Levothyroxine in euthyroid autoimmune thyroiditis and type 1 diabetes: a randomised, controlled trial.

Author(s): Karges B, Muche R, Knerr I, Ertelt W, Wiesel T, Hub R, Neu A, Klinghammer A, Aufschild J, Rapp A, Schirbel A, Boehm BO, Debatin KM, Heinze E, Karges W

Affiliation(s): Division of Pediatric Endocrinology and Diabetes, University Children's Hospital Ulm, Germany, Institute of Biometrics, University of Ulm, Germany, University Children's Hospital Erlangen, Germany, Children's Hospital Heidenheim, Germany, Children's Hospital Datteln, Germany, University Children's Hospital Tubingen, Germany, Children's Hospital Chemnitz, Germany, Dept. of Nuclear Medicine, University of Wurzburg, Germany, Division of Endocrinology, Clinic for Internal Medicine I, University of Ulm, Germany, Division of Endocrinology and Diabetes, RWTH Aachen University, Germany.

Publication date & source: 2007-02-13, J Clin Endocrinol Metab., [Epub ahead of print]

Publication type:

Context: Patients with type 1 diabetes (T1D) have an increased risk of autoimmune thyroiditis (AIT). Objective: To determine whether L-T4 treatment prevents the clinical manifestation of AIT in euthyroid subjects with T1D. Design: Prospective, randomized, open, controlled clinical trial. Setting: Six tertiary care centers for pediatric endocrinology and diabetes. Patients: Of 611 children and adolescents with T1D, 89 individuals (14.5 percent) were identified with positive thyroid peroxidase antibodies (TPOAb), thyreoglobulin antibodies (TgAb), or both. Of these, 30 patients (age 13.3 +/- 2.1 years) met the inclusion criteria and were randomized to receive L-T4 (n = 16 patients) or no treatment (n = 14 patients). Intervention: L-T4 (1.3 microg/kg daily) was given for 24 months in the treatment group, followed by an additional observation period of 6 months in both groups. Main outcome measures: Thyroid gland volume (as determined by ultrasound), serum levels of thyrotropin, thyroid hormones, TPOAb, and TgAb were assessed every 6 months for 30 months. Results: Mean thyroid volume decreased in the treatment group after 24 months (- 0.60 standard deviation score, SDS) and increased in the observation group (+ 1.11 SDS, P = 0.0218). Serum thyrotropin, fT4, TPOAb, and TgAb levels were not significantly different in both groups during the entire study period. Hypothyroidism developed in three individuals treated with L-T4 and in four untreated patients (conversion rate, 9.3 percent per year). Conclusions: In this study in euthyroid patients with AIT and T1D, L-T4 treatment reduced thyroid volume but had no effect on thyroid function and serum autoantibody levels.