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Piccininni M, Kurth T, Audebert HJ, Rohmann JL. The Effect of Mobile Stroke Unit Care on Functional Outcomes: An Application of the Front-door Formula. Epidemiology 2023; 34:712-720. [PMID: 37462471 DOI: 10.1097/ede.0000000000001642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
BACKGROUND The Berlin-based B_PROUD study was designed to assess the effect of mobile stroke unit (MSU) dispatch among ischemic stroke and transient ischemic attack (TIA) patients without contraindications to reperfusion treatments. However, a large proportion of patients for whom the MSU was dispatched did not ultimately receive MSU care. We estimated the causal effect of additional MSU care on 3-month functional outcomes among B_PROUD patients for whom an MSU was dispatched. METHODS We used data from the B_PROUD study (1 February 2017-8 May 2019). Given the presence of exposure-outcome unmeasured confounding, we used the front-door formula to identify the distribution of modified Rankin scale (mRS) outcomes under two hypothetical interventions: (1) receiving additional MSU care and (2) only receiving conventional care. We considered the time from dispatch to thrombolysis as the full mediator and adjusted for exposure-mediator and mediator-outcome confounding. We used a parametric estimator to estimate the common odds ratio (cOR) and 95% bootstrapped confidence intervals (CI). RESULTS We included in total 768 ischemic stroke/TIA patients with MSU dispatch. The MSU was canceled for 180 (23%) patients, whereas 588 (77%) received MSU care. The unadjusted association between the care group and mRS favored conventional care (cOR = 1.7; 95% CI = 1.2, 2.3); however, after applying the front-door formula, the mRS distribution favored MSU care (cOR = 0.88; 95% CI = 0.81, 0.96). CONCLUSIONS Receiving MSU care was associated with better functional outcomes than conventional care only, compatible with the hypothesized beneficial effect of MSU care on poststroke outcomes, among stroke and TIA patients without contraindications to reperfusion treatments.
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Affiliation(s)
- Marco Piccininni
- From the Institute of Public Health, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tobias Kurth
- From the Institute of Public Health, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Heinrich J Audebert
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jessica L Rohmann
- From the Institute of Public Health, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Rohmann JL, Huerta-Gutierrez R, Audebert HJ, Kurth T, Piccininni M. Adjusted horizontal stacked bar graphs (“Grotta bars”) for consistent presentation of observational stroke study results. Eur Stroke J 2023; 8:370-379. [PMID: 37021164 PMCID: PMC10069225 DOI: 10.1177/23969873221149464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/16/2022] [Indexed: 01/15/2023] Open
Abstract
Background: Modified Rankin Scale (mRS) scores are used to measure functional outcomes after stroke. Researchers create horizontal stacked bar graphs (nicknamed “Grotta bars”) to illustrate distributional differences in scores between groups. In well-conducted randomized controlled trials, Grotta bars have a causal interpretation. However, the common practice of exclusively presenting unadjusted Grotta bars in observational studies can be misleading in the presence of confounding. We demonstrated this problem and a possible solution using an empirical comparison of 3-month mRS scores among stroke/TIA patients discharged home versus elsewhere after hospitalization. Patients and methods: Using data from the Berlin-based B-SPATIAL registry, we estimated the probability of being discharged home conditional on prespecified measured confounding factors and generated stabilized inverse probability of treatment (IPT) weights for each patient. We visualized mRS distributions by group with Grotta bars for the IPT-weighted population in which measured confounding was removed. We then used ordinal logistic regression to quantify unadjusted and adjusted associations between being discharged home and the 3-month mRS score. Results: Of 3184 eligible patients, 2537 (79.7%) were discharged home. In the unadjusted analyses, those discharged home had considerably lower mRS compared with patients discharged elsewhere (common odds ratio, cOR = 0.13, 95% CI: 0.11–0.15). After removing measured confounding, we obtained substantially different mRS distributions, visually apparent in the adjusted Grotta bars. No statistically significant association was found after confounding adjustment (cOR = 0.82, 95% CI: 0.60–1.12). Discussion and conclusion: The practice of presenting only unadjusted stacked bar graphs for mRS scores together with adjusted effect estimates in observational studies can be misleading. IPT weighting can be implemented to create Grotta bars that account for measured confounding, which are more consistent with the presentation of adjusted results in observational studies.
