Benefits of Strict Glucose and Blood Pressure Control in Type 2 Diabetes

For decades, the treatment of type 2 diabetes has been based more on assumptions than on facts. Even the most crucial question—does a reduction in blood glucose help to prevent long-term complications—has remained unanswered. Now, 4 reports from the United Kingdom Prospective Diabetes Study (UKPDS)1 2 3 4 offer useful information on the benefits of treating hyperglycemia and hypertension in this disorder.Whereas the complications of type 1 diabetes are chiefly microvascular, patients with type 2 diabetes are prone to accelerated atherosclerosis.5 The most important macrovascular complication is coronary heart disease (CHD), which causes almost half the deaths in these patients. Although classic risk factors (ie, high total cholesterol, hypertension, and smoking) play a substantial part in pathogenesis, they do not explain the excess of macrovascular complications in type 2 diabetes. Therefore, the specific risk factors, particularly hyperglycemia, have been given increasing attention. In population-based prospective studies, hyperglycemia has indeed proved to be associated with risk of CHD in type 2 diabetes: a 1% change in glycohemoglobin (HbA1c) signifies about a 10% change in risk of CHD.6 7 Thus, there is potential, albeit modest, for reducing CHD events by lowering blood glucose.What is the evidence that improvement in glycemic control is beneficial in this respect? The first study aiming to address this question, the University Group Diabetes Program (UGDP), published in the 1970s,8 randomized ≈200 patients with type 2 diabetes to phenformin, tolbutamide, a fixed insulin dose, a variable insulin dose, or placebo. With phenformin and tolbutamide, cardiovascular mortality was higher than with insulin or placebo (for which …