Abstract 3131: Impact of Undetermined or Other Determined Categories by TOAST on Prognosis After Ischemic Stroke

Abstract

Background: A few studies have suggested that stroke subtypes influence the long-term mortality following ischemic stroke. However, the outcome in patients with strokes of undetermined or other determined etiology (OD) has not yet been elucidated. Method: We prospectively enrolled acute ischemic stroke and transient ischemic attack patients from 29 hospitals in Korea over a 9-year period. The Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria was used to classify stroke subtype. Stroke of undetermined etiology was further divided into 1) 2 or more cause, 2) negative etiology, and 3) incomplete evaluation (UI). We analyzed the demographics, risk factors, duration of admission, functional outcomes at discharge, 30-day mortality, and any cause mortality after stroke. Results: A total of 38,875 patients with ischemic stroke and transient ischemic attack were included in this study. Thirty-day mortality was 3.8%, and overall mortality at the end of follow-up was 23.2%. Mean follow-up duration was 1032±780 days. Thirty-day mortality and long-term mortality was highest in UI group (14.9% and 41.4%, respectively) among all stroke subtypes. The OD and UI subtype was a powerful predictor of 30-day mortality [for OD: odds ratio (OR) 2.18, 95% confidence interval (CI) 1.37-3.47; for UI: OR 3.30, 95% CI 2.65-4.10; large-artery atherosclerosis as a reference] after control of all possible confounders. In addition, the OD and UI subtype was an independent predictor of death during the follow-up [for OD: hazard ratio (HR) 1.81, 95% CI 1.49-2.20; for UI: HR 1.59, 95% CI 1.45-1.74; large-artery atherosclerosis as a reference]. Other independent predictors of long-term mortality were age, sex, body mass index, history of prior stroke, diabetes, dyslipidemia, NIHSS on admission, intrahospital treatment of thrombolytics, and second preventive medication at discharge. Conclusion: Our study on subgroups of undetermined and other determined etiology showed heterogenous prognosis.