Hypothyroidism Prevalence in Children Aged 0 to 17 Years in the United States: A Real-World Study Using 2 National Claims Databases, 2013-2022.

OBJECTIVE: Pediatric hypothyroidism is an endocrine disorder where early thyroid replacement therapy is recommended to support healthy development. This study characterized prevalence and treatment patterns of pediatric hypothyroidism among children in the US. METHODS: Children aged 0-17 years with hypothyroidism were identified from two large US claims databases from 2013 to 2022, using age-specific algorithms based on diagnosis and prescription claims. Annual prevalence of hypothyroidism and treated hypothyroidism were analyzed separately by database and as a pooled dataset, and stratified by age group, sex, and calendar year. Two-sample tests of proportion were used to compare prevalence across groups. RESULTS: Among 7,214,633 children, the overall hypothyroidism prevalence (per 1000 children) was 3.49 in 2022. From 2013 to 2022, annual hypothyroidism prevalence (per 1000 children) increased by 43% in children <1 year (0.62 to 0.88) and by 33% in children aged 1-3 years (0.70 to 0.94), but decreased by 9% to 18% in children aged 4-17 years. Prevalence was higher in female than male children, and differences between sexes increased with age. In 2022, approximately two-thirds of children with hypothyroidism received thyroid replacement therapy. Female children were significantly more likely than males to receive treatment, with the largest difference among those aged 8-11 years (70.1% vs 61.5%). CONCLUSION: Distinct age- and sex-dependent trends in pediatric hypothyroidism prevalence were observed over time. A substantial subpopulation of patients did not receive treatment despite known developmental risks. Enhanced efforts to identify and treat pediatric hypothyroidism are warranted to ensure optimal developmental outcomes for affected children.