Background: Newborn (NB) screening programs show a wide variation in congenital hypothyroidism (CH) incidence along the years.
Objective and hypotheses: To describe CH incidence, etiology, associated malformations and Down Syndrome (DS) in children detected by our NB Screening Program. To search differences between permanent CH (PCH) and transient forms (TCH).
Method: We analyzed NB with positive screening results referred between April 1995 and December 2013. Two periods were analyzed: 19952004 (P1) and 20052013 (P2).CH was confirmed with TSH≥25 uUI/ml and T4<10 μg/dl. Incidence, etiology, associated malformations and DS were described. At three years of age, children were reevaluated to distinguish between PCH and TCH. Sex; delivery; birth weight; age, TSH, T4, levotiroxine dose (LTd) at start; and LTd at reevaluation were compared between PCH and TCH patients with eutopic thyroid gland. Students and Mann Whitney tests were used for continuous variables and Kruskal Wallis test for comparison between groups.
Results: Of 2.889.819 NB, 1331 were confirmed (F:M, 2:1) and treated with a mean LTd of 12.43±2.12 μg/kg/day. Median age at diagnosis was 18 (1426) days. Incidence was 1:2.171 (P1=1:2.425, P2=1:1.969). Twenty-three children had DS. Fifty-six children (3.45%) showed associated malformations. Of the total group, 675 children were reevaluated. Thirty-one (4.6%) had TCH and 644 (95.4%) had PCH. Etiologies of PCH forms were: athyreosis 161 (25.0%), ectopic disgenetic gland 368 (57.1%), eutopic disgenetic gland 14 (2.2%), and eutopic thyroid gland 101(15.7%). Patients with eutopic thyroid gland (n=132) showed TCH forms in 31 (23.5%) cases. LTd was the only variable that showed significant differences between PCH and TCH patients with eutopic thyroid gland (P<0.0001).
Conclusion: Last yearsCH incidence has increased in this program. Associated malformations were found in 3.45% of these CH patients. Transient forms showed a low frequency. Patients who required lower LTd at reevaluation were likely to have TCH forms.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology