Predictive factors for remission in pediatric Graves' disease treated with antithyroid drugs: a retrospective study.

Pediatric Graves' disease (PGD) is a rare autoimmune disorder. Predictors of remission after antithyroid drug (ATD) therapy have been described, but their applicability in pediatric populations remains inconsistent. This study aimed to identify clinical and biochemical factors associated with remission in PGD. Retrospective observational study of children diagnosed with Graves' disease at a tertiary hospital in Portugal (2001-2021), all initially treated with ATD. Demographic, clinical, and biochemical data at diagnosis, as well as treatment characteristics, were analyzed. The primary outcome was "In Remission". Secondary outcomes included "Remission Experienced" and "Disease Not Active ≥1 Month". Comparative analyses, logistic regression, and receiver operating characteristic (ROC) curves were applied. Among 45,000 pediatric patients, 36 had PGD (prevalence 0.08%). Median age at diagnosis was 13.7 years; 81% were female, and 78% were pubertal. Methimazole was prescribed in 81%. Mean initial treatment duration (ITD) was 35 months, and 47% of patients underwent definitive therapy. At data collection, 18% of patients were in remission. Longer ITD (>24 months) was associated with remission; the optimal cutoff ITD was 51 months. Smaller thyroid volume and TRAb levels at diagnosis correlated with "Disease Not Active ≥1 Month". Thyroid volume ≥2.5-fold the upper limit of normal (ULN) and TRAb ≥7.055-fold the ULN reduced the likelihood of disease inactivity. Prolonged ATD therapy, smaller thyroid volume, and lower TRAb levels at diagnosis were associated with favorable outcomes in PGD. The optimal ITD (≥51 months) supports extended ATD therapy. Larger multicenter studies are warranted to confirm these results.