Long-term outcomes of anti-thyroid drug treatment in childhood-onset Graves' disease

Objective: Outcomes of childhood-onset Graves' disease (GD) and suggested duration of anti-thyroid drug (ATD) therapy have been controversial. This study aimed to determine long-term outcomes following ATD therapy, including remission and relapse rates. Design, patients and measurements: A retrospective study of 265 paediatric patients with GD who were initially treated with ATD was conducted. Long-term outcomes were analysed. Results: Median (IQR) age at diagnosis was 11.5 (9.4, 13.7) years. Duration of ATD treatment was 4.3 (2.3, 6.7) years and time since diagnosis to the enrolment was 7.1 (3.8, 10.9) years. There were 77, 93 and 95 patients who underwent definitive treatment, had ATD discontinuation, and were still being treated with ATD, respectively. The remission rate was 21% (56 out of 265 patients) and relapse rate was 40% (37 out of 93 patients). Cumulative incidence of first remission increased with the duration of ATD treatment with maximum remission rate at 5.3 years following ATD therapy. Among patients who experienced relapse, approximately 50% had disease relapse which occurred within 1 year after ATD discontinuation. Patients with goitre size of less than 3.5 cm, thyroid-stimulating hormone receptor antibody of less than 10 IU/L, no ophthalmopathy at diagnosis and methimazole dose requirement of less than 0.25 mg/kg/day at 1 year after treatment were more likely to achieve remission. Conclusions: Remission rate of childhood-onset GD was relatively low following ATD treatment. Longer-term ATD therapy was associated with increased remission rate. Approximately 50% of patients with relapse had disease relapse within 1 year following ATD discontinuation.