Coronary artery calcification predicts coronary events in type 1 diabetes
medwireNews: The risk for coronary artery disease (CAD) increases significantly with increasing levels of coronary artery calcification (CAC) in individuals with type 1 diabetes, US researchers report.
Furthermore, Trevor Orchard (University of Pittsburgh, Pennsylvania) and co-investigators say their findings demonstrate that adding CAC measures to CAD risk models can “lead to improvement in prediction over established risk factors.”
The study included 292 individuals (mean age 39.4 years) with type 1 diabetes (mean duration 29.5 years) who had at least one CAC measurement and no evidence of CAD at baseline.
During an average 10.7 years of follow-up, 76 (26.0%) participants experienced a first incident CAD event, most commonly revascularization (32.9%), followed by nonfatal myocardial infarction (19.7%), physician-diagnosed angina (18.4%), fatal myocardial infarction (17.1%), and ECG-confirmed ischemia (11.8%).
The researchers report in Diabetologia that, compared with individuals with no CAC at baseline (Agatston score=0), those with an Agatston score of 1–99 had a significant 3.1-fold increased risk for CAD after adjustment for sex, diabetes duration, smoking, BMI, glycated hemoglobin (HbA1c), hypertension, urinary albumin excretion rate (AER), high-density lipoprotein (HDL)- and non-HDL-cholesterol, and statin use.
For individuals with baseline Agatston scores of 100–399 and 400 or higher, the risks were 4.4- and 4.8-fold higher, respectively, than for those with no CAC at baseline.
In a subgroup of 181 participants with repeated CAC measures, the team observed that individuals with annual CAC progression above the median rate of 0.24 were a significant 3.2 times more likely to develop CAD than those with progression below the median rate.
By contrast, CAC density was inversely associated with incident CAD, but only among participants with a CAC volume of at least 100. In this group, each standard deviation increase in CAC density was associated with a 70% reduction in the risk for CAD.
“Increasing CAC density is hypothesised to protect against CAD events because a calcified plaque is likely to be more stable than a soft plaque,” Orchard and co-authors remark.
The researchers also investigated whether CAC could improve risk prediction for CAD. They found that when they added CAC to a model that only included established risk factors, namely sex, diabetes duration, smoking, BMI, HbA1c, hypertension, urinary AER, cholesterol levels, and statin use, baseline CAC measures significantly improved the discriminatory power of the model by approximately 5 percentage points, from 80% to 85%.
Orchard et al note that the usefulness of CAC measures has already been demonstrated in type 2 diabetes and the current study “extends those findings to individuals with type 1 diabetes.”
They conclude: “Further research assessing the utility of CAC measurements in type 1 diabetes in better targeting interventions and improving CAD events and mortality outcomes is warranted.”
By Laura Cowen
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