ESPE Abstracts (2016) 86 P-P1-216

Thyroid and Islet Autoantibodies Predict Autoimmune Thyroid Disease Already at Diagnosis of Type 1 Diabetes

Berglind Jonsdottira, Christer Larssona, Annelie Carlssona, Gun Forsanderd, Sten Anders Ivarssona, Æke Lernmarka, Johnny Ludvigssonc, Claude Marcusb, Ulf Samuelssonc, Eva Örtqvistb & Helena Elding Larssona

aLund University, Lund, Sweden; bKaroliniska Insititute, Stockholm, Sweden; cLinköping University Hospital, Linköping, Sweden; dInsititute of Clinical Science, Gothenburg, Sweden

Background: Screening for autoimmune thyroid disease in children and adolescents with type 1 diabetes lacks consensus. Optimal screening methods should benefit the patients and reduce costs to healthcare.

Objective and hypotheses: To, at diagnosis of type 1 diabetes, determine the predictive value of thyroid autoantibodies, thyroid function, islet autoantibodies, and HLA-DQ for autoimmune thyroid disease.

Method: At diagnosis of type 1 diabetes, children (n=2433) were analysed for autoantibodies against thyroid peroxidase (TPOAb), thyroglobulin (TGAb), glutamic acid decarboxylase (GADA), insulin (IAA), insulinoma-associated protein-2 (IA-2A), and the three variants of the zinc transporter 8 (ZnT8A) as well as HLA-DQA1-B1 genotypes and thyroid function. After 5.1–9.5 years disease duration children treated with thyroxine were identified in the Swedish National Board of Health and Welfare Prescribed Drug Register.

Results: Thyroxine had been prescribed to 6% (147/2433; 66% girls). In patients below 5 years, female gender (HR=4.60 CI: 1.50–14.45, P=0.008) and GADA (HR=5.80, CI: 1.32–25.4, P=0.02) were significant predictors. In patients 5–10 years, TPOAb (HR=20.56, CI: 8.40–50.35, P<0.0001), TGAb (HR=3.40, CI: 1.42–8.13, P=0.006) and thyrotropin outside the reference limit (HR=3.64, CI: 1.72–7.69, P<0.001) were predictors while in the 10–15 year olds, TPOAb (HR=17.00, CI: 8.40–34.44, P<0.001) and thyrotropin outside the reference limit (HR=4.11, CI: 2.41–7.03, P<0.001) predicted future thyroxine prescription.

Conclusion: In this large nationwide study we found that TPOAb and thyrotropin in addition to GADA in the very young, analyzed at diagnosis of type 1 diabetes, were predictive of autoimmune thyroid disease. Since hypothyroidism in children and adolescents is important to recognize, we suggest that all children below 18 years of age would benefit to be tested for those parameters at clinical diagnosis of type 1 diabetes, and thereby optimize individualized screening during follow-up.