Oral Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2017

Corneal confocal microscopy assessed nerve structure in Type 1 diabetes adults correlates with non-invasive measures of tissue health (skin autofluorescence and retinal vessel calibres) (#33)

Andrzej Januszewski 1 2 , Acyel Al-Alosi 2 , Rachel McGrath 3 , Emma Scott 2 3 , Gregory Fulcher 3 , Alicia Jenkins 1 2
  1. Department of Medicine, University of Melbourne, Fitzroy, VIC, Australia
  2. NHMRC Clinical Trials Centre, University of Sydney, Camperdown, NSW, Australia
  3. Department of Endocrinology, Royal North Shore Hospital, University of Sydney, St Leonards, NSW, Australia

Introduction: Tools for early detection of neuropathy and other tissue damage in diabetes are of interest. Corneal confocal microscopy (CCM), which assesses corneal structures, is increasingly available. CCM measures have been associated with neuropathy in diabetes, but have not been related to other measures of tissue health, including retinal vessel calibre and skin autofluorescence (SAF, which correlates with AGEs); which are associated with and predictive of chronic complications.

Aims: To determine if CCM measures (1) differ between non-diabetic (CON) and T1D, and by T1D complication (CX) status; and (2) correlate with (a) retinal vascular parameters and (b) SAF.

Methods:  Cross-sectional study: T1D subjects (n=33, including 13 CX+); mean±SD age 44±17 yrs; T1D duration 22±14 yrs and n=10 healthy controls (CON). Quantification: CCM HRT-3 (Heidelberg Engineering, Germany): corneal nerve fibre density (NFD), nerve branch density (NBD), nerve fibre length (NFL), endothelial cell density (ECD); Forearm SAF: AGE Reader (Diagnoptics, Netherlands). Retinal posterior pole images (CR-2 camera, Canon, Japan) graded for Central Retinal Arteriolar and Venular Equivalents (CRAE and CRVE) and arterio-venous ratio (AVR)( Vampire software, University of Dundee, Scotland).

Results: CCM differences between groups and correlations: NFD and NFL differences for CON vs. T1D and T1DCX- vs. T1DCX+ remained significant after adjustment for age and T1D duration respectively. SAF:  T1D SAF correlated inversely with NFD (r=-0.48; p=0.006), NBD (r=-0.48; p=0.006) and NFL (r=-0.54; p=0.002). Retinal vessels: CRAE and CRVE (but not AVR) correlated with NFD (r=0.49; p=0.005, r=0.41; p=0.02), NBD (r=0.41; p=0.02, r=0.43; p=0.01) and NFL (r=0.47; p=0.007, r=0.41; p=0.02). In T1D CX- AVR and in CX+ CRAE correlated with NFL (r=-0.54, r=0.02, r=0.56; p=0.04 respectively).

Conclusions: Corneal nerve measures and SAF are worse in T1D and in T1D CX+ vs. CX-. Some CCM measures inversely correlate with SAF and retinal vessel calibres. Such tools may facilitate diabetes monitoring.

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