Outcomes of patients with pre-existing disability managed by mobile stroke units: A sub-analysis of the BEST-MSU study

Abstract

Background: Few data exist on acute stroke treatment in previously disabled (PD) patients since they are usually excluded from clinical trials. A recent trial of Mobile Stroke Units (MSUs) demonstrated faster treatment and improved outcomes, and included PD patients. Aim: Determine outcomes with tissue plasminogen activator (tPA), and benefit of MSU versus management by emergency medical services (EMS), for PD patients. Methods: Primary outcomes were utility-weighted modified Rankin Score (uw-mRS). Linear and logistic regression models compared outcomes in patients with vs without PD, and PD patients treated by MSU vs standard management by emergency medical services (EMS). Time metrics, safety, quality of life, and health-care utilization were compared. Results: 1047 tPA-eligible ischemic stroke patients; 254 with PD (baseline mRS 2-5), and 793 without PD (baseline mRS 0-1). Although PD patients had worse 90-day uw-mRS, higher mortality, more health-care utilization and worse quality-of-life than non-disabled patients, 53% returned to at least their baseline mRS, those treated faster had better outcome, and there was no increased bleeding risk. Comparing PD patients treated by MSU versus EMS, 90-day uw-mRS was 0.42 versus 0.36 (p=0.07) and 57% versus 46% returned to at least their baseline mRS. There was no interaction between disability status and MSU versus EMS group assignment (p=0.67), for 90-day uw-mRS. Conclusion: Pre-existing disability did not prevent the benefit of faster treatment with tPA on a MSU. Our data support inclusion of PD patients in the MSU management paradigm.