In vivo corneal confocal microscopy and prediction of future-incident neuropathy in type 1 diabetes: a preliminary longitudinal analysis.
OBJECTIVE
In vivo corneal confocal microscopy (IVCCM) has been established in cross-sectional studies as a valid measure for the identification of diabetic sensorimotor polyneuropathy (DSP). We aimed to determine the predictive validity of a baseline IVCCM measure in identifying future DSP onset in patients with type 1 diabetes.


METHODS
We followed 65 patients with type 1 diabetes without DSP at baseline. They were followed longitudinally for a mean of 3.5±0.9 years and underwent IVCCM, clinical and electrophysiologic examinations at baseline and follow up. At the end of follow up, participants were assigned as new-onset cases of DSP or as controls. Predictive validity was assessed using receiver operating characteristic curves.


RESULTS
At baseline, participants were 34±15 years of age with mean diabetes duration of 18±12 years. The 11 (17%) new-onset cases of DSP were similar to the 54 (83%) controls in baseline age, diabetes duration, gender, glycated hemoglobin levels and electrophysiologic parameters (p≥0.20). However, cases of new onset had significantly lower baseline corneal nerve fibre length (CNFL) and branch density (p<0.05). For identification of new-onset cases, area under the receiver operating characteristic curve for CNFL was 0.78 with an optimal threshold of 14.9 mm/mm(2) (sensitivity=0.82, specificity=0.69).


CONCLUSIONS
Despite similar clinical and electrophysiologic parameters, participants with type 1 diabetes at risk for future DSP had significantly lower baseline IVCCM measures. CNFL may have applicability in identifying high-risk patients for therapeutic intervention in clinical research and practice.
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Leif E
LE
Lovblom
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Elise M
EM
Halpern
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Tong
T
Wu
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Dylan
D
Kelly
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Ausma
A
Ahmed
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Genevieve
G
Boulet
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Andrej
A
Orszag
Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Eduardo
E
Ng
Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Mylan
M
Ngo
Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Vera
V
Bril
Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada. Electronic address: bperkins@mtsinai.on.ca.
Bruce A
BA
Perkins
D000328:Adult; D002170:Canada; D003315:Cornea / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000473:pathology*; D003929:Diabetic Neuropathies / Q000150:complications / Q000473:pathology*; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve
corneal confocal microscopy; diabetic neuropathy; diabète de type 1; microscopie confocale cornéenne; neuropathie diabétique; type 1 diabetes