Patients with diabetes mellitus are at increased risk for myocardial infarction (MI) and diabetes is considered a coronary risk equivalent by the National Cholesterol Education Program , since type 2 diabetic patients without a prior MI have the same risk of developing an MI as nondiabetic patients who have already had an MI (figure 1) . (See "Prevalence of and risk factors for coronary heart disease in diabetes mellitus".)
Maintenance of strict glycemic control improves long-term microvascular outcomes in patients with both type 1 and type 2 diabetes. Intensive glycemic control aiming for near-normal levels has been shown to have a substantial beneficial effect (58 percent reduction in major CVD events) on macrovascular outcomes in type 1 diabetes, when applied early in the disease course and after one to two decades of therapy. In the setting of type 2 diabetes, with several co-prevalent risk factors for CVD, any beneficial effects of intensive glycemic control on macrovascular disease are likely to be less than those from similarly stringent control of blood pressure and lipid levels. In the acute setting, the evidence of benefit from strict glycemic control with insulin therapy in patients with acute MI is limited. The evidence in other groups of patient in inconsistent. (See "Glycemic control and intensive insulin therapy in critical illness" and "Glycemic control and vascular complications in type 1 diabetes mellitus" and "Glycemic control and vascular complications in type 2 diabetes mellitus".)
Poor glycemic control in diabetic patients and stress hyperglycemia in nondiabetic patients is associated with worse outcomes after acute MI but it is not fully understood as to whether strict glycemic control during AMI hospitalizations improves outcomes. These issues will be reviewed here.
The possible value of glycemic control in diabetic patients undergoing coronary artery bypass graft surgery is discussed separately. (See "Coronary artery revascularization in patients with diabetes mellitus and multivessel coronary artery disease", section on 'Perioperative glycemic control'.)
SERUM VERSUS BLOOD GLUCOSE
Practitioners should be aware that glucose measured in whole blood is generally 12 percent lower than values obtained from serum (or plasma). In the studies cited below, an attempt has been made to specify which was reported.