Cross-sectionally Assessed Carotid Intima-media Thickness Relates to Long-term Risk of Stroke, Coronary Heart Disease and Death As Estimated by Available Risk Functions

Objective: To relate cross-sectionally assessed indicators of carotid atherosclerosis measured in participants of the Rotterdam Study to absolute 10-12 year risks of stroke, coronary heart disease and death estimated by risk functions available from other studies.

Setting: General population living in the suburb of Ommoord in Rotterdam, The Netherlands.

Subjects: A sample of men and women (n = 1683), aged 55 years or over, drawn from participants from the Rotterdam Study (n = 7983).

Main Outcomes Measures: Three risk scores were used to estimate for each individual the absolute risk of stroke, coronary heart disease and death within 10-12 years as a function of their cardiovascular risk factor profile. Cross-sectionally measured indicators of carotid atherosclerosis (presence of atherosclerotic lesions and common carotid intima-media thickness) were subsequently related to these risk scores.

Results: The 10-year absolute risk of stroke increased linearly from 4.8% (95% CI = 3.8, 5.8) for subjects in the lowest quintile to 16.1% (12.3, 21.9) for subjects in the highest quintile of common carotid intima-media thickness distribution. Similarly, the 10-year absolute risk for coronary heart disease rose from 13.1% (95% CI = 12.0, 14.2) to 23.4% (95% CI = 21.4, 25.4), whereas the risk of death within 11.5 years rose from 15.0% (95% CI = 12.8, 17.4) in the lowest quintile to 46.0% (42.8, 49.3) in the upper quintile. The absolute risks of stroke, coronary heart disease or death rose from 8.8, 15.8 and 26.9% to 14.3, 19.8 and 40.9%, respectively, when plaques in the common carotid artery were present. Similar findings were observed for plaques in the carotid bifurcation.

Conclusion: Common carotid intima-media thickness and carotid plaques are markers for increased risk of stroke, coronary heart disease and death within 10-12 years.