Glucose control in type 1 diabetes: from conventional to intensive therapy

The discovery of insulin at the University of Toronto in 1921 and its first administration on January 11, 1922, dramatically revolutionized the management and outcome of type 1 diabetes. Type 1 diabetes was transformed from a condition that was almost uniformly fatal into a chronic disease characterized by the long-term microvascular and macrovascular complications of diabetes. The Diabetes Control and Complications Trial (DCCT) (1), following the lead of smaller European studies, demonstrated conclusively that improved glycemic control, as assessed by glycated hemoglobin (Hb A1c), markedly reduced the development and progression of retinopathy, neuropathy, and nephropathy. These benefits were achieved by the implementation of intensive diabetes management regimens (2). Unfortunately, the advantages of intensive diabetes management were also accompanied by an increased rate of severe hypoglycemia and weight gain. Nonetheless, on balance, it is clear that the benefits of intensive therapy far outweigh the risks. Indeed, the concluding recommendation of the DCCT is that most patients with type 1 diabetes should be treated with intensive diabetes management with the goal of achieving the best possible glycemic control. This article will be divided into four sections providing clinically relevant information relating to the transferral of patients from conventional to intensive diabetes management. We will review the principles of intensive diabetes therapy: selection of patients; implementation of therapy; and assessment of outcome measures.