J Clin Endocrinol Metab. 2021 Nov 2:dgab798. doi: 10.1210/clinem/dgab798. Online ahead of print.
ABSTRACT
CONTEXT: The apparent increased incidence of congenital hypothyroidism (CH) is partly due to increased detection of transient disease.
OBJECTIVE: To identify predictors of transient CH (T-CH) and establish a predictive tool for its earlier differentiation from permanent CH (P-CH).
DESIGN: Retrospective cohort study of patients diagnosed with CH from 2006-2015 through Newborn Screening Ontario (NSO).
RESULTS: Of 469 cases, 360 (76.8%) were diagnosed with P-CH vs. 109 (23.2%) with T-CH. Doses of levothyroxine predicting T-CH were <3.9 mcg/kg at 6 months, <3.0 mcg/kg at 1 and 2 years, and <2.5 mcg/kg at 3 years. Descriptive statistics and multivariable logistic modeling demonstrated several diverging key measures between patients with T-CH versus P-CH, with optimal stratification at 1-year of age. Thyroid imaging was the strongest predictor (p<0.001). Excluding imaging, significant predictors in the first year of life included thyroxine dose/kg (p<0.001-0.002), rise in TSH above the reference interval during treatment (p=0.002), screening TSH (p=0.03), and a history of maternal thyroid disease (p=0.02). Based on the 1-year model without imaging, a risk score was developed to identify children with T-CH who may benefit from an earlier trial off therapy, to reduce excess medicalization and healthcare costs.
CONCLUSION: A levothyroxine dose of <3 mcg/kg at 1 and 2 years of age and <2.5 mcg/kg at 3 years of age can be predictive of T-CH. A novel risk score was developed that can be clinically applied to predict the likelihood of a successful trial off therapy for a given patient at 1 year of age.
PMID:34726229 | DOI:10.1210/clinem/dgab798
