Incremental Predictive Value of Carotid Ultrasonography in the Assessment of Coronary Risk in a Cohort of Asymptomatic Type 2 Diabetic Subjects

Abstract

OBJECTIVE —Consensus guidelines recommend cardiovascular risk assessment as the initial step of primary prevention. The aim of this study was to evaluate the incremental predictive value for coronary events conferred by carotid ultrasonography in addition to risk assessment by Framingham score and screening for silent myocardial ischemia in a cohort of type 2 diabetic patients. RESEARCH DESIGN AND METHODS —We prospectively studied 229 patients free of any cardiovascular complication with at least one additional cardiovascular risk factor. At baseline, all patients had an exercise treadmill test, carotid intima-media thickness (IMT) measurement, and coronary risk assessment by Framingham score. Cardiovascular events were registered during a 5-year follow-up period. RESULTS —Age, carotid IMT, carotid plaques, number of risk factors, Framingham score, and suboptimal exercise electrocardiogram were associated with incident cardiovascular events (P < 0.05). Carotid IMT was an independent predictor of cardiovascular events (P = 0.045). The predictive value for coronary events was similar for carotid IMT and Framingham score as assessed by area under the receiver operating characteristic curves. An improvement in risk prediction was conferred by addition of carotid IMT in a Cox model (global χ2 increased from 14.1 to 18.1, P = 0.035). CONCLUSIONS —This prospective study confirms that carotid IMT is a marker of cardiovascular risk in this type 2 diabetic cohort, establishes that carotid IMT provides a similar predictive value for coronary events than Framingham score, and suggests that the combination of these two indexes significantly improves risk prediction for these patients.