Diagnosis of Neuropathy and Risk Factors for Corneal Nerve Loss in Type 1 and Type 2 Diabetes: A Corneal Confocal Microscopy Study

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Shazli Azmi
  • Ioannis Petropoulos
  • Georgios Ponirakis
  • Uazman Alam
  • Omar Asghar
  • Andrew Marshall
  • Catherine Fullwood
  • Caroline Abbott
  • Giuseppe Lauria
  • Catharina G Faber
  • Handrean Soran
  • Nathan Efron
  • Rayaz Malik


OBJECTIVE To assess the diagnostic utility of corneal confocal microscopy (CCM) for diabetic peripheral neuropathy (DPN) and the risk factors for corneal nerve loss. RESEARCH DESIGN AND METHODS A total of 490 participants, including 72 healthy control subjects, 149 with type 1 diabetes, and 269 with type 2 diabetes, underwent detailed assessment of peripheral neuropathy and CCM in relation to risk factors. RESULTS Corneal nerve fiber density (CNFD) (P < 0.0001 and P < 0.0001), corneal nerve fiber branch density (CNBD) (P < 0.0001 and P < 0.0001), and corneal nerve fiber length (CNFL) (P < 0.0001 and P = 0.02) were significantly lower in patients with type 1 and type 2 diabetes compared with control subjects. CNFD (P < 0.0001), CNBD (P < 0.0001), and CNFL (P < 0.0001) were lower in type 1 diabetes compared with type 2 diabetes. Receiver operating characteristic curve analysis for the diagnosis of DPN demonstrated a good area under the curve for CNFD of 0.81, CNBD of 0.74, and CNFL of 0.73. Multivariable regression analysis showed a significant association among reduced CNFL with age (b =-0.27, P = 0.007), HbA 1c (b=-1.1; P = 0.01), and weight (b=-0.14; P = 0.03) in patients with type 2 diabetes and with duration of diabetes (b=-0.13; P = 0.02), LDL cholesterol (b=1.8, P = 0.04), and triglycerides (b =-2.87; P = 0.009) in patients with type 1 diabetes. CONCLUSIONS CCM identifies more severe corneal nerve loss in patients with type 1 diabetes compared with type 2 diabetes and shows good diagnostic accuracy for DPN. Furthermore, the risk factors for a reduction in corneal nerve fiber length differ between type 1 and type 2 diabetes.

Bibliographical metadata

Original languageEnglish
Pages (from-to)150-156
Number of pages7
JournalDiabetes Care
Issue number1
Early online date3 Nov 2020
Publication statusPublished - 1 Jan 2021

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