title: Early electrophysiological abnormalities and clinical neuropathy: a prospective study in patients with type 1 diabetes.
abstract: OBJECTIVE
  The aim of this study was to elucidate whether subclinical nerve dysfunction as reflected by neurophysiological testing predicts the development of clinical neuropathy in patients with type 1 diabetes.
  
  
  METHODS
  Fifty-nine patients were studied twice with neurophysiological measurements at baseline and at follow-up. At baseline, patients were 15.5±3.22 years (range 7-22 years) of age, and duration of diabetes was 6.8±3.3 years. At follow-up, patients were 20-35 years of age, and disease duration was 20±5.3 years (range 10-31 years).
  
  
  RESULTS
  At baseline, patients showed modestly reduced nerve conduction velocities and amplitudes compared with healthy subjects, but all were free of clinical neuropathy. At follow-up, clinical neuropathy was present in nine (15%) patients. These patients had a more pronounced reduction in peroneal motor nerve conduction velocity (MCV), median MCV, and sural sensory nerve action potential at baseline (P<0.010-0.003). In simple logistic regression analyses, the predictor with the strongest association with clinical neuropathy was baseline HbA1c (R2=48%, odds ratio 7.9, P<0.002) followed by peroneal MCV at baseline (R2=38%, odds ratio 0.6, P<0.006). With the use of a stepwise forward analysis that included all predictors, first baseline HbA1c and then only peroneal MCV at baseline entered significantly (R2=61%). Neuropathy impairment assessment showed a stronger correlation with baseline HbA1c (ρ=0.40, P<0.002) than with follow-up HbA1c (ρ=0.034, P<0.007).
  
  
  CONCLUSIONS
  Early defects in nerve conduction velocity predict the development of diabetic neuropathy. However, the strongest predictor was HbA1c during the first years of the disease.
authors.affiliation: Corresponding author: Lars Hyllienmark, lars.hyllienmark@karolinska.se.
authors.forename: Lars
authors.initials: L
authors.lastname: Hyllienmark
authors.forename: Nils
authors.initials: N
authors.lastname: Alstrand
authors.forename: Björn
authors.initials: B
authors.lastname: Jonsson
authors.forename: Johnny
authors.initials: J
authors.lastname: Ludvigsson
authors.forename: Gerald
authors.initials: G
authors.lastname: Cooray
authors.forename: Jeanette
authors.initials: J
authors.lastname: Wahlberg-Topp
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism* / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D009431:Neural Conduction / Q000502:physiology; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D006442:Glycated Hemoglobin