title: Are perinatal risk factors helpful in predicting and optimizing treatment strategies for transient hypothyroxinemia in very-low-birth-weight infants?
abstract: Transient hypothyroxinemia is common in premature infants and has been associated with intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), poor neurodevelopmental outcomes, and mortality. Recent trials have failed to show that supplemental thyroid hormone improves overall neurodevelopmental outcome. The objective of this article is too determine perinatal risk factors for transient hypothyroxinemia (TH). We studied a cohort of infants born between July 1993 and July 2000 who were less than 1500 g and who received a newborn screening for thyroid function ( n = 932). Total serum thyroxine (T(4)) was collected routinely on the fifth day of life. T (4) was correlated with gestational age (R = 0.59, p < 0.01). After controlling for potential confounding variables, gestational age, dopamine, and mechanical ventilation were found to be independently associated with low T (4) (overall model: r(2) = 0.41, p < 0.01). Number needed to treat (NNT) analysis showed treating all infants less than 27 weeks would lead to treating 6.3 infants for every one with a subsequent T(4) < 5 microg/dL. By combining gestational age and need for dopamine support, NNT = 2.4 for every one infant with subsequent T(4) < 5 microg/dL. Low gestational age, mechanical ventilation, and need for dopamine were associated with low T(4) levels and may be helpful in optimizing treatment strategies for TH.
authors.affiliation: Department of Neonatology, North Shore Medical Center, Miami, Florida, USA.
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Kantor Herring
authors.forename: Kathleen H
authors.initials: KH
authors.lastname: Leef
authors.forename: Robert G
authors.initials: RG
authors.lastname: Locke
authors.forename: John L
authors.initials: JL
authors.lastname: Stefano
authors.forename: Louis
authors.initials: L
authors.lastname: Bartoshesky
authors.forename: David A
authors.initials: DA
authors.lastname: Paul
mesh_terms: D000704:Analysis of Variance; D015331:Cohort Studies; D004298:Dopamine / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal; D008297:Male; D015999:Multivariate Analysis; D018743:Perinatal Care; D011237:Predictive Value of Tests; D011336:Probability; D012307:Risk Factors; D012720:Severity of Illness Index; D013960:Thyroid Function Tests; D013974:Thyroxine / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: D013974:Thyroxine; D004298:Dopamine