title: Earlier re-evaluation may be possible in pediatric patients with eutopic congenital hypothyroidism requiring lower L-thyroxine doses.
abstract: OBJECTIVE
  The incidence of congenital hypothyroidism (CH) has increased in several countries. Lower cut-off in screening programs have led to an increase in the proportion of transient hypothyroidism (TH) cases diagnosed, leading to debate on the associated clinical and economic impact. This study aimed to identify factors that would allow discrimination between TH and permanent CH (PH) in patients with a eutopic thyroid gland.
  
  
  METHODS
  Sixty-six patients with CH from 3 different hospitals were studied: 26 cases of TH, and 40 cases of PH. Laboratory findings and clinical parameters were analysed in 56 patients with eutopic thyroid gland.
  
  
  RESULTS
  Initial serum thyroid stimulating hormone levels and L-thyroxine dose at 12 and 24 months of age were significantly higher in PH than TH patients with a eutopic thyroid gland. The area under the curve for the 12-month and 24-month dose for the prediction of TH in eutopic CH was 0.799 (95% confidence interval [CI], 0.678-0.919; P<0.001) and 0.925 (95% CI, 0.837-1.000; P<0.001), respectively. The optimum 12-month and 24-month dose in predicting TH is 3.25 µg/kg (12-month: sensitivity, 87.1%; specificity, 68.0%; 24-month: sensitivity 93.5%, specificity 88%).
  
  
  CONCLUSIONS
  Infants with CH requiring lower L-thyroxine doses (<3.25 µg/kg) are likely to have TH, and thus might be re-evaluated at 12 months or 24 months rather than 3 years of age.
authors.affiliation: Department of Pediatrics, The Catholic University of Korea, St. Paul's Hospital, Seoul, Korea.
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Cho
authors.affiliation: Department of Pediatrics, The Catholic University of Korea, Bucheon St. Mary's Hospital, Bucheon, Korea.
authors.forename: Gyung Sun
authors.initials: GS
authors.lastname: Cho
authors.affiliation: Department of Pediatrics, The Catholic University of Korea, St. Vincent's Hospital, Suwon, Korea.
authors.forename: So Hyun
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Pediatrics, The Catholic University of Korea, Yeouido St. Mary's Hospital, Seoul, Korea.
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Jung
authors.affiliation: Department of Pediatrics, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Korea.
authors.forename: Byung Kyu
authors.initials: BK
authors.lastname: Suh
authors.affiliation: Department of Pediatrics, The Catholic University of Korea, St. Vincent's Hospital, Suwon, Korea.
authors.forename: Dae Gyun
authors.initials: DG
authors.lastname: Koh
keywords: Congenital hypothyroidism; Thyroid gland; Thyroxine