Patients with type 2 diabetes mellitus often develop micro- and macrovascular complications. In 25% of them, complications are already present at the time of diagnosis. The principal objective of the United Kingdom prospective diabetes study was to determine if good blood glucose control and adequate treatment of hypertension in patients with type 2 diabetes mellitus can prevent development of diabetes-related complications. The question was also studied if they way in which this blood glucose control was achieved and the way of treating the blood pressure affected the prognosis. Blood glucose control was found to reduce the incidence of--especially--microvascular complications. Oral hypoglycaemic agents and insulin both play an important p...