Glycemic control is related to the morphological severity of diabetic sensorimotor polyneuropathy

OBJECTIVE - The aim of the current study was to determine the independent c linical risk factors for predicting morphological severity of distal diabet ic sensorimotor polyneuropathy (DSP) as determined by fiber density (FD) on sural nerve biopsy. RESEARCH DESIGN AND METHODS - A total of 89 patients with both type 1 and t ype 2 diabetes, ascertained from a large therapeutic randomized clinical tr ial, were included in this observational cohort study. Morphological severi ty of DSP was expressed as the myelinated FD in the sural nerve biopsy. Gen eral linear models were used to assess the relationship between the morphol ogical severity of DSP and various clinical risk factors. RESULTS - Glycated hemoglobin (GHb) was significantly related to FD in univ ariate and multivariate regression analyses. This relationship was present in models in which GHb was handled either as a continuous variable or as a categorical variable with the highest significance level, with a GHb cutoff level of 9%. After dividing patients into groups with optimal to moderate (GHb less than or equal to9%) and suboptimal (GHb >9%) glycemic control, th e difference in FD between the two groups ranged between 3,461 and 2,334 pe r mm(2). FD was also significantly related to duration of diabetes and age of the patient. CONCLUSIONS - The severity of peripheral DSP express by morphological crite ria was significantly related to glycemic control in type 1 and type 2 diab etic patients. Inconsistent with previously published electrophysiological data demonstrating a correlation between height and conduction velocity, in creasing height is not associated with morphological severity. Based on the results of the present study, it might be hypothesized that improving glyc emic control will lessen severity of DSP in terms of FD loss in subjects wi th diabetes.