Endocrine Abstracts

Background: Long term remission in paediatric onset hyperthyroidism (HT) is low at 20–30% compared to 40–50% in adult onset HT. There are very few studies which report long-term follow-up of paediatric onset HT especially into adulthood and factors which can predict a need for definitive treatment in the long-term.

Objectives: To evaluate the long-term outcome of paediatric onset HT with follow-up into adulthood and identify any early predictors of a need for definitive therapy.

Methods: Retrospective analysis of those diagnosed to have HT under the age of 18 years and follow-up data available. At follow-up, comparison was made by categorising them into three groups: those who underwent definitive therapy (DT) i.e Thyroidectomy/Radioactive iodine (RAI), those who remained on Antithyroid drugs- ADT (MT) and those achieved complete remission (CR).

Results: In total of 61 patients (49 females, 12 males) were identified to fulfil criteria for the study. Median age at diagnosis was 15.1 years (range: 3.6–18) with 34% between 16–18 years. All 61 patients were treated with ATD at diagnosis. Duration of first course of ATD varied from < 1 year in 7%, 1–2 years in 26%, >2 years in 46% and ATD never discontinued in 21%. 69% of those with < 1 year ATD relapsed compared to 79% with ATD > 2 years (median duration of treatment 31.5 m [range 24–96 m]).

At follow-up, median duration since diagnosis was 8.75 yrs (range 2.0–20.7 yrs) and median age at follow-up was 23.2 yrs (5.6–36 yrs). 32% (20/61) had undergone definitive treatment (DT group) – 16% (n=10) RAI and 16% (n=10) surgery, 36% (22/61) still on ATD (MT group) whilst 32% (19/61) had undergone full remission (CR group). Comparison between the three groups did not identify any statistically significant difference for predictor factors at diagnosis including age, T4 and free T4 levels, Thyroid peroxidise antibody levels and duration of first course of CBZ treatment.

Conclusion: Long-term complete remission of paediatric onset HT in our study was 32%. There were no predictors identified that could help predict long-term outcome, especially into adulthood.