Association between dispatch of mobile stroke units and functional outcomes among patients with acute ischemic stroke in Berlin

Importance Effects of thrombolysis in acute ischemic stroke are time-dependent. Ambulances that can administer thrombolysis (mobile stroke units [MSUs]) before arriving at the hospital have been shown to reduce time to treatment. Objective To determine whether dispatch of MSUs is associated with better clinical outcomes for patients with acute ischemic stroke. Design, Setting, and Participants This prospective, nonrandomized, controlled intervention study was conducted in Berlin, Germany, from February 1, 2017, to October 30, 2019. If an emergency call prompted suspicion of stroke, both a conventional ambulance and an MSU, when available, were dispatched. Functional outcomes of patients with final diagnosis of acute cerebral ischemia who were eligible for thrombolysis or thrombectomy were compared based on the initial dispatch (both MSU and conventional ambulance or conventional ambulance only). Exposure Simultaneous dispatch of an MSU (computed tomographic scanning with or without angiography, point-of-care laboratory testing, and thrombolysis capabilities on board) and a conventional ambulance (n = 749) vs conventional ambulance alone (n = 794). Main Outcomes and Measures The primary outcome was the distribution of modified Rankin Scale (mRS) scores (a disability score ranging from 0, no neurological deficits, to 6, death) at 3 months. The coprimary outcome was a 3-tier disability scale at 3 months (none to moderate disability; severe disability; death) with tier assignment based on mRS scores if available or place of residence if mRS scores were not available. Common odds ratios (ORs) were used to quantify the association between exposure and outcome; values less than 1.00 indicated a favorable shift in the mRS distribution and lower odds of higher levels of disability. Results Of the 1543 patients (mean age, 74 years; 723 women [47%]) included in the adjusted primary analysis, 1337 (87%) had available mRS scores (primary outcome) and 1506 patients (98%) had available the 3-tier disability scale assessment (coprimary outcome). Patients with an MSU dispatched had lower median mRS scores at month 3 (1; interquartile range [IQR], 0-3) than did patients without an MSU dispatched (2; IQR, 0-3; common OR for worse mRS, 0.71; 95% CI, 0.58-0.86; P < .001). Similarly, patients with an MSU dispatched had lower 3-month coprimary disability scores: 586 patients (80.3%) had none to moderate disability; 92 (12.6%) had severe disability; and 52 (7.1%) had died vs patients without an MSU dispatched: 605 (78.0%) had none to moderate disability; 103 (13.3%) had severe disability; and 68 (8.8%) had died (common OR for worse functional outcome, 0.73, 95% CI, 0.54-0.99; P = .04). Conclusions and Relevance In this prospective, nonrandomized, controlled intervention study of patients with acute ischemic stroke in Berlin, Germany, the dispatch of mobile stroke units, compared with conventional ambulances alone, was significantly associated with lower global disability at 3 months. Clinical trials in other regions are warranted.This cohort study compares global disability at 3 months among Berlin patients with out-of-hospital ischemic stroke brought to care via a mobile stroke unit ambulance (with prehospital CT scanning with or without angiography, point-of-care laboratory testing, prehospital thrombolysis) vs conventional ambulance alone.Question Is the dispatch of mobile stroke units in the out-of-hospital setting before arriving at the hospital associated with better functional outcomes among patients with acute ischemic stroke eligible for thrombolysis or thrombectomy? Findings In this prospective nonrandomized controlled intervention study involving 1543 patients in Berlin, Germany, the dispatch of mobile stroke units in addition to conventional ambulances vs conventional ambulances alone was significantly associated with lower levels of global disability at 3 months (common odds ratio for higher modified Rankin Scale scores [ie, worse outcome], 0.71). Meaning Among patients with acute ischemic stroke in Berlin, Germany, dispatch of a mobile stroke unit was associated with lower global disability at 3 months; further research in diverse settings is needed.Clinical epidemiolog

Follow-up of patients with stroke based on opt-out choice: potential approach for acute care quality registries or observational studies

Background and Objectives: Restricting follow-up assessment of both interventional and observational studies to patients who provide informed consent introduces relevant selection bias-particularly by underrepresenting patients with neurologic communication deficits and impaired capacity to consent. Many patients who are initially unable to give consentmay be willing to do so after recovery. Informing patients on study purposes and procedures with offering them the option of nonparticipation but not requesting explicit consent is called "opt-out" approach. We investigated whether an opt-out strategy yields meaningful follow-up rates in an acute stroke registry with an embedded controlled study. Methods: The citywide Berlin-SPecific Acute Treatment in Ischemic or hAemorrhagic Stroke With Long Term Follow-up (B-SPATIAL) registry was designed to provide reliable information on process indicators and outcomes of specific acute stroke treatments to inform health care providers about quality of care and best practice strategies including the effects of a mobile stroke unit implementation. Because this information was regarded of high public interest, Berlin data protection authorities permitted data sampling without prior informed consent, using instead follow-up assessment on an "opt-out" basis. Patients were included if they had neurologic symptoms at ambulance or hospital arrival within 6 hours of onset and had a final diagnosis of stroke or TIA. Information on data collection and outcome assessment was sent by letter to patients 1 month before follow-up. Results: From February 1, 2017, to January 31, 2020, a total of 10,597 patients were assessed. Thirty-one (0.3%) patients declined any data use, whereas 578 (5.5%) opted out of follow-up assessment. Of those not opting out (n = 9,988), functional outcome (modified Rankin Scale) was collected in 8,330 patients (83.4%) and vital status in 9,741 patients (97.5%). We received no complaints regarding data collection procedures. Discussion: Opt-out-based follow-up collection offers a way to achieve high follow-up rates along with respecting patients' preferences.</p