Intensive Treatment of Type-1 Diabetes The Balance of Benefits and Risks in the DCCT/EDIC Study

With the discovery of insulin in 1921 and its rapid introduction into therapy in 1922, the complexion of type-1 diabetes changed completely. From a disease that inevitably led to death in diabetic coma within a few short years, type-1 diabetes morphed into a chronic disease as, in the 1930s, diabetic retinopathy, nephropathy, and neuropathy emerged as major complications. These complications afflicted sufferers with loss of vision, renal failure, pain, amputations, and death from cardiovascular disease (CVD) after 30–40 years. There ensued a long-standing debate as to whether these complications were caused by hyperglycemia and other consequences of insufficiently normalized metabolism or were simply an intrinsic parallel manifestation of diabetes that could not be prevented by insulin therapy. This question of whether normalization of blood glucose with intensive treatment would reduce the risk of diabetic complications compared with then-conventional insulin treatment, which only minimized or eliminated symptoms resulting from glycosuria, prevented spontaneous diabetic ketoacidosis and avoided hypoglycemia, could only be definitively answered by a long-term, randomized clinical trial testing the glucose hypothesis. Thus, the Diabetes Control and Complications Trial (DCCT) emerged, followed by the Epidemiology of Diabetes Interventions and Complications (EDIC) observational follow-up study of the same cohort of research volunteer patients.