Prospective Evaluation of Carotid Bruit as a Predictor of First Stroke in Type 2 Diabetes

Abstract

Background and Purpose— We sought to examine prospectively the relationship between asymptomatic carotid bruit and stroke in type 2 diabetes. Methods— We studied 1181 (91.3%) of a community-based sample of 1294 patients with type 2 diabetes. These patients had no history of cerebrovascular disease at recruitment during 1993–1996 and were followed until the end of January 2002. Hospital morbidity and death register data relating to cerebrovascular events were also available. Cox proportional hazards models were used to determine whether carotid bruit status was an independent predictor of stroke and to identify other significant cerebrovascular risk factors. Results— One hundred thirty-four patients (11.3%) suffered a first stroke during 6.5±2.2 (mean±SD) years of follow-up. In the first 2 years after study entry, first stroke (n=45/1181; 3.8%) was strongly predicted by the presence of carotid bruit(s) after adjustment for known cardiovascular risk factors and other potentially confounding variables (hazard ratio, 6.7; 95% CI, 3.0 to 14.9; P <0.001). Between 2 years and census, first stroke (n=89/1083; 8.2%) was not associated with carotid bruit(s) ( P =0.97). Age and diastolic blood pressure were other determinants of stroke in the first 2 years, while age, atrial fibrillation/flutter, and microalbuminuria were independent predictors of subsequent stroke. Conclusions— Type 2 diabetic patients found to have incidental carotid bruits have >6 times the risk of first stroke in the first 2 years than patients without a bruit and should receive intensified management of vascular risk factors. Carotid imaging with a view to surgical intervention in these patients remains controversial.