FACTOR-64: Screening For Asymptomatic Obstructive CAD Among High-Risk Diabetic Patients Using CCTA
The use of coronary computed tomography angiography (CCTA) to screen for coronary artery disease (CAD) in asymptomatic patients with type 1 or type 2 diabetes “did not reduce the composite rate of all-cause mortality, nonfatal myocardial infarction (MI), or unstable angina requiring hospitalization at four years,” and is therefore not supported in this patient population, according to results from the FACTOR-64 trial presented Nov. 17 at AHA 2014 and simultaneously published in the Journal of the American Medical Association.
The study was led by Joseph B. Muhlestein, MD, FACC, Intermountain Medical Center Heart Institute, Murray, UT, and looked at 900 patients with type 1 or type 2 diabetes without symptoms of CAD within the Intermountain health care system. Patients were randomly assigned to CAD screening with CCTA (n = 452) or to standard national guidelines–based optimal diabetes care (n = 448) (targets: glycated hemoglobin level <7.0 percent, low-density lipoprotein cholesterol level <100mg/dL, systolic blood pressure <130mmHg), and were followed for at least three to five years.
Results showed at a mean follow-up time of four years, the primary outcome event rates – a composite of all-cause mortality, nonfatal MI, or unstable angina requiring hospitalization – were not significantly different between the CCTA and the control groups (6.2 percent [28 events] vs. 7.6 percent [34 events]; hazard ratio, 0.80 [95 percent CI, 0.49-1.32]; P = 0.38). Further, the incidence of the composite secondary end point of ischemic major adverse cardiovascular events also did not differ between groups (4.4 percent [20 events] vs. 3.8 percent [17 events]; hazard ratio, 1.15 [95 percent CI, 0.60-2.19]; P = 0.68).
“Coronary computed tomography angiography involves significant expense and radiation exposure, so that justification of routine screening requires demonstration of net benefit in an appropriately high-risk population,” the authors note. They ultimately conclude that their findings “do not support CCTA screening in this population.”
Raymond J. Gibbons, MD, FACC, Division of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, notes in a related editorial comment, “until future studies provide evidence of better patient outcomes with an imaging strategy, these results suggest that an ‘ounce of prevention’ with optimal guideline-directed medical therapy in asymptomatic patients with diabetes is more important than cardiac imaging. The challenge for clinicians is to more consistently deliver optimal medical therapy to all patients with diabetes. As practicing physicians realize, there are many obstacles in the current health care system to the achievement of this goal, but overcoming them is essential to prevent cardiac events in patients with diabetes.”
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