medwireNews: Coronary computed tomography angiography (CCTA) improves the ability of traditional risk factors to predict the long-term risk for major adverse cardiovascular events (MACEs) in asymptomatic individuals with type 2 diabetes, according to a prospective study.
The researchers comment: “Asymptomatic patients with [type 2 diabetes] and a greater coronary atherosclerotic burden on CCTA had a higher risk of MACEs, and patients with MACEs were more likely to have obstructive CAD [coronary artery disease].”
Multivariate analysis adjusted for age, male sex, hypertension, hyperlipidemia, smoking, estimated glomerular filtration rate, glycated hemoglobin, coronary artery calcium score (CACS), and CCTA findings found that obstructive CAD, defined as coronary artery obstruction of 50% or more, was associated with a significant 3.83-fold increased occurrence of MACEs during the 5-year follow-up period.
Furthermore, the researchers report that “coronary obstruction >70% was associated with the largest increase in the risk of developing composite MACE,” when compared with atheroma burden obstructive score, segment involvement score, and segment stenosis score.
The study enrolled 933 asymptomatic individuals with type 2 diabetes who had undergone CCTA and were followed up for long-term clinical outcomes. On CCTA, 374 participants (40%) were found to have obstructive CAD, while 45 (11%) had significant obstruction of 70% or more. A total of 94 MACEs were recorded during follow-up, of which 64% and 25% occurred in participants with CCTA findings of obstructive and significant obstructive CAD, respectively.
Kaplan–Meier curves indicated that “patients with obstructive CAD had a significantly higher cumulative incidence of MACE than the normal and nonobstructed groups,” say Kiyuk Chang (St Mary’s Hospital, The Catholic University of Korea) and colleagues. And among participants with obstructive CAD, the rates of MACE were significantly higher for those with three-vessel or left main disease, compared with those with one- or two-vessel disease, they note.
The researchers found that adding CCTA-detected obstructive CAD to the traditional risk factors of age, male sex, hypertension, hyperlipidemia, smoking, estimated glomerular filtration rate, and glycated hemoglobin levels significantly improved the performance of a risk prediction model based on C-statistics.
“The addition of obstructive CAD detected using CCTA provided a significant increase in prognostic value compared with conventional risk factors alone, whereas the addition of CACS did not,” they write in Diabetes Care.
The team concludes that while the high-risk features of the population studied, such as the presence of microalbuminuria, retinopathy, and a diabetes duration of more than 10 years, mean the findings are not generalizable to all asymptomatic patients with type 2 diabetes, they do from the basis for further investigation into the benefits of screening for CAD in specific subgroups of asymptomatic patients.
By Catherine Booth
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