Small fiber neuropathy more common for adults with latent autoimmune vs. type 2 diabetes
Patients with latent autoimmune diabetes of adulthood, or LADA, have lower nerve fiber density and may experience worse small fiber neuropathy than adults with type 2 diabetes, according to findings published in Diabetic Medicine.
“LADA is a progressive form of autoimmune diabetes, and because of its slow natural history, it is often misclassified as type 2 diabetes and, therefore, leads to a protracted period of poorer glycemic control, due to a delay in the introduction of insulin,” Uazman Alam, PhD, BSc, MBChB, MPHe, MRCP, senior clinical lecturer and honorary consultant physician in endocrinology and diabetes at the Institute of Ageing and Chronic Disease at the University of Liverpool, U.K., and colleagues wrote. “Given that poorer glycemic control is associated with an increased risk for the development of neuropathy in people with type 1 and type 2 diabetes, people with LADA may have a greater propensity for the development of neuropathy.”
Alam and colleagues conducted a cross-sectional study of consecutive age-matched adults with type 2 diabetes (n = 31; mean age, 58 years; 23% women), LADA (n = 31; mean age, 53.2 years; 52% women) and neither condition (n = 31; mean age, 53.5 years; 48% women) presenting at the Centre for Diabetes and Endocrine Research at Princess Alexandra Hospital and Mater Hospitals in Brisbane, Australia, and the Manchester Diabetes Centre of the Manchester Royal Infirmary in the U.K. Recruitment took place between 2009 and 2013. LADA was confirmed when a participant was not receiving insulin for a condition that began before age 50 years with anti-glutamic acid decarboxylase antibody positivity and no ketonuria diabetic ketoacidosis at diagnosis.
The researchers used the McGill visual analogue score, quantitative sensory testing, electrodiagnostic studies, corneal confocal microscopy, skin biopsy and immunohistochemistry to determine neuropathy presence and severity.
Participants with LADA had higher levels of HbA1c compared with those with type 2 diabetes and those without either condition (P < .0001). Meanwhile, participants with type 2 diabetes had elevated BMI compared with participants with LADA (P = .01) and those without either condition (P = .02).
The researchers found that neuropathy disability scores and McGill visual analogue scores did not differ significantly between those with LADA and those with type 2 diabetes, but there were more instances of overt neuropathy in those with LADA (n = 13) compared with those with type 2 diabetes (n = 5). Participants with LADA also had lower peroneal motor nerve conduction velocity (P = .04) and sural sensory nerve conduction velocity (P = .0005) compared with participants with type 2 diabetes.
No differences were found between the two groups in peroneal motor nerve amplitude, sural sensory nerve amplitude, vibration perception threshold, cold sensation threshold or warm sensation threshold. However, participants with LADA had lower intraepidermal nerve fiber density (P = .008), corneal nerve fiber density (P = .006) and corneal nerve branch density (P = .003) compared with participants with type 2 diabetes.
“People with LADA require assessment for small fiber neuropathy, as it may enable clinicians to risk-stratify these people and commence insulin earlier to limit the progression of neuropathy,” the researchers wrote. – by Phil Neuffer
Disclosures: The authors report no relevant financial disclosures.