Type 2 diabetes is a growing, worldwide epidemic with significant clinical, social, and financial costs associated with the devastating microvascular and macrovascular complications of poorly controlled diabetes. Large randomized, controlled clinical trials, such as the Diabetes Control and Complication Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS), have demonstrated that tight glycemic control reduces the risk of microvascular diabetic complications in both type 1 diabetes and type 2 diabetes. Furthermore, long-term follow-up of the DCCT and UKPDS cohorts has shown the so-called legacy effect (i.e., a long-lasting positive effect of tight glucose control on diabetes complication), even if glucose control tends to deteriorate.