We evaluated whether carotid intima-media thickness (CIMT) and the presence or absence
of plaque improved coronary heart disease (CHD) risk prediction when added to traditional
risk factors (TRF).
Traditional CHD risk prediction schemes need further improvement as the majority of
the CHD events occur in the "low" and "intermediate" risk groups. On an ultrasound
scan, CIMT and presence of plaque are associated with CHD, and therefore could potentially
help improve CHD risk prediction.
Risk prediction models (overall, and in men and women) considered included TRF only,
TRF plus CIMT, TRF plus plaque, and TRF plus CIMT plus plaque. Model predictivity
was determined by calculating the area under the receiver-operating characteristic
curve (AUC) adjusted for optimism. Cox proportional hazards models were used to estimate
10-year CHD risk for each model, and the number of subjects reclassified was determined.
Observed events were compared with expected events, and the net reclassification index
was calculated.
Of 13,145 eligible subjects (5,682 men, 7,463 women), approximately 23% were reclassified
by adding CIMT plus plaque information. Overall, the CIMT plus TRF plus plaque model
provided the most improvement in AUC, which increased from 0.742 (TRF only) to 0.755
(95% confidence interval for the difference in adjusted AUC: 0.008 to 0.017) in the
overall sample. Similarly, the CIMT plus TRF plus plaque model had the best net reclassification
index of 9.9% in the overall population. Sex-specific analyses are presented in the
manuscript.
Adding plaque and CIMT to TRF improves CHD risk prediction in the ARIC (Atherosclerosis
Risk In Communities) study.
Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier
Inc. All rights reserved.