Intraepidermal nerve fiber density and nerve conduction study parameters correlate with clinical staging of diabetic polyneuropathy

Aim and methodsTo assess the usefulness of the diagnostic and staging criteria for diabetic polyneuropathy (DP) by the Diabetic Neuropathy Study Group in Japan (DNSGJ) we examined clinical features, intraepidermal nerve fiber densities (IENFD) and nerve conduction studies (NCS) and coefficient of variation of the R-R intervals (CVR-R) in 44 patients with diabetes.ResultsThe patients were classified into stage I (n = 20), II (n = 6), III + IV (n = 12), and V (n = 6) according to the staging criteria by DNSGJ. IENFD decreased as stages progressed (13.8 ± 7.1 fiber/mm in stage I to 0.8 ± 1.3 fiber/mm in stage V). Compound motor and sensory action potential and motor and sensory nerve conduction velocity decreased with progressing stage. F-wave latency prolonged as stages progressed. CVR-R decreased with progressing stage (4.41% ± 2.65% in stage I to 1.33% ± 0.57% in stage V). IENFD correlated with the various parameters of NCS (r = 0.378–0.636, p < 0.05) and CVR-R (r = 0.399, p = 0.007).ConclusionsClinical staging for DP by DNSGJ reflects the results of small and large fiber neuropathy.