Polyneuropathy in Diabetes Mellitus, Type 1

abstract & commentary

Source: Christen WG, et al. Risk factors for progression of distal symmetric polyneuropathy in type 1 diabetes mellitus. Am J Epidemiol 1999;150:1142-1151.

Among patients older than 30 years and suffering insulin-required type 1 diabetes, as many as 60% will sooner or later develop distal, symmetric polyneuropathy. No direct therapy or anticipatory medications have as yet appeared either to decrease its incidence or slow its progression. Risk factors, however, have been identified and are carefully identified and discussed by Christen and colleagues.

The initial study from which complications were identified involved 497 type 1 diabetics collected from 22 clinical centers. Their ages ranged from 18-56 years on entry and insulin treatment had ranged between 1-15 years. The study target was to determine whether sorbital, an aldose reductase inhibitor, would reduce the usual 60% risk that type 1 diabetics would develop distal symmetric polyneuropathy by age 31 years. The results were recorded in two papers (Ann Intern Med 1995;122:561-568; Neurology 1993;43:1141-1149). Relative risks of neuropathy among participants were identified as 1) having increased percentage levels of glycosylated hemoglobin (GSH) during the trial and 2) giving a history of ever being cigarette smokers. The present reanalysis added additional risk factors to the original findings. These included: entry risk factors for DSP in type 1 diabetes included age older than 30 years at onset, had a disease experience of more than 15 years, an elevated blood pressure, elevated serum cholesterol, smoking at any time, height greater than average, and female gender. GSH levels lying between 10.2 and 13.5 tripled the incidence of DSPs, whereas those with GSH levels more than 13.5% ran a six-fold risk of having severe type 1 diabetic neuropathy.

Commentary

Type 1 diabetes results from an autoimmune disorder that attacks and destroys the beta-insulin-generating cells of the pancreas. This in itself leads to varying glucose concentrations in the body, making difficult protective efforts for stabilizing blood glucose levels. Neurology Alert urges physicians and neurologists to make every effort to keep total glycosylated hemoglobin below 10.2 so as to prevent severe retinopathy or neuropathy in patients with type 1 diabetes. This article additionally emphasizes the above newly established qualities as risk factors to preceding reports. —fp

To prevent severe retinopathy or neuropathy, physicians are advised to keep levels of total glycosylated hemoglobin in patients below:

a. 13.5.

b. 15.

c. 12.3.

d. 10.2.