Comparison of Mobile Stroke Unit With Usual Care for Acute Ischemic Stroke Management: A Systematic Review and Meta-analysis

Abstract

Importance: So far, uncertainty remains as to whether there is sufficient cumulative evidence that mobile stroke unit (MSU; specialized ambulance equipped with computed tomography scanner, point-of-care laboratory, and neurological expertise) use leads to better functional outcomes compared with usual care.

Objective: To determine with a systematic review and meta-analysis of the literature whether MSU use is associated with better functional outcomes in patients with acute ischemic stroke (AIS).

Data sources: MEDLINE, Cochrane Library, and Embase from 1960 to 2021.

Study selection: Studies comparing MSU deployment and usual care for patients with suspected stroke were eligible for analysis, excluding case series and case-control studies.

Data extraction and synthesis: Independent data extraction by 2 observers, following the PRISMA and MOOSE reporting guidelines. The risk of bias in each study was determined using the ROBINS-I and RoB2 tools. In the case of articles with partially overlapping study populations, unpublished disentangled results were obtained. Data were pooled in random-effects meta-analyses.

Main outcomes and measures: The primary outcome was excellent outcome as measured with the modified Rankin Scale (mRS; score of 0 to 1 at 90 days).

Results: Compared with usual care, MSU use was associated with excellent outcome (adjusted odds ratio [OR], 1.64; 95% CI, 1.27-2.13; P < .001; 5 studies; n = 3228), reduced disability over the full range of the mRS (adjusted common OR, 1.39; 95% CI, 1.14-1.70; P = .001; 3 studies; n = 1563), good outcome (mRS score of 0 to 2: crude OR, 1.25; 95% CI, 1.09-1.44; P = .001; 6 studies; n = 3266), shorter onset-to-intravenous thrombolysis (IVT) times (median reduction, 31 minutes [95% CI, 23-39]; P < .001; 13 studies; n = 3322), delivery of IVT (crude OR, 1.83; 95% CI, 1.58-2.12; P < .001; 7 studies; n = 4790), and IVT within 60 minutes of symptom onset (crude OR, 7.71; 95% CI, 4.17-14.25; P < .001; 8 studies; n = 3351). MSU use was not associated with an increased risk of all-cause mortality at 7 days or at 90 days or with higher proportions of symptomatic intracranial hemorrhage after IVT.

Conclusions and relevance: Compared with usual care, MSU use was associated with an approximately 65% increase in the odds of excellent outcome and a 30-minute reduction in onset-to-IVT times, without safety concerns. These results should help guideline writing committees and policy makers.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Turc is an investigator of the ASPHALT project and has received personal fees from Guerbet France. Dr Hadziahmetovic is an investigator of the ASPHALT project. Dr Larsen is an investigator of the Treat-NASPP study and a board member of the PRE-hospital Stroke Treatment Organization (PRESTO). Dr Grotta has received grants from Genentech and CSL Behring as well as personal fees from Frazer Ltd and Haemonetics. Dr Zhao has received grants from Australian Commonwealth Government and the University of Melbourne. Dr Uchino is a clinical end point adjudication committee member for Abbott Laboratories. Dr Weber has received research grants from German Ministry of Research and Education and was an investigator of the PHANTOM-S randomized trial and the B_PROUD study. Dr Nolte has received grants from Deutsche Forschungsgemeinschaft, German Ministry of Research and Education, German Center for Neurodegenerative Diseases, and German Center for Cardiovascular Research as well as personal fees from Abbott, Alexion, Boehringer Ingelheim, Bristol Myers Squibb, Bayer, Daiichi Sankyo, and Pfizer. Dr Sacco has received personal fees from Allergan, Abbott, Eli Lilly, Novo Nordisk, AstraZeneca, Novartis, Teva, and Lundbeck as well as grants from Novartis and Allergan. Dr Audebert has received grants from Deutsche Forschungsgemeinschaft and German Federal Ministry of Education and Research; personal fees from Boehringer Ingelheim, Bayer Vital, Bristol Myers Squibb, Novo Nordisk, Pfizer, Sanofi, and AstraZeneca; is an investigator of the PHANTOM-S randomized trial and the B_PROUD study; and is President of the Prehospital Stroke Treatment Organization (PRESTO). No other disclosures were reported.

Figures

Figure 1.. Pooled Adjusted Odds Ratio (OR) for Excellent Outcome at 90 Days (Modified Rankin Scale Score of 0 to 1) in Patients With Mobile Stroke Unit (MSU) Deployment vs Usual Care (Random-Effects Meta-analysis)

Results are expressed as number of patients with a modified Rankin Scale score of 0 to 1 divided by the total number of patients in each treatment group. Adjustment variables differed across studies (eTable 2 in the Supplement). The test for heterogeneity between subgroups was P = .39. NA indicates not applicable. aPreviously unpublished data, excluding patients with stroke mimic in the study by Larsen et al. When including patients with stroke mimic, the adjusted OR for excellent outcome in the study by Larsen et al was 1.45 (95% CI, 0.60-3.51). Results from Helwig et al correspond to a post hoc analysis based on individual participant data, with adjustment on age and baseline National Institutes of Health Stroke Scale score.

Figure 2.. Pooled Crude Odds Ratio (OR) Associated With the Proportions of Intravenous Thrombolysis Among Patients With Acute Ischemic Stroke According to Treatment Group (Mobile Stroke Unit [MSU] Deployment vs Usual Care, Random-Effects Meta-analysis)

Results are expressed as number of patients treated with intravenous thrombolysis divided by the number of patients with acute ischemic stroke in each treatment group. The test for heterogeneity between subgroups was P = .98. aPreviously unpublished data, excluding patients with stroke mimic in the study by Larsen et al.

Figure 3.. Pooled Crude Odds Ratio (OR) Associated With the Proportions of Golden-Hour Intravenous Thrombolysis According to Treatment Group (Mobile Stroke Unit [MSU] Deployment vs Usual Care, Random-Effects Meta-analysis)

Results are expressed as number of patients treated with intravenous thrombolysis within 60 minutes of symptom onset divided by number of patients treated with intravenous thrombolysis in each treatment group. The test for heterogeneity between subgroups was P = .08. NA indicates not applicable. aPreviously unpublished (disentangled) data, excluding patients with stroke mimic in the study by Larsen et al. When including patients with stroke mimic, the crude OR for golden-hour thrombolysis in the study by Larsen et al was 4.62 (95% CI, 1.46-14.59). Furthermore, there was partial overlap in participants between the studies by Ebinger et al, Kunz et al, and Nolte et al.

Figure 4.. Pooled Difference of Medians of Time From Symptom Onset or Last Known Well to Intravenous Thrombolysis in Patients With Mobile Stroke Unit (MSU) Deployment vs Usual Care (Random-Effects Meta-analysis)

The test for heterogeneity between subgroups was P = .48. aPreviously unpublished (disentangled) data. There was partial overlap in participants between the PHANTOM-S study and the study by Kunz et al. bEstimated from published mean (SD) values (101 [46] minutes vs 144 [50] minutes), assuming normal distribution.