130 Retrospective analysis of patients with transient hypothyroxinemia of prematurity: Single center experience. (11th October 2021)

• Record Type: Journal Article
• Authors: Yılmaz, Aslan; Altun, Ilayda; Ozer, Yavuz; Turan, Hande; Cakar, Aydilek Dagdeviren; Acar, Hazal Cansu; Perk, Yıldız; Vural, Zekeriye Mehmet; Ercan, Oya; Evliyaoglu, Olcay
• Is Part Of: Archives of disease in childhood. Volume 106(2021)Supplement 2
• Page Start: A56
• Page End: A56
• Publication Date: 2021-10-11
• Subjects: Children -- Diseases -- Periodicals; Infants -- Diseases -- Periodicals; 618.920005
• DOI: 10.1136/archdischild-2021-europaediatrics.130
• Languages: English
• ISSNs: 0003-9888

Abstract

Abstract : Transient hypothyroxinemia of prematurity (THOP) is defined as low level of circulating thyroid hormones, despite low or normal thyroid stimulating hormone (TSH) level and detected in 35-50% of premature infants. There is no consensus on the management of THOP.Our aim was to evaluate the incidence and clinical characteristics of patients with THOP in the tertiary neonatal intensive care unit (NICU), and the rate of L-T4 treatment. Premature newborns delivered at 24-34 wks of gestation, followed in NICU of Cerrahpasa Medical Faculty between January 2014-December 2019 were involved. Thyroid function tests were performed between 10-20 postnatal days. Thyroid function tests were evaluated according to the gestational age references. Among 181 infants, 52.5% (n=95) were male. Mean birth weight was 1424.85±522.58 gr. Mean duration stay in NICU was 