Management of type 2 diabetes mellitus and cardiovascular risk: lessons from intervention trials.

Although the diagnosis of type 2 (noninsulin-dependent) diabetes mellitus is made when blood glucose levels exceed values which increase the risk of microvascular complications, macrovascular disease is the major complication of type 2 diabetes mellitus. Both epidemiological and prospective data have demonstrated that treatment of hyperglycaemia is markedly effective in reducing the risk of microvascular disease but is less potent in reducing that of myocardial infarction, stroke and peripheral vascular disease. Treatment of other cardiovascular risk factors, although by definition less prevalent than hyperglycaemia, appears to be more effective in preventing macrovascular disease than treatment of hyperglycaemia. In recent years, data from intervention trials have suggested that greater benefits with respect to the prevention of macrovascular disease can be achieved by effective treatment of hypertension and hypercholesterolaemia, and by the use of small doses of aspirin (acetylsalicylic acid) than by treating hyperglycaemia alone. On the other hand, the UK Prospective Diabetes Study (UKPDS), which examined the impact of intensive glucose and blood pressure (BP) control on micro- and macrovascular complications, is the only intervention trial to include only patients with type 2 diabetes mellitus. The UKPDS data, the epidemic increase in the number of patients with type 2 diabetes mellitus and their high cardiovascular risk have, however, initiated several new trials addressing, in particular, the possible benefits of treatment of the most common form of dyslipidaemia (high serum triglyceride and low high density lipoprotein cholesterol levels) in these patients. Type 2 diabetes mellitus is thus a disease associated with a high vascular risk, where the majority of patients need, and are likely to benefit from, pharmacological treatment of several cardiovascular risk factors provided treatment targets have not been achieved by life-style modification.