Results Summary
What was the research about?
A stroke happens when blood clots block blood supply to the brain. Strokes can cause disability or death. If patients receive treatment with medicine quickly, they may have a better recovery.
In this study, the research team compared two approaches to treat patients suspected of having a stroke who called 911:
- Mobile stroke units, or MSUs. MSUs are ambulances with special equipment and staff who can diagnose and treat stroke. MSU staff evaluated each patient when the MSU ambulance arrived to answer the 911 call. If the patient had had a stroke, MSU staff took blood samples and x-rays to see if the patient could receive medicine to break up blood clots. MSU staff gave medicine to the patient in the ambulance, then took them to a stroke center emergency room, or ER. The MSU staff included paramedics, nurses, and an x-ray technician.
- Standard ER care. Paramedics picked up the patient in an ambulance. They asked the patient about their medical history, checked their blood sugar, and took them to a stroke center ER. Staff at the ER took blood samples and x-rays to see if the patient could receive medicine to break up blood clots. ER staff gave medicine to the patient based on their test results.
What were the results?
Three months after a stroke, compared with standard ER care, patients treated in an MSU were more likely to recover from the stroke without disability. Also, patients treated in an MSU received medicine to treat the stroke 36 minutes sooner, on average, than those receiving standard ER care.
The two approaches didn’t differ in patient quality of life, survival, or healthcare use.
Who was in the study?
The study included 1,047 patients ages 18 and older treated for stroke in one of seven cities across the United States. Of these patients, 54 percent were White, 39 percent were Black, 4 percent were Asian, and 3 percent were another race or didn’t report a race; 17 percent were Hispanic or Latino. The average age was 66, and 51 percent were women.
What did the research team do?
The research team worked with emergency medical services (EMS) to provide care for patients who might have had a stroke. From August 2014 until August 2020, the response to 911 calls for these patients switched each week between the two approaches to treat stroke.
The research team interviewed patients and caregivers about the patient’s level of disability three months after their stroke. Patients and caregivers completed surveys about the patient’s quality of life and healthcare use at the start of the study and every three months for one year after their stroke.
Patients with a history of stroke and EMS staff helped design the study.
What were the limits of the study?
The study took place in seven cities. Results may differ in rural areas.
Future research could compare MSUs and standard ER care in rural areas.
How can people use the results?
Health systems can use the results when considering ways to treat patients who have had a stroke.
Professional Abstract
Objective
(1) To compare the effectiveness of mobile stroke unit (MSU) treatment versus standard emergency department (ED) management in reducing disability level among patients who have had a stroke; (2) To compare the effect of MSU treatment versus standard ED management on healthcare utilization after stroke
Study Design
| Design Element | Description |
|---|---|
| Design | Observational: prospective study |
| Population | 1,047 patients ages 18 and older who had had a stroke in 7 cities across the United States and were eligible to receive tPA |
| Interventions/ Comparators |
|
| Outcomes | Primary: recovery without disability, defined as 0 or 1 on the Modified Rankin Score Secondary: time from symptom onset to tPA treatment, survival, healthcare utilization, quality of life |
| Timeframe | 3-month follow-up for primary outcome |
This prospective, multi-center, cluster-controlled trial compared the effectiveness of MSU treatment versus standard ED management in reducing disability level and increasing survival and quality of life among patients who had a stroke. The trial also examined the effects of these treatments on healthcare utilization after stroke.
Researchers collaborated with emergency medical services (EMS) in seven cities across the United States to provide care to patients suspected of having a stroke. From August 2014 until August 2020, the response to 911 calls for these patients alternated weekly between two methods:
- MSU. The MSU team arrived on scene and evaluated patients’ symptoms to determine if they had had a stroke. The team included paramedics, a computed tomography (CT) technician, a critical care nurse, and a vocational nurse. The team collected blood samples and performed a CT scan and determined if the patient was eligible to receive tissue plasminogen activator (tPA). Eligible patients received tPA and transport to a stroke center.
- Standard ED management. EMS paramedics collected patients’ medical history and blood sugar levels during transport to the nearest stroke center ED. There, a stroke team managed patients according to the stroke centers’ protocol and gave eligible patients tPA.
The study included 1,047 patients ages 18 and older and eligible to receive tPA. Of these, 54% were White, 39% were Black, 4% were Asian, and 3% were another race or did not report race; 17% were Hispanic or Latino. The average age was 66, and 51% were female.
Researchers, who were blind to group assignment, interviewed patients and their caregivers about the patient’s level of disability three months after their stroke. Patients and caregivers completed a survey about their quality of life and healthcare utilization at baseline and every three months for one year after their stroke.
