Author Affiliations: Division of Metabolism, Endocrinology, and Nutrition, School of Medicine, and Diabetes Care Center, University of Washington, Seattle (Dr Hirsch); and Diabetes Research Center and Departments of Medicine and Pathology, Albert Einstein College of Medicine, Bronx, New York (Dr Brownlee).
In 1993, The Diabetes Control and Complications Trial1 demonstrated that intensive therapy lowered time-averaged blood glucose values (measured as hemoglobin A1C [HbA1C]) and significantly reduced development of microvascular complications in type 1 diabetes. For example, intensive therapy reduced the risk of sustained retinopathy progression by 73% compared with standard treatment. Such significant reductions led to the recommendation by professional societies that for microvascular disease prevention, the HbA1C goal for nonpregnant adults should be less than 7% or even less than 6.5% of total hemoglobin.
Irl B. Hirsch, Michael Brownlee. Beyond Hemoglobin A1c—Need for Additional Markers of Risk for Diabetic Microvascular Complications. JAMA. 2010;303(22):2291–2292. doi:10.1001/jama.2010.785