Prevalence, presentation and clinical evolution of Graves' disease in children and adolescents with type 1 diabetes mellitus.

AIMS: To ascertain the prevalence of Graves' disease (GD) in 1,323 Caucasian children with type 1 diabetes mellitus (T1DM), and to compare the course of GD in T1DM patients with the one observed in 109 Caucasian peer patients with GD but without T1DM (group B). Results: Only 7 patients (0.53%) of the T1DM series also presented with GD (group A)which was diagnosed many years after diabetes presentation. At GD diagnosis, the prevalence of preclinical hyperthyroidism was higher in group A (p = 0.0001), whereas serum TSH receptor antibodies (TRABs) were higher in group B (p = 0.04). The subsequent course with methimazole therapy and after its withdrawal was very similar in both groups. Conclusions: GD prevalence in T1DM patients was 0.53%, i.e. almost identical to the one reported in the general population. GD was diagnosed many years after T1DM presentation. At GD diagnosis, the clinical picture was milder and TRAB serum levels were lower in diabetic patients. Preclinical diagnosis and early treatment of GD were not associated with better responsiveness to therapy. Screening programs based on periodical TRAB assessments are not useful in T1DM.