Levothyroxine in euthyroid autoimmune thyroiditis and type 1 diabetes: a randomized, controlled trial.
BACKGROUND
Patients with type 1 diabetes (T1D) have an increased risk of autoimmune thyroiditis (AIT).


OBJECTIVE
Our objective was to determine whether levothyroxine (l-T(4)) treatment prevents the clinical manifestation of AIT in euthyroid subjects with T1D.


METHODS
We conducted a prospective, randomized, open, controlled clinical trial at six tertiary care centers for pediatric endocrinology and diabetes.


METHODS
Of 611 children and adolescents with T1D, 89 individuals (14.5%) were identified with positive thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb), or both. Of these, 30 patients (age, 13.3 +/- 2.1 yr) met the inclusion criteria and were randomized to receive l-T(4) (n = 16 patients) or no treatment (n = 14 patients).


METHODS
l-T(4) (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.


METHODS
Thyroid gland volume (as determined by ultrasound), serum levels of TSH, 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 sd score) and increased in the observation group (+ 1.11 sd score; P = 0.0218). Serum thyrotropin, free T(4), TPOAb, and TgAb levels were not significantly different in both groups during the entire study period. Hypothyroidism developed in three individuals treated with l-T(4) and in four untreated patients (conversion rate, 9.3% per year).


CONCLUSIONS
In this study in euthyroid patients with AIT and T1D, l-T(4) treatment reduced thyroid volume but had no effect on thyroid function and serum autoantibody levels.
Karges
Beate
B
Division of Pediatric Endocrinology and Diabetes, University Children's Hospital, University of Ulm, Eythstrasse 24, D-89075 Ulm, Germany. beate.karges@uniklinik-ulm.de
Muche
Rainer
R
Knerr
Ina
I
Ertelt
Waldemar
W
Wiesel
Thomas
T
Hub
Regine
R
Neu
Andreas
A
Klinghammer
Albrecht
A
Aufschild
Julia
J
Rapp
Andrea
A
Schirbel
Andreas
A
Boehm
Bernhard O
BO
Debatin
Klaus M
KM
Heinze
Eberhard
E
Karges
Wolfram
W
D000293:Adolescent; D001323:Autoantibodies / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D048909:Diabetes Complications / Q000188:drug therapy; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007223:Infant; D007453:Iodide Peroxidase / Q000276:immunology; D008297:Male; D011446:Prospective Studies; D013954:Thyroglobulin / Q000276:immunology; D013961:Thyroid Gland / Q000473:pathology; D013963:Thyroid Hormones / Q000097:blood; D013967:Thyroiditis, Autoimmune / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000627:therapeutic use*
D001323:Autoantibodies; D013963:Thyroid Hormones; D013972:Thyrotropin; D013954:Thyroglobulin; D007453:Iodide Peroxidase; D013974:Thyroxine