A practical gestational age-based algorithm for timely detection of hypothyroidism in premature infants.

Abstract

To assess utility and accuracy of a gestational age-based screening targeting premature infants to detect congenital hypothyroidism. A prospective cohort study was conducted in infants <35 weeks' gestational age with clinical outcomes at 2-3 years of age. Patients received newborn screenings at 24 hours and 10-14 days of life. Free T4 (FT4) and thyroid-stimulating hormone (TSH) levels were measured at one month of life and repeated based on algorithm by corrected gestational age. Among infants <35 weeks gestation (n = 938), the incidence of hypothyroidism requiring treatment was 1:58. TSH levels at one month of age was predictive of treatment (AUC 0.96, 95% CI 0.88-1). The optimal TSH threshold of 8 mIU/L (8 µU/ml) increased the specificity to 0.97 and sensitivity to 0.88. Following initiation of treatment forhypothyroidism during NICU hospitalization,43.8% (n = 7) were diagnosed with permanent congenital hypothyroidism. Our study supports a gestational age-based screening algorithm for early detection of hypothyroidism in premature infants.