Patients with metabolic syndrome and diabetes are more likely to develop detectable levels of coronary artery calcium and to have greater progression of calcification compared with patients without those conditions, researchers found.

Compared with individuals with neither condition, those with either or both of the conditions had a significantly greater risk of developing calcification in between cardiac CT scans (RRs 1.6 to 2.0), according to Nathan Wong, PhD, MPH, of the University of California Irvine, and colleagues.

In addition, among those with detectable levels of calcium at baseline, progression was significantly greater in patients with either or both of the conditions (P<0.01 for all comparisons), the researchers reported in the April issue of JACC: Cardiovascular Imaging.

Progression of calcification significantly predicted coronary heart disease events in patients with metabolic syndrome alone (HR 4.1, 95% CI 2.0 to 8.5) and in those with diabetes alone (HR 4.9, 95% CI 1.3 to 18.4). Both of those patient groups have previously been shown to have a greater risk of cardiovascular events. “This begs the question of whether clinicians should be performing serial CT scans to identify patients with metabolic syndrome or diabetes and significant coronary artery calcium progression who may benefit from particularly aggressive medical therapy,” wrote Jason Kovacic, MD, PhD, and Valentin Fuster, MD, PhD, of Mount Sinai School of Medicine in New York City. “Although interesting in theory,” they added in an accompanying editorial, “in the current climate of cost containment and clinical use appropriateness criteria, we believe that this use of resources would be unlikely to gain widespread acceptance.” Wong and colleagues examined data from the Multiethnic Study of Atherosclerosis (MESA). The current analysis included 5,662 adults (mean age 61) who were free of cardiovascular disease at baseline and who received both a baseline and follow-up cardiac CT scan. The average time between the two scans was 2.4 years. Overall, 25.2% of the participants had metabolic syndrome only, 3.5% had diabetes only, 9% had both, and 62.3% had neither. The prevalence of detectable coronary artery calcium at baseline ranged from 44% for those with neither condition to 62% for those with both conditions. Compared with patients with neither metabolic syndrome nor diabetes, the relative risks of developing coronary artery calcium in between the two scans were higher for patients with the conditions:   Diabetes only (RR 1.6, 95% CI 1.0 to 2.6)   Metabolic syndrome only (RR 1.8, 95% CI 1.5 to 2.2)   Both conditions (RR 2.0, 95% CI 1.5 to 2.8) Similarly, the absolute increase in coronary artery calcium volume score was significantly greater for patients with metabolic syndrome only (7.4), diabetes only (16.7), and both conditions (22.4) compared with those with neither condition (0.0; P<0.01 for all). The progression of coronary calcium was most strongly related to increases in glucose and blood pressure. The researchers acknowledged some limitations of the analysis, including the assumption that the progression of coronary calcium was linear in between the two scans, the exclusion of patients who had a coronary heart disease event between the two scans, and the possibility that a different definition of metabolic syndrome could have influenced the results. Kovacic and Fuster noted that the study also was limited by the lack of information on renal function and statin use. "Nevertheless," they wrote, "we believe that these caveats would appear unlikely to have made an appreciable impact on the overall results or conclusions."