Patients with a history of stroke and EMS staff helped design the study.
Results
At three months, patients who received MSU care were more likely to achieve recovery without disability compared with patients who received standard management (53% versus 43%; adjusted pooled odds ratio=2.43; 95% confidence interval: 1.75, 3.35; p<0.01). The median time from symptom onset to tPA treatment was lower among patients receiving MSU care compared with those receiving standard management (72 versus 108 minutes; p=<0.001)
Patients receiving MSU care versus standard management did not differ significantly in quality of life, survival, or healthcare utilization.
Limitations
The study took place at seven urban locations across the United States. Results may differ in non-urban settings.
Conclusions and Relevance
In this study, patients receiving MSU treatment had a lower disability level and received treatment faster than patients receiving hospital-based treatment.
Future Research Needs
Future research could examine the effect of MSU treatment on patients in non-urban settings.
COVID-19-Related Study
Comparing Treatment for Stroke before and during the COVID-19 Pandemic
Results Summary
In response to the COVID-19 public health crisis in 2020, PCORI launched an initiative to enhance existing research projects so that they could offer findings related to COVID-19. The initiative funded this study and others.
What was this COVID-19 study about?
Strokes can cause serious disability or death. If patients receive treatment with medicine quickly, they may have a better recovery. A PCORI-funded study compared mobile stroke units, or MSUs, versus standard emergency room, or ER, care for patients having a stroke. MSUs are ambulances with special equipment and staff who can assess and treat people at the site of the 911 call. The study took place before and during the pandemic.
In this study, the research team wanted to see if changes to the way the team collected data during the pandemic affected the accuracy of the data.
The research team also wanted to learn if:
- Patients with strokes called for help less quickly and less often during the pandemic
- Patient traits differed before and during the pandemic
- MSU and ER quality of care differed before and during the pandemic
What were the results?
The accuracy of data collected in person before the pandemic and by phone during the pandemic didn’t differ.
Compared with before the pandemic, during the pandemic:
- The percent of patients who were eligible to receive medicine to treat strokes decreased, which may have been due to the fact that they didn’t call for help as quickly.
- MSUs spent an average of five minutes longer at the 911 site.
Before versus during the pandemic, the research team didn’t find a change in:
- The number of 911 calls for stroke
- Patient traits
- The time for an ambulance to arrive
- The time between MSU arrival to treatment
- The time before the patient got tests and treatment in the ER
Who was in the study?
The study included 926 adult patients who had had a stroke and were eligible to take medicine to treat it. All were enrolled at one of five sites across the United States. Of the 869 patients who received care before the pandemic, 55 percent were White, 38 percent were Black, 4 percent were Asian, 1 percent were American Indian or Alaska Native, and 1 percent were Native Hawaiian or Pacific Islander; 19 percent were Hispanic or Latino. The average age was 67, and 51 percent were women. The 57 patients who received care during the pandemic had similar traits.
What did the research team do?
Before the pandemic, the research team collected patient data in person three months after patients left the hospital. During the pandemic, the team collected these data by phone. To look at how well these methods worked, the team compared the data collected by both methods with data collected in person at the hospital before patients went home. The team also looked at how often patients called 911 for strokes, treatment times, and other study outcomes.
Stroke survivors, ambulance staff, health system administrators, and members of government and professional organizations helped design the study.
What were the limits of the study?
The study took place at five urban sites across the United States. Results may differ in rural areas.
How can people use the results?
Researchers can use these results when considering ways to adapt studies during public health crises.
Professional Abstract
In response to the COVID-19 public health crisis in 2020, PCORI launched an initiative to enhance existing research projects so that they could offer findings related to COVID-19. The initiative funded this study and others.
Background
A study comparing mobile stroke units (MSUs) versus usual care started before and continued during the COVID-19 pandemic. MSUs are ambulances with special equipment and staff who can diagnose and treat strokes on the scene. Due to pandemic-related safety reasons and data quality concerns, researchers had to change enrollment and data collection procedures, which provided an opportunity to examine changes in data collection and time to treatment metrics before versus during the pandemic.
