J Clin Endocrinol Metab. 2023 Jun 3:dgad333. doi: 10.1210/clinem/dgad333. Online ahead of print.
ABSTRACT
CONTEXT: The lack of syndrome-specific reference ranges for thyroid function tests (TFT) among pediatric patients with Down syndrome (DS) results in an overestimation of the occurrence of hypothyroidism in this population.
OBJECTIVES: a) to outline the age-dependent distribution of TFT among pediatric patients with DS; b) to describe the intraindividual variability of TFT over time; c) to assess the role of elevated TSH in predicting the future onset of overt hypothyroidism.
DESIGN: Retrospective, monocentric, observational analysis.
PATIENTS: We included 548 Down patients (0-18 years) longitudinally assessed between 1992 and 2022. Exclusion criteria: abnormal thyroid anatomy, treatments affecting TFT and positive thyroid auto-antibodies.
RESULTS: We determined the age-dependent distribution of TSH, FT3 and FT4 and outlined the relative nomograms for children with DS. Compared to non-syndromic patients, median TSH levels were statistically greater at any age (p < 0.001). Median FT3 and FT4 levels were statistically lower than controls (p < 0.001) only in specific age classes (0-11 for FT3, 11-18 years for FT4).TSH levels showed a remarkable fluctuation over time, with a poor (23-53%) agreement between the TSH centile classes at two sequential assessments.Finally, the 75th centile was the threshold above which TSH values predicted future evolution into overt hypothyroidism with the best statistical accuracy, with a satisfactory negative predictive value (NPP, 0.91), but poor positive (P) PV (0.15).
CONCLUSIONS: By longitudinally assessing TFT in a wide pediatric DS population, we outlined the syndrome-specific reference nomograms for TSH, FT3 and FT4 and demonstrated a persistent upward shift of TSH compared to non-syndromic children.
PMID:37279507 | DOI:10.1210/clinem/dgad333
