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 (<100 beds reference)], and presenting ER county ADI [4 th quartile (most affluent) OR 0.602, 95% CI: 0.486-0.745 (1 st quartile reference)](Table 2). Conclusion: Transfers for patients with ischemic stroke without emergent intervention have decreased since 2019, while EVT transfers have increased. Marked regional differences in transfer practices exist and less affluent regions are more likely to transfer.