Objective: To identify determinants of recurrence and mortality after ischemic stroke in a mixed-ethnic region.
Background: The determinants of ischemic stroke outcome are not uniformly characterized and will be of increasing importance as the frequency of ischemic stroke survivors increases in our aging population.
Methods: A cohort of 323 patients (40% black, 34% Hispanic, 26% white) with cerebral infarction from northern Manhattan over age 39 were followed for a mean of 3.3 years, with only 6% lost to follow-up. Cumulative life table risk of mortality and recurrence was calculated. Risk factors classified at the time of index ischemic stroke were selected based on univariate analyses and then entered into a Cox proportional hazards model for mortality and for recurrence.
Results: The life table cumulative risk of mortality was 8% at 30 days, 22% at 1 year, and 45% at 5 years after ischemic stroke. The immediate cause of death was related to vascular disease in 60%. After age adjustment, the significant predictors of mortality were congestive heart failure (risk ratio [RR] = 2.6), admission glucose > 140 mg/dl (RR = 1.7), and presentation with either a large dominant, nondominant, or major basilar syndrome (RR = 2.0). Patients with a lacunar syndrome had a better survival (RR = 0.6). Recurrent strokes occurred in 72 patients. The life table cumulative risk of recurrence was 6% at 30 days, 12% at 1 year, and 25% at 5 years after ischemic stroke. Ethanol abuse (RR = 2.5), hypertension requiring discharge medications (RR = 1.6), and elevated blood glucose within 48 hours of index ischemic stroke (RR = 1.2 per 50 mg/dl) were the independent predictors of recurrence. Among 30-day survivors, the effect of ethanol abuse was greater (RR = 3.5), indicating its impact on late recurrence.
Conclusions: After accounting for age and presenting syndrome, initial glucose predicts stroke mortality and recurrence after ischemic stroke. This association may reflect uncontrolled and undiagnosed diabetes in our urban population. Furthermore, ethanol abuse may be a determinant of ischemic stroke recurrence. Reduction of the stroke public health burden will require targeted modification of such conditions and behaviors.