Abstract Body: Introduction: Prospective, controlled clinical trials have suggested that prehospital management in a mobile stroke unit (MSU) improves functional outcomes in intravenous (IV) thrombolysis-eligible patients. However, because MSUs are dispatched prior to knowledge of the diagnosis, an examination of their real-world effectiveness must include all patients for whom stroke is suspected. The objective of this study was to determine the association between MSU management vs. EMS management and outcomes in all patients with suspected stroke in the prehospital setting.

Methods: We performed a retrospective, observational, cohort study from the American Heart Association’s Get With The Guidelines®-Stroke (GWTG-Stroke) Program between August 1^st 2018 and January 31^st 2023. At participating hospitals receiving both MSU-managed and standard EMS-managed patients, all patients with stroke-like symptoms in the prehospital setting were analyzed. The primary efficacy end point was the level of global disability assessed with the utility-weighted modified Rankin Scale (UW-mRS; rage 0.00 – 1.00). The secondary efficacy end point was ambulatory status. The co-primary safety end points were symptomatic intracranial hemorrhage (sICH) and in-hospital mortality.

Results: Of 108,684 patients (median age 73 [Q1,Q3: 62,83]; 51.2% female), 4,218 (3.9%) received prehospital management in an MSU. Prehospital management in an MSU was associated with a better score on the UW-mRS at discharge (adjusted mean difference 0.05 [95% CI: 0.03 – 0.06]) and a higher likelihood of independent ambulation at discharge (51.0% [1,521/2,985] vs. 47.8% [31,450/79,699]; aRR 1.11 [95% CI: 1.08 – 1.15]; adjusted risk difference 5.2% [95% CI: 3.7 to 6.8]). There was no statistically significant difference in sICH (4.0% vs. 4.1%; aRR 1.02 [95% CI: 0.82 – 1.25]). There was a lower rate of in-hospital mortality (6.4% vs. 8.7%; aRR: 0.78 [95% CI: 0.71 to 0.87]) in MSU-treated patients.

Conclusions: Among patients with stroke-like symptoms in the prehospital setting, prehospital management in an MSU compared with EMS management was associated with a significantly lower level of global disability. These findings support policy efforts to expand access to MSU care in the United States.