Author + information
- Received July 13, 2009
- Revision received October 30, 2009
- Accepted November 2, 2009
- Published online April 13, 2010.
- Vijay Nambi, MD⁎,†,⁎ (, )
- Lloyd Chambless, PhD‡,
- Aaron R. Folsom, MD§,
- Max He, MS‡,
- Yijuan Hu, BS‡,
- Tom Mosley, PhD∥,
- Kelly Volcik, PhD¶,
- Eric Boerwinkle, PhD¶ and
- Christie M. Ballantyne, MD⁎,†
- ↵⁎Reprint requests and correspondence:
Dr. Vijay Nambi, Baylor College of Medicine, 6565 Fannin Street, STE-B 160/MS-A601, Houston, Texas 77030
Objectives 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).
Background 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.
Methods 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.
Results Of 13,145 eligible subjects (5,682 men, 7,463 women), ∼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.
Conclusions Adding plaque and CIMT to TRF improves CHD risk prediction in the ARIC (Atherosclerosis Risk In Communities) study.
The ARIC study is carried out as a collaborative study supported by National Heart, Lung, and Blood Institute (NHLBI)contracts N01-HC-55015, N01-HC-55016, N01-HC-55018, N01-HC-55019, N01-HC-55020, N01-HC-55021, and N01-HC-55022from the NHLBI, Bethesda, Maryland. Dr. Nambi has research collaboration with General Electric. Dr. Ballantyne is a consultant for Abbott, Astra Zeneca, Atherogenics, Bristol-Myers Squibb, KOWA, Metabsis, Merck, Merck-Schering-Plough, Novartis, Pfizer, Reliant, Schering-Plough, Sanofi-Synthelabo, Takeda, and GlaxoSmithKline; has received grant/research support from Abbott, ActivBiotics, AstraZeneca, Gene Logic, GlaxoSmithKline, Integrated Therapeutics, Merck, Pfizer, Schering-Plough, Sanofi-Synthelabo, and Takeda; is on the Speakers’ Bureau for AstraZeneca, GlaxoSmithKline, Merck, Pfizer, Reliant, and Merck-Schering-Plough, Schering-Plough; and has received honorarium from Merck, AstraZeneca, Abbott, GlaxoSmithKline, Merck-Schering-Plough, Novartis, Pfizer, Sanof-Synthelabo, Schering-Plough, and Takeda.
- Received July 13, 2009.
- Revision received October 30, 2009.
- Accepted November 2, 2009.
- American College of Cardiology Foundation