No Added Benefit from Screening for Coronary Artery Disease in Diabetes

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No Added Benefit from Screening for Coronary Artery Disease in Diabetes
No Added Benefit from Screening for Coronary Artery Disease in Diabetes

Screening high-risk patients with diabetes for asymptomatic obstructive coronary artery disease (CAD) using coronary CT angiography (CCTA) did not confer significant clinical benefit, according to a new study presented at the American Heart Association's Scientific Sessions 2014.

In the FACTOR-64 trial, Joseph B. Muhlestein, MD, who is with Intermountain Medical Center in Murray, Utah and his colleagues conducted a study of 900 high-risk patients with diabetes. The patients were randomly assigned to a control arm (n=448), in which they received standard medical therapy, or to an intervention arm, in which patients received treatment based on results of 64-slice CCTA (n=452).

The researchers had theorized that CCTA could provide early CAD information on both myocardial ischemia and plaque burden. It was hoped that such information could guide preventative therapy and reduce future cardiovascular (CV) events in high-risk asymptomatic patients with diabetes

In the current study, patients randomly assigned to CCTA were managed by their physicians according to pre-specified trial recommendations based on the results of CCTA screening. All of these patients were recruited from 45 clinics and were enrolled at a single site coordinating center. 

The mean age of the patients was 61 years and 52% were men. All patients had type 1 or type 2 diabetes for at least 3 to 5 years duration, with a mean duration of 13 years, and were asymptomatic of CAD.

The primary endpoint was a composite of all-cause mortality, nonfatal myocardial infarction (MI) and hospitalization for unstable angina.

Overall, the presence of CAD or coronary artery calcium found on CCTA resulted in additional diagnostics, more aggressive risk factor management, or both, in more than two-thirds of patients, leading to coronary revascularization in 5.8% of the CCTA group. Statin use also appeared to be greater in the CCTA group at 1 year, according to data that was simultaneously published in JAMA.

Despite the differences in management based on CCTA, however, the researchers found no significant clinical difference in the primary endpoint between the CCTA and control groups (6.2% vs. 7.6%; P=.38) at 4 years. Further, incidence of the composite secondary endpoint of ischemic major adverse CV events, including CAD death, nonfatal MI or unstable angina, did not differ significantly between groups (4.4% vs. 3.8%; P=.68).

In light of the results, the researchers concluded that CCTA screening resulted in a modest number of protocol-recommended coronary revascularization procedures and a significant increase in the use of statin therapy. However, CCTA screening did not demonstrate a significant reduction in the primary clinical endpoint at 4 years of follow-up.

Endocrinologist Robert Eckel, MD, who is an AHA spokesman, said the results are not surprising. He said the findings are important because they provide reassuring data that the current guidelines are adequate. 

“The general idea is finding more disease or less disease as a predictor. It is not a routine test now nor does it appear that it should be,” said Dr. Eckel in an interview with Endocrinology Advisor.

Reference

  1. Muhlestein JB et al. LBCT.02 – Anti-Lipid Therapy and Prevention of CAD. Screening For Asymptomatic Obstructive Coronary Artery Disease Among High-Risk Diabetic Patients Using Coronary CT Angiography: Primary Results of FACTOR-64, a Randomized Controlled Trial. Presented at: American Heart Association's Scientific Sessions 2014; Nov. 15-19, 2014; Chicago.
  2. Muhlestein JB et al. JAMA. 2014;doi:10.1001/jama.201415825.
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