Association of Mobile Stroke Unit Care and Spending, Utilization, and Mortality in New York City

Background: Transport by mobile stroke units (MSUs), which provide access to computed tomography scanning and intravenous blood pressure medications and thrombolytics, reduces time to treatment and may improve short-term functional outcomes for patients with acute stroke. The longer-term clinical and financial impacts remain incompletely understood. Objective: Determine whether MSU care is associated with better health, utilization, and spending outcomes for patients with suspected acute stroke. Design: Retrospective, observational study of Medicare patients transported by MSUs versus traditional ambulances in New York City, from October 2016 to December 2019. Eligibility: 167 Medicare patients with suspected acute stroke transported by MSU and 2,518 propensity-score matched controls. Main Outcomes: Primary outcomes included length of stay and discharge destination at index hospitalization, as well as risk of repeat hospitalization, number of emergency department visits, total costs of care, and mortality at 1 year. Results: Of 167 patients (mean age, 79.9 years;56.3% women) transported by a MSU for suspected acute stroke, 61.1% had an ischemic stroke/TIA, 7.8% had an intracerebral hemorrhage, and 31.1% had a stroke mimic or other diagnosis. Compared to propensity-score matched control patients, MSU patients experienced similar lengths of stay (5.9 vs 6.7 days,p=0.13) and were similarly likely to be discharged to a skilled nursing facility (15.6% vs 15.1%,p=0.86). They had clinically but marginally significant lower rates of mortality at 1 year (21.6% vs 28.4%; difference, 6.8 percentage points [95% CI -13.3 to 0.3,p=0.058). They had similar rates of any repeat hospitalization (24% vs 23.2%,p=0.82) and ED visits without hospitalization (14% vs 12%,p=0.86), and there were no significant differences in total spending or specific types of spending. Conclusions: In this study of patients presenting with suspected acute stroke in New York City, transport by MSUs, compared with traditional ambulances, was associated with a trend toward lower mortality at 1 year. Prospective trials and replication in other regions are warranted. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by NewYork-Presbyterian. NewYork-Presbyterian had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Weill Cornell IRB Board approved this research proposal. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Medicare claims can be accessed upon application to the Center for Medicare and Medicaid Services. EHR data can be accessed upon application to the Tripartite Request Assessment Committee (TRAC). The New York City mobile stroke registry is not available as it includes identifiable participant data and protected health information.