=4494; 2022=3863](Figure 1). In our adjusted model, the strongest patient-level factors associated with probability of transfer were: older age [1 SD change in age (~8 years) has OR 0.591, 95% CI: 0.579-0.603] and presence of dementia [OR 0.715, 95% CI: 0.698-0.733]. A number of hospital and regional factors were associated with transfer including: geographic region [West region OR 0.617, 95% CI: 0.503-0.756 (Northeast reference)], presentation hospital size [>400 beds OR 0.006, 95% CI: 0.005-0.008 (