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Affiliation(s)
- Jessica L Rohmann
- Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Institute of Public Health, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Rodrigo Huerta-Gutierrez
- Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Institute of Public Health, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Heinrich J Audebert
- Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Klinik und Hochschulambulanz für Neurologie, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Tobias Kurth
- Institute of Public Health, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Marco Piccininni
- Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Institute of Public Health, Charité – Universitätsmedizin Berlin, Berlin, Germany
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Rohmann JL, Piccininni M, Ebinger M, Wendt M, Weber JE, Schwabauer E, Geisler F, Freitag E, Harmel P, Lorenz-Meyer I, Rohrpasser-Napierkowski I, Nolte CH, Nabavi DG, Schmehl I, Ekkernkamp A, Endres M, Audebert HJ. Effect of Mobile Stroke Unit Dispatch in all Patients with Acute Stroke or TIA. Ann Neurol 2023; 93:50-63. [PMID: 36309933 DOI: 10.1002/ana.26541] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/28/2022] [Accepted: 10/28/2022] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To determine the effect of additional mobile stroke unit (MSU) dispatch on functional outcomes among the full spectrum of stroke patients, regardless of subtype or potential contraindications to reperfusion therapies. METHODS We used data from the nonrandomized Berlin-based B_PROUD study (02/2017 to 05/2019), in which MSUs were dispatched based solely on availability, and the linked B-SPATIAL stroke registry. All patients with final stroke or transient ischemic attack (TIA) diagnoses were eligible. The intervention under study was the additional dispatch of an MSU, an emergency physician-staffed ambulance equipped to provide prehospital imaging and thrombolytic treatment, compared to conventional ambulance alone. The primary outcome was the 3-month modified Rankin Scale (mRS) score, and the co-primary outcome was a 3-tiered disability scale. We identified confounders using directed acyclic graphs and obtained adjusted effect estimates using inverse probability of treatment weighting. RESULTS MSUs were dispatched to 1,125 patients (mean age: 74 years, 46.5% female), while for 1,141 patients only conventional ambulances were dispatched (75 years, 49.9% female). After confounding adjustment, MSU dispatch was associated with more favorable 3-month mRS scores (common odds ratio [cOR] = 0.82; 95% confidence interval [CI]: 0.71-0.94). No statistically significant association was found with the co-primary outcome (cOR = 0.86; 9% CI: 0.72-1.01) or 7-day mortality (OR = 0.94; 95% CI: 0.59-1.48). INTERPRETATION When considering the entire population of stroke/TIA patients, MSU dispatch improved 3-month functional outcomes without evidence of compromised safety. Our results are relevant for decision-makers since stroke subtype and treatment eligibility are unknown at time of dispatch. ANN NEUROL 2023;93:50-63.
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Affiliation(s)
- Jessica L Rohmann
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Institute of Public Health, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marco Piccininni
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Institute of Public Health, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Martin Ebinger
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Klinik für Neurologie, Medical Park Berlin (MPB) Humboldtmühle, Berlin, Germany
| | - Matthias Wendt
- Klinik für Neurologie mit Stroke Unit und Frührehabilitation, Unfallkrankenhaus Berlin, Berlin, Germany
| | - Joachim E Weber
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Eugen Schwabauer
- Klinik für Neurologie mit Stroke Unit, Vivantes Klinikum Neukölln, Berlin, Germany
| | - Frederik Geisler
- Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Erik Freitag
- Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Harmel
- Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Irina Lorenz-Meyer
- Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Christian H Nolte
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Darius G Nabavi
- Klinik für Neurologie mit Stroke Unit, Vivantes Klinikum Neukölln, Berlin, Germany
| | - Ingo Schmehl
- Klinik für Neurologie mit Stroke Unit und Frührehabilitation, Unfallkrankenhaus Berlin, Berlin, Germany
| | | | - Matthias Endres
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Centre for Cardiovascular Research (DZHK), Berlin, Germany.,NeuroCure Cluster of Excellence, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Heinrich J Audebert
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Ge C, Muehlschlegel S. The Opt-Out Approach in Research to Benefit Public Health: Is "Opting Out" In? Neurology 2022; 99:545-546. [PMID: 35918159 DOI: 10.1212/wnl.0000000000201108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/29/2022] [Indexed: 11/15/2022] Open
Affiliation(s)
- Connie Ge
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA
| | - Susanne Muehlschlegel
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA .,Department of Anesthesiology/Critical Care, University of Massachusetts Chan Medical School, Worcester, MA.,Department of Surgery, University of Massachusetts Chan Medical School, Worcester, MA
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