Objective
To compare the following before versus during the pandemic among patients who have had a stroke: (1) accuracy of in-person versus remote data collection for assessing stroke-related outcomes; (2) patient characteristics and the number of stroke alerts; (3) MSU and emergency department (ED) treatment times
Study Design
| Design Element | Description |
|---|---|
| Design | Observational: cohort study |
| Population | 926 patients ages 18 and older who had had a stroke, were eligible for tPA treatment, and enrolled at 1 of 5 study sites across the United States |
| Outcomes | Objective 1: accuracy of data collection for disability level and quality of life outcomes (defined as the correlation between data collected in person at hospital discharge and data collected at 90 days, either in person before the pandemic or remotely during the pandemic) Objective 2: number of stroke alerts, number of patients eligible for tPA, and patient characteristics. Objective 3: MSU treatment time outcomes including time from 911 alert to MSU arrival on scene, time from MSU arrival on scene to departure, time from MSU arrival on scene to tPA treatment; ED treatment time outcomes including time from ED arrival to computed tomography scan, time from ED arrival to tPA treatment, and time from ED arrival to groin puncture |
| Data Collection Timeframe | May 2014–May 2021 |
This cohort study compared remote versus in-person data collection and time to treatment metrics before and during the pandemic for patients who received MSU-based treatment or standard management from emergency medical services (EMS).
The study included 926 patients who had had a stroke and were eligible for tissue plasminogen activator (tPA). Of the 869 patients receiving care before the pandemic, 55% were White, 38% were Black, 4% were Asian, 1% were American Indian or Alaska Native, and 1% were Native Hawaiian or Pacific Islander; 19% were Hispanic or Latino. The average age was 67, and 51% were female. Demographics for patients receiving care during the pandemic were similar.
To assess the accuracy of data collection before versus during the pandemic, researchers compared the correlation between stroke-related outcomes obtained in person at hospital discharge versus 90-day in-person or remote assessment. Researchers also collected data about the frequency of stroke calls, treatment eligibility, and MSU and ED treatment time metrics before and during the pandemic and compared other study outcomes.
Stroke survivors, EMS staff, health system administrators, and members of government and professional organizations helped design the study.
Results
After three months, accuracy of the 90-day assessment for disability and quality of life did not differ significantly between data collected in person before the pandemic versus data collected remotely during the pandemic.
Patient characteristics and number of stroke alerts did not differ significantly before versus during the pandemic. The percentage of screened and enrolled patients determined to be eligible for tPA declined during the pandemic from 13.6% to 6.6% (p<0.001).
Compared with before the pandemic, the MSU was on the scene with the patient five minutes longer during the pandemic (p<0.01). Other MSU and ED treatment times before and during the pandemic did not differ significantly.
Limitations
The study took place in five urban settings. Results may differ in other settings.
Conclusions and Relevance
In this study, remote data collection methods used in place of in-person data collection worked effectively during the pandemic; accuracy of assessments of stroke-related outcomes was not affected. Of note, fewer patients with acute stroke called 911 in time for tPA treatment during the pandemic. MSU on-scene time was slightly longer during COVID-19, but other MSU and EMS time-to-treatment metrics did not differ between the two periods.
Peer Review Summary
The Peer-Review Summary for this COVID-19 study will be posted here soon.
Final Enhancement Report
This COVID-19 study's final enhancement report is expected to be available by September 2024.
Final Research Report
This project's final research report is expected to be available by September 2024.
Journal Citations
Results of This Project
Related Journal Citations
Peer-Review Summary
Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.
The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments.
Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:
- The reviewers questioned how the researchers established the treatment groups for analysis. In the study, the standard management (SM) and mobile stroke unit (MSU) interventions were delivered on alternate days or weeks so that each intervention condition would include the same number of patients. However, the report states that 35 people assigned to the MSU intervention actually received SM intervention. Therefore, these 35 people were included in the SM group for the primary analyses, but in the MSU group for sensitivity analyses. The researchers explained that sometimes on MSU weeks the mobile van was not available, so some people received standard care and were counted in the SM group to help with recruitment numbers. The researchers assured the reviewers that these group assignment changes did not create added bias in the analyses.
- The reviewers noted that the better stroke outcomes for the MSU group over the SM group might not be because treatment with an intravenously administered thrombolytic occurred sooner. Another reason for this difference between groups could be attributed to more accurate treatment administration by MSU personnel, who were specially trained in the procedure, than by the SM personnel, who handled all manner of medical emergencies. The researchers agreed that speed and accuracy were factors in the better outcomes for patients treated by the MSU than for patients in SM.
- The reviewers asked about the clusters created by the timed administration of MSU and SM because differences between the groups could be accounted for by weekly clusters for treatment. The reviewers recommended that the researchers consider adding a variable to account for clustering to their analyses to account for this possible effect, but the researchers explained that they did not have the week cluster information in their database so they could not conduct additional analyses. The researchers did add this concern to their study limitations.