Diabetes

Diabetes is an increasingly common disorder in the US. It affects an estimated 20.6 million American adults aged 20 years and older, 9.7 million of whom are women.³⁷ The prevalence of diabetes in the US has risen by more than 60% since 1990,¹ and is expected to continue growing. In 2004, the US Department of Health and Human Services reported that 40% of US adults aged 40 to 74 years have pre-diabetes, which increases their odds of developing diabetes.¹

Click on the links below for more information:

• Diabetes and Cardiovascular Risk
• Diabetes and Silent Ischemia
• CAD Detection in Diabetics

Diabetes and Cardiovascular Risk

• Diabetics without overt evidence of CHD have a risk of MI similar to nondiabetics who have already had an MI.³⁸
• Diabetes is associated with a high prevalence of cardiac risk factors in US adults.³⁹
  • Patients with diabetes and no CHD had significantly higher mean risk factor counts than those with CHD and no diabetes or no CHD and no diabetes (2.6 vs 2.4 and 1.4, respectively; both P < .01)
  • Patients with CHD and diabetes had the highest mean number of risk factors (3.4).
• Cardiac death rates are 2 to 4 times higher among diabetic adults compared with their nondiabetic counterparts.¹
• ≥65% of diabetic patients die from some form of heart or blood vessel disease.¹
• Diabetic women are at greater risk of heart disease than diabetic men.⁴⁰
• Coronary artery disease (CAD) is the leading cause of death among diabetic women.⁴¹

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Diabetes and Silent Ischemia

Diabetic patients appear to be at increased risk for silent ischemia. The pain response to ischemia is often blunted in diabetic patients,²³ and therefore ischemic disease may not trigger symptoms.

In the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study⁴²:

• 22% of patients randomized to undergo pharmacologic-stress myocardial perfusion imaging (MPI) had silent ischemia.
• 41% of patients with silent ischemia would not have been identified by screening based on American Diabetes Association guidelines.

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CAD Detection in Diabetics

Diabetic patients are at increased risk for heart disease, and those with CAD can often be asymptomatic or can present with atypical symptoms.²³ Therefore, diabetics may require more frequent cardiac testing.⁴¹

Diagnosis of CAD can be more difficult in the presence of diabetes:

• Exercise electrocardiography (ECG) can be a less reliable indicator of significant CAD in diabetics.⁹
• Exercise ECG in the cardiac assessment of diabetics can be affected by^9,23:
• Decreased exercise capacity
• Inability to reach target heart rates
• Absence of chest pain during exercise
• MPI with stress single-photon emission computed tomography (SPECT) has significant risk-stratification value in diabetic patients.^41,43
• Stress MPI has been shown to be especially useful in diabetics who have mildly impaired left ventricular function or asynergy but no chest pain.⁴⁴
• More diabetic than nondiabetic patients may require special considerations regarding the choice of an imaging procedure. In a large study of patients referred for SPECT MPI, significantly more diabetics required pharmacologic stress due to their inability to exercise adequately (Figure 6).⁴¹

Figure 6. Percentage of Diabetic and Nondiabetic Patients Requiring Pharmacologic Stress⁴¹

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