Involvement of the peripheral and autonomic nervous systems is probably the most common complication of diabetes. Clinical diabetic neuropathy is categorized into distinct syndromes according to the neurologic distribution, although many overlap syndromes occur. In both type 1 and type 2 diabetes, the prevalence varies with both the severity and duration of hyperglycemia.
This topic will review the epidemiology and classification of diabetic neuropathy. Other aspects of diabetic neuropathy are discussed separately. (See "Pathogenesis and prevention of diabetic polyneuropathy" and "Clinical manifestations and diagnosis of diabetic polyneuropathy" and "Diabetic autonomic neuropathy" and "Treatment of diabetic neuropathy" and "Diabetic amyotrophy and idiopathic lumbosacral radiculoplexus neuropathy".)
Diabetic polyneuropathy is the most common neuropathy in the Western world . Clinical and subclinical neuropathy has been estimated to occur in 10 to 100 percent of diabetic patients, depending upon the diagnostic criteria and patient populations examined. Prevalence is a function of disease duration, and a reasonable figure, based upon several large studies, is that approximately 50 percent of patients with diabetes will eventually develop neuropathy [1-3].
The prevalence and incidence of diabetic polyneuropathy can be illustrated by the following observations:
●In a landmark study, over 4400 patient with diabetes were serially evaluated over 25 years [4-6]. Neuropathy was defined as decreased sensation in the feet and depressed or absent ankle reflexes. The onset of neuropathy correlated positively with the duration of diabetes and, by 25 years, 50 percent of patients had neuropathy.