CAC improves CHD risk stratification metabolic syndrome, diabetic patients
MedWire News: Coronary artery calcium (CAC) screening may improve coronary heart disease (CHD) risk stratification in individuals with the metabolic syndrome and diabetes, suggests an analysis of the MESA cohort.
The study also shows that individuals with the metabolic syndrome or diabetes have a low risk for CHD when CAC or coronary intima-media thickness (cIMT) is not increased.
These findings support the current "appropriateness use criteria" for cardiac computed tomography, which recommends using CAC when assessing cardiovascular disease (CVD) risk in asymptomatic adults, including those with diabetes aged 40 years or older, explain Nathan Wong (University of California-Irvine, USA) and co-authors in the journal Diabetes Care.
The researchers assessed CAC and cIMT in 6603 participants of the MESA (Multi-Ethnic Study of Atherosclerosis) study, who were aged 45-84 years. Of these, 13% (n=881) had diabetes and 26% (n=1686) had the metabolic syndrome without diabetes. During 6.4 years of follow-up a total of 299 CHD and 410 CVD events occurred.
Annual CHD event rates for those with the metabolic syndrome, diabetes, or neither condition were low, at 1.0%, 1.5%, and 0.5%, respectively.
The researchers report that CAC successfully predicts CHD and CVD events for individuals with the metabolic syndrome, diabetes, or neither condition. In contrast, cIMT was not associated with CHD or CVD events within any disease condition.
Fully adjusted models revealed that, compared with a CAC score of 0, increasing CAC scores (1-99, 100-399, and ≥400) were associated with increases in CHD risk of 2.9-6.2-fold among those with diabetes, 3.9-11.9-fold among those with the metabolic syndrome, and 2.6-9.5-fold among those with neither condition. Similar results were observed for CVD risk.
Categories of cIMT, however, were not statistically significant predictors of CHD events for those with diabetes of the metabolic syndrome. Among individuals with neither condition, the risk for CHD was increased 2.8-fold for those in the fourth quartile of cIMT compared with the first quartile. No statistically significant relationship between CVD events and cIMT was observed in any of the three groups.
"Our data suggest CAC screening (with cIMT less useful) may improve CHD risk stratification in those with the metabolic syndrome and diabetes," remark the authors. "Those with the highest levels of CAC or cIMT are at highest risk, which may help motivate such individuals (and their physicians) to be more adherent to or to intensify treatment recommendations," they add.
The team concludes that while "guidelines do exist for treating subgroups of people with the metabolic syndrome or diabetes more aggressively than others (except in the presence of CHD)," a "more aggressive treatment approach" may be justified in those with very high levels of CAC.
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By Nikki Withers