CORRESPONDENCE: LETTER TO THE EDITOR
Is Appropriate Use Criteria for Cardiac Radionuclide Imaging in Asymptomatic Diabetic Patients Evidence Based?
Ankur Sethi, MD*,
Amol Bahekar, MD, MPH and
Rohit Bhuriya, MD
* Department of Medicine, Rosalind Franklin University/Chicago Medical School, 308 Washington Boulevard, Oak Park, Illinois 60302 (Email: drankursethi{at}gmail.com).
We write in reference to the recent article in the Journal, the 2009 Appropriate Use Criteria for Cardiac Radionuclide Imaging (RNI), which was published by the American College of Cardiology and endorsed by many other professional societies (1). This document was anticipated to impact physician decision making, test performance, and reimbursement policy.
We find the use of RNI for asymptomatic patients with diabetes mellitus (patients >40 years old) and other coronary risk equivalents that were considered appropriate in that document without sufficient evidence. Diabetic patients have a high incidence of coronary artery disease (CAD); therefore, an intensive primary and secondary prevention is recommended by various professional societies. But the strategy of routine RNI for all asymptomatic patients cannot be considered appropriate. The DIAD (Detection of Ischemia in Asymptomatic Diabetics) study was a prospective randomized trial evaluating outcomes after screening for asymptomatic CAD in type 2 diabetic patients (2). Although the study was underpowered to detect the pre-specified difference, due to a low rate of cardiac events, it ruled out any major benefit of routine screening. Even moderate or large defects had a positive predictive value of just 12% for cardiac events. Also, there was no apparent difference in the use of interventions for risk modifications between the 2 groups based upon results of screening. The recent BARI 2D (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes) trial, which randomly assigned patients with type 2 diabetes and stable CAD to immediate revascularization with intensive medical therapy versus only intensive medical therapy, failed to show to any difference in mortality or major cardiovascular events (3). The COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial also showed that percutaneous intervention with optimal medical therapy was no better than optimal medical therapy alone for patients with stable CAD in general and for a subgroup of patients with diabetes specifically (4).
Thus, so far, revascularization has not proven beneficial for patients with asymptomatic or stable patients with CAD in terms of mortality and major cardiac events. A possible benefit of relief from angina does not hold true for subjects who are asymptomatic at baseline. In all of these trials, large proportions of patients in both groups received aggressive evidence-based interventions for cardiovascular risk reduction as recommended by various professional societies, and that could explain the low event rates. So, if an aggressive risk reduction strategy for asymptomatic high-risk patients can lead to a substantial decrease in cardiac events without any additional benefit from revascularization, the role of additional cardiac RNI is unclear. Routine RNI can be of use, if we can identify a subgroup of asymptomatic patients with additional risk factors who can benefit from revascularization or screening. The American Diabetic Association acknowledges the dearth of evidence in support of screening asymptomatic diabetic patients for CAD, and deemed it controversial (5).
The Centers for Disease Control estimates that about 33.9% of the U.S. population older than 40 years of age have diabetes (6). As per the appropriate use criteria, these patients would represent a high-risk group for whom cardiac RNI would be considered appropriate. In most places, a cardiac RNI would cost about U.S. $700 to $1,400. That would put enormous pressure on health care resources without any clear benefit.
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1. Hendel RC, Berman DS, Di Carli MF, et al. ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 appropriate use criteria for cardiac radionuclide imaging: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the American Society of Nuclear Cardiology, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the Society of Cardiovascular Computed Tomography, the Society for Cardiovascular Magnetic Resonance, and the Society of Nuclear Medicine J Am Coll Cardiol 2009;53:2201-2229.[Free Full Text]2. Young LH, Wackers FJ, Chyun DA, et al. DIAD Investigators Cardiac outcomes after screening for asymptomatic coronary artery disease in patients with type 2 diabetes. The DIAD study: a randomized controlled trial. JAMA 2009;301:1547-1555.[Abstract/Free Full Text] 3. Frye RL, August P, Brooks MM, et al. BARI 2D Study Group A randomized trial of therapies for type 2 diabetes and coronary artery disease N Engl J Med 2009;360:2503-2515.[CrossRef][Medline] 4. Boden WE, O'Rourke RA, Teo KK, et al. COURAGE Trial Research Group Optimal medical therapy with or without PCI for stable coronary disease N Engl J Med 2007;356:1503-1516.[CrossRef][Medline] 5. Standards of medical care in diabetes—2009 Diabet Care 2009;32(Suppl):13-61.[CrossRef] 6. Centers for Disease Control National Diabetes Fact Sheet, 2007 http://www.cdc.gov/diabetes/pubs/pdf/ndfs_2007.pdf 2009Accessed July 12, 2009.
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ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 Appropriate Use Criteria for Cardiac Radionuclide Imaging: A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the American Society of Nuclear Cardiology, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the Society of Cardiovascular Computed Tomography, the Society for Cardiovascular Magnetic Resonance, and the Society of Nuclear Medicine Endorsed by the American College of Emergency Physicians
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