Follow-up of advanced diabetic neuropathy: useful variables and possible pitfalls.
BACKGROUND
The course of advanced diabetic neuropathy (DN) is largely unknown.


OBJECTIVE
To find variables allowing the follow-up of late stages of DN.


METHODS
Thirty diabetic patients with DN were observed. Patients were examined at intervals of 6 months over a period of 2 years. The compound muscle action potentials (CMAPs) were recorded in extensor digitorum brevis (EDB) and flexor hallucis brevis (FHB) muscles. Clinical severity of DN, nerve conduction studies (NCS), quantitative sensory testing (QST) and heart rate variability (HRV) were evaluated. The data were compared with age- and sex-matched controls.


RESULTS
All measures were sensitive to the detection of DN. Significant deterioration during follow-up was exclusively found in CMAP analysis of the EDB (p<0.05) and FHB muscles (p<0.03). NCS, QST and HRV remained unchanged within the 2 years of observation. Coincidental changes might occur, if only two time points are chosen for followup.


CONCLUSIONS
Our results indicate that ongoing axonopathy predominates in advanced DN. Repeated testing helps to minimize the impact of coincidental or chance changes in DN follow-up studies.
Krämer
H H
HH
Department of Neurology, Johannes Gutenberg-University, Langenbeckstr. 1, 55101 Mainz, Germany. kraemer@neurologie.klinik.uni-mainz.de
Rolke
R
R
Hecht
M
M
Bickel
A
A
Birklein
F
F
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000704:Analysis of Variance; D016022:Case-Control Studies; D003928:Diabetic Nephropathies / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology / Q000528:radiation effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009431:Neural Conduction / Q000502:physiology* / Q000528:radiation effects; D012684:Sensory Thresholds / Q000502:physiology / Q000528:radiation effects; D012720:Severity of Illness Index; D013997:Time Factors
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