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Screening for Cardiac Disease in Asymptomatic Patients with Type 2 Diabetes

Overall cardiac risk was relatively low, and screening was of no benefit.

Some professional organizations recommend screening for coronary artery disease in asymptomatic patients with type 2 diabetes, despite a lack of evidence to support this practice. To determine whether screening for CAD benefits diabetic patients, researchers enrolled 1123 adults with type 2 diabetes (mean age, 60; mean duration of diabetes, 8 years; no history of cardiac symptoms) in the U.S. and Canada. Participants were randomized to receive adenosine-stress myocardial perfusion imaging or no testing. All patients received usual care for diabetes, and screened subjects (and their physicians) were apprised of stress test results. Use of preventive medications, such as aspirin and antihypertensives, rose substantially in both groups during the study.

Forty-four unscreened patients and 31 screened patients underwent revascularization during the study. During a mean follow-up of 5 years, screened patients suffered 15 fatal or nonfatal cardiac events, versus 17 in the control group (about 0.6% annually for each group). The adverse event rate was five- to sixfold higher in subjects with large perfusion defects than in those with no or small defects, but the positive predictive value of moderate or large perfusion defects was still only 12%. The negative predictive value of a negative test was 98%, but half of all events still occurred in participants with negative test results.

Comment: The rate of CAD events was roughly one quarter of what was expected, probably because of exclusion criteria and aggressive medical management of risk factors in both groups. However, these results should reassure clinicians that they can focus on controlling risk factors in patients with type 2 diabetes and employ testing only in the limited subset of patients who have symptoms.

— Thomas L. Schwenk, MD

Published in Journal Watch General Medicine April 21, 2009

Citation(s):

Young LH et al. Cardiac outcomes after screening for asymptomatic coronary artery disease in patients with type 2 diabetes: The DIAD study. A randomized controlled trial. JAMA 2009 Apr 15; 301:1547.

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