Endocrine Abstracts

Introduction: The American Diabetes Association recommends islet antibody testing for classification of diabetes in adults who have phenotypic risk factors that overlap with those for Type 1 diabetes (T1DM). We were keen to examine the prevalence of islet antibody testing in our T1DM population.

Methods: We reviewed the Beaumont Hospital electronic patient record Cellma for patients with Type 1 diabetes and identified those who had at least one islet autoantibody measured, including anti-glutamic acid decarboxylase (anti-GAD), anti-islet cell, anti-IA2A, anti-ZNT8, and anti-insulin antibodies.

Results: Of the 1,476 T1DM patients attending our diabetes service, only 407 (27.6%) had at least one islet antibody previously tested for. The most commonly measured antibody was GAD antibody; measured in 395 patients (26.8%), with 69.1% positivity. Islet cell antibody was measured in 273 (18.5%), with 29.3% positivity; anti-IA2A in 170 (11.5%), with 40.0% positivity; anti-ZNT8 in 157 (10.6%), with 47.8% positivity; and anti-insulin antibodies in 39 (2.6%), with 17.9% positivity. Among those tested, 44.5% had antibodies measured at diagnosis (12% of the total cohort) and 55.5% later in the disease course.

Conclusion: In this large tertiary hospital cohort, fewer than one-third of patients with T1DM had undergone islet autoantibody testing, with anti-GAD being the most frequently measured antibody. Testing occurred more often after diagnosis than at time of diagnosis.