Long-term health benefits and costs of measurement of carotid intima-media thickness in prevention of coronary heart disease

Objective: Recently, it was demonstrated that information on carotid intima-media thickness (CIMT) and plaque may improve coronary heart disease (CHD) risk prediction through reclassification of some individuals to the correct risk category using the Framingham risk score. Our objective was to assess the currently unknown cost-effectiveness of CIMT measurements in primary prevention.

Methods: A hypothetical cohort of men and women aged 50-59 years and at intermediate or high CHD risk based on data from the Atherosclerosis Risk in Communities Study was simulated using a Markov model. Myocardial infarction (MI) events were used as a proxy for CHD. The effectiveness of pharmaceutical treatment was varied in the analysis. Sensitivity analysis was performed to obtain robust results.

Results: CIMT-based reclassification induced a 1% lower absolute risk of MI and 0.01-0.02 increase in quality-adjusted life years (QALYs) for men, and a 1-3% lower risk, and 0.03-0.05 increase in QALYs for women, over a period of 20-30 years. Corresponding costs were an additional $100 per man, and a cost-saving of $200-300 per woman. Over a 10-year period CIMT measurements were cost-effective with a probability of 66% (men), and 94% (women). Over a 30-year period, CIMT measurements had acceptable cost-effectiveness for men and women.

Conclusion: Performing CIMT measurements in asymptomatic men and women aged 50-59 years results in additional, but small, health benefits. It takes time for these health benefits to outweigh the initial CIMT measurement costs. Our results support CIMT measurements for cardiovascular risk stratification, in particular for women, when focusing on long-term health.