Treatments and Patient Outcomes Following Stroke Center Expansion.

Importance: It is unclear how certified stroke center expansion contributes to improved access to stroke treatment and patient outcomes, and whether these outcomes differ by baseline stroke center access. Objective: To examine changes in rates of admission to stroke centers, receipt of thrombolysis and mechanical thrombectomy, and mortality when a community gains a newly certified stroke center within a 30-minute drive. Design, Setting, and Participants: This cohort study compared changes in patient outcomes when a community (defined by area zip code) experienced a stroke center expansion relative to the same community type that did not experience a change in access. Medicare fee-for-service beneficiaries with a primary diagnosis of acute ischemic stroke who were admitted to hospitals between January 1, 2009, and December 31, 2019, were included. The data analysis was performed between October 1, 2023, and September 9, 2024. Exposure: New certification of a stroke center within a 30-minute driving time of a community. Main Outcomes and Measures: The main outcomes were rates of admission to a certified stroke center, receipt of thrombolytics (delivered using drip-and-ship and drip-and-stay methods), mechanical thrombectomy, and 30-day and 1-year mortality estimated using a linear probability model with community fixed effects. Results: Among the 2 853 508 patients studied (mean [SD] age, 79.5 [8.5] years; 56% female), 66% lived in communities that had a stroke center nearby at baseline in 2009, and 34% lived in communities with no baseline access. For patients without baseline access, after stroke center expansion, the likelihood of admission to a stroke center increased by 38.98 percentage points (95% CI, 37.74-40.21 percentage points), and receipt of thrombolytics increased by 0.48 percentage points (95% CI, 0.24-0.73 percentage points). Thirty-day and 1-year mortality decreased by 0.28 percentage points (95% CI, -0.56 to -0.01) and 0.50 percentage points (95% CI, -0.84 to -0.15 percentage points), respectively, after expansion. For patients in communities with baseline stroke center access, expansion was associated with an increase of 9.37 percentage points (95% CI, 8.63-10.10 percentage points) in admission to a stroke center but no significant changes in other outcomes. Conclusions and Relevance: In this cohort study, patients living in communities without baseline stroke center access experienced significant increases in stroke center admission and thrombolysis and a significant decrease in mortality after a stroke center expansion. Improvements were smaller in communities with preexisting stroke center access. These findings suggest that newly certified stroke centers may provide greater benefits to underserved areas and are an important consideration when deciding when and where to expand health care services.