Age Accounts for Racial Differences in Ischemic Stroke Volume in a Population-Based Study

Abstract

Background: The stroke volume among black ischemic stroke patients in phase I of the population-based Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS) was smaller than reported among acute stroke studies, with a median stroke volume of 2.5 cm. However, it is not known if stroke volume was similar between black and white patients within the same study population. Methods: Phase II of the GCNKSS identified all ischemic strokes between July 1993 and June 1994. The stroke volume was estimated by study physicians using the modified ellipsoid method. Analysis of stroke volume by race, sex and age was performed for strokes with a measurable lesion of ≧0.5 cm³. Results: Among verified cases of ischemic stroke, 334 patients were eligible for this analysis. There were 191 whites (57%) and 143 blacks (43%). The mean age was 69.4 years. The median stroke volume for all patients was 8.8 cm³ (range 0.5–540), with a mean of 36.4 cm³. Stroke volume was not different between men and women, and it tended to increase with age. Although stroke volume was significantly higher among whites, age was a confounding factor. Subsequent analysis of stroke volume stratified by age showed no difference between blacks and whites in any age group. Conclusions: Our data show that most ischemic stroke lesions, regardless of the race, are of small size, and this may be an important reason for the low percentageof strokes treated currently with tissue-type plasminogen activator. The association of age with stroke volume requires further study.