L'etude clinique du mois. Controle glycemique et morbimortalite cardio-vasculaire chez le patient diabetique de type 2. Resultats des etudes ACCORD, ADVANCE et VA-Diabetes.

Type 2 diabetes is associated with a high risk of complications, essentially macrovascular events. Surprisingly, the effect of improved glucose control on coronary and cerebrovascular complications in this population remains questionable. Furthermore, the target level of glycated haemoglobin (HbA1c) to minimise the risk of diabetic complications is controversial. We report the results of three recent randomised control trials (ACCORD, ADVANCE, Veterans Affairs Diabetes), which assessed the impact on cardiovascular events of intensive glucose-lowering therapy. None of these studies was able to demonstrate a significant reduction of cardiovascular events in the intensive group as compared to the standard group. On the contrary, in ACCORD, the study with the most ambitious goal (HbA1c < 6%), the overall and cardiovascular mortality was greater in the intensive group. In contrast, in the ADVANCE trial, the mortality and the incidence of cardiovascular events were not statistically different between the two treatment groups, whereas the risk of microangiopathic complications, especially nephropathy, was significantly decreased in the intensive group (HbA1c < or = 6.5%, with modified release gliclazide as main treatment). Finally, VA-Diabetes showed that the effect of better glucose control on cardiovascular complications disappeared with duration of the disease and that the risk of cardiovascular events increased in patients with severe hypoglycaemic episodes. In the three studies, the hypoglycaemic risk was indeed increased in the intensive group, which may contribute to reduce the positive impact of better glucose control on cardiovascular complications. The best way to protect type 2 diabetic patients against coronary and cerebrovascular disease is to target all cardiovascular risk factors.