THE RESULTS of the Diabetes Control and Complications Trial have conclusively shown that improved glycemic control decreases the incidence of retinopathy, renal disease, and neuropathy in subjects with insulin-dependent diabetes mellitus (IDDM).1 However, a number of issues remain unresolved. Other data have suggested the existence of a glycemic threshold for diabetic proteinuria and retinopathy.2,3 If true, this might suggest a level beyond which improved glycemic control is unnecessary, thereby potentially reducing the risk for hypoglycemia in some subjects with IDDM. However, further analyses from the Diabetes Control and Complications Trial4 and the EURODIAB IDDM Complications Study5 did not find evidence for a glycemic threshold.
The duration of diabetes is also important in assessing the risk for complications. After a long duration of diabetes, diabetic complications may develop to some degree in almost all subjects.6 In this issue of the Archives, Orchard et al7 made