Impaired glucose tolerance—does it cause neuropathy?

The publication of the Diabetes Control and Complications Trial (DCCT) laid to rest much of the controversy surrounding the role of hyperglycemia in diabetic neuropathy. This study showed that intensive insulin therapy, coupled with improved glycemic control, reduces the severity of diabetic complications and, more importantly, decreases the risk of developing these complications. This was the first large prospective study to show that careful regulation of blood glucose can prevent development of neuropathy in diabetic patients. Despite the evidence that hyperglycemia is coupled with neuropathy, it has been assumed that neuropathy results only from significant hyperglycemia and is not related to impaired glucose tolerance (IGT). In the presence of mild and episodic hyperglycemia, alternative causes for neuropathy are sought.