Ten Kate Q, Aanstoot HJ, Birnie E, Veeze H, Mul D.

GADA persistence and diabetes classification. Lancet Diabetes Endocrinol. 2016;4:563–564.

Testing for the persistence of glutamic acid decarboxylase antibodies (GADA) is worthwhile irrespective of diabetes duration, as it can help rectify possible misdiagnoses, according to this paper’s authors.

 

In a letter to The Lancet Diabetes & Endocrinology, the authors respond to a previous comment in the journal calling for an optimization of diagnostic accuracy at the onset of diabetes in children and adolescents. The Diabeter centres frequently see referred people with diabetes who have been potentially misclassified as having type 1 diabetes on the basis of clinical characteristics alone. The letter provides details of a cross-sectional study at Diabeter involving 990 people with diabetes.

 

Key findings:

• The overall prevalence of persistence of GADA positivity (levels of 6 U/mL or higher) was 58.8%. The mean disease duration was 8.5 years.
• The researchers said that, assuming that a raised GADA level implies an ongoing autoimmune attack against beta cells, these cases can therefore be classified as autoimmune.
• The presence of GADA positivity has a high predictive value for type 1 diabetes. Its prevalence is low, meanwhile, in monogenic diabetes and T2DM.
• Based on these findings, they estimated that “with a single GADA measurement in every 100 people with diabetes without an initial autoantibody assessment, we can properly classify a further 59 of them.” Further diagnostic steps would typically be needed in the other 41 cases.

 

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