Transient vs Permanent Congenital Hypothyroidism in Ontario, Canada: Predictive Factors and Scoring System

Abstract

Context: The apparent increased incidence of congenital hypothyroidism (CH) is partly due to increased detection of transient disease. Objective: This work aims to identify predictors of transient CH (T-CH) and establish a predictive tool for its earlier differentiation from permanent CH (P-CH). Methods: A retrospective cohort study was conducted of patients diagnosed with CH from 2006 to 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 less than 3.9 μg/kg at age 6 months, less than 3.0 μg/kg at ages 1 and 2 years, and less than 2.5 μg/kg at age 3 years. Descriptive statistics and multivariable logistic modeling demonstrated several diverging key measures between patients with T-CH vs P-CH, with optimal stratification at age 1 year. Thyroid imaging was the strongest predictor (P