[Hyperglycemia and cardiovascular risk: lessons from randomized trials]

Diabetes is a major cardiovascular risk factor However, hyperglycemia is much more closely associated with microangiopathy than with macrovascular complications. Epidemiologic studies have shown a 15% increase of myocardial infarction for 1% increase in HbA1c level. It is accepted but not absolutely demonstrated, that reduction of HbA1c results in an equal reduction of cardiovascular events. An initial good glycemic control has long-term benefical effects on the risk of cardiovascular disease. On the contrary, benefit of an intensive glucose control is not demonstrated in diabetic patients with previous myocardial infarction. Two recent studies (ACCORD and VADT) showed an increase of cardiovascular mortality by severe hypoglycemia. In diabetic patients with previous myocardial infarction, glycemic goal must be modulated by the hypoglycaemic risk. A goal of 7.5% HbA1c seems reasonable for the diabetic patients treated by sulfonylureas or insulin, at risk of hypoglycaemia. HbA1c target < 7% remains the general goal and HbA1c target < 6.5% is appropriated to the patients treated by insulin sensitizing medications without risk of hypoglycaemia.