Patients with diabetes form a substantial proportion of patients with coronary artery disease.1 In some respects, the assessment, management, and outcome of these patients is different from patients without diabetes. This article outlines these differences in patients with symptomatic coronary disease and then focuses on the problems of managing high risk asymptomatic patients with diabetes. Should we and can we reliably identify these patients? Once identified, are they likely to benefit from intervention?

Diabetes is a strong and independent risk factor for the presence of coronary disease increasing the risk, particularly in women, between twofold and fourfold.2 In patients with diabetes, coronary disease is more extensive and severe, and cardiovascular death is three times more common than in non-diabetic patients.3 In patients with non-insulin dependent diabetes, a proportion of the increased risk can be explained by an excess and clustering of established cardiovascular risk factors. The mechanisms accounting for the remaining risk are poorly understood and relate in part to the consequences of hyperglycaemia and abnormalities of the coagulation and fibrinolytic systems.

In the settings of acute myocardial infarction and the secondary prevention of coronary disease, the relative benefits of medical treatment have been shown to be similar in patients with and without diabetes. In patients with diabetes and acute myocardial infarction, those with suboptimal blood glucose control have been shown to benefit substantially from insulin treatment.4

In patients with diabetes, most studies of coronary artery surgery have shown that the risks of death, myocardial infarction, and stroke are increased compared with non-diabetic patients.5In those with diabetes and multivessel disease, the long term outcome after coronary angioplasty6 and saphenous vein grafting alone are particularly disappointing compared with the very favourable outcome of diabetic patients after re-vascularisation using internal mammary artery grafting.7 Disappointing …