Hyperglycemia and cardiovascular disease in type 2 diabetes

Cardiovascular disease (coronary heart disease, stroke, peripheral vascular disease) is the most important cause of mortality and morbidity among patients with type 2 diabetes. Conventional risk factors contribute similarly to macrovascular complications in patients with type 2 diabetes and nondiabetic subjects, and therefore, other explanations have been sought for enhanced atherothrombosis in type 2 diabetes. Among characteristics specific for type 2 diabetes, hyperglycemia has recently been a focus of keen research. A recent meta-analysis of 20 studies on nondiabetic subjects has demonstrated that in the nondiabetic range of glycemia (<6.1 mmol/l), increased glucose is already associated with an increased risk for cardiovascular disease. Similarly, 12 recent prospective studies have convincingly indicated that hyperglycemia contributes to cardiovascular complications in patients with type 2 diabetes. The recently published U.K. Prospective Diabetes Study has shown that intensive glucose control reduces effectively microvascular complications among patients with type 2 diabetes, but that its effect on the prevention of cardiovascular complications was limited. Given the fact that in the U.K. Prospective Diabetes Study, none of the treatment modalities was particularly effective in reducing glucose, this underestimates the true potential of the correction of hyperglycemia in the prevention of cardiovascular disease in type 2 diabetes. However, in addition to intensive therapy of hyperglycemia, other conventional risk factors should also be normalized to prevent cardiovascular disease in patients with type 2 diabetes.