Abstract 3224: Reasons for Disability after “Mild” Ischemic Strokes: A Retrospective, Exploratory Analysis

Abstract

BACKGROUND: Prior studies have reported that approximately one-third of patients with strokes perceived as mild at onset and not treated with IV rtPA have significant disability at three months. Disability after stroke in this setting could be due to: (1) the initial stroke event, including its early progression, (2) stroke recurrence, or (3) other medical events related to medical comorbidities. We sought to explore these three potential reasons for disability among mild ischemic stroke subjects in a longitudinal study of stroke outcomes in consideration of planning a large-scale randomized trial of acute intervention. METHODS: During 2005, a convenience sample of 460 ischemic stroke patients was drawn from a population-based cohort and prospectively recruited. Clinical characteristics were obtained by detailed chart abstractions, and in-person or phone interviews at three months. NIHSS scores at stroke onset were determined retrospectively by chart review using validated methods. This analysis was limited to mild stroke patients (NIHSS 5 or less), with no prior disability (mRS 0-1), not treated with IV rtPA, and with three-month outcome data. We prespecified groups of characteristics potentially associated with each of the three reasons for disability after mild stroke as shown in the Table . We also reviewed unstructured patient accounts of reasons for disability at their 90-day interviews. RESULTS: Among 460 patients, 291 (63%) were considered mild at onset; 96 with prior disability, 2 with IV rtPA treatment, and 17 missing all three-month outcome data were excluded. Among the remaining 176 patients, 95 (54%) had poor outcomes (mRS 2-6) at three months: 53% mRS2, 33% mRS 3, 9% mRS 4, 2% mRS 5, 3% mRS 6 (dead). Characteristics of those with disability at three months, compared to those without disability, are shown in the table below. Upon reviewing interview notes by study nurses containing self-reported descriptions of 90-day disability, 55 of 95 (58%) disabled patients attributed their disability to focal neurological dysfunction, and an additional 30 (31%) attributed it to unspecified gait difficulties. CONCLUSIONS: A substantial portion of disability may be due to the incident stroke event. Stroke recurrence and other medical comorbidities likely play a role in the 90-day disability rates of this patient population as well. This study is limited by its exploratory and retrospective nature. Large-scale prospective data in the setting of a randomized trial of an intervention is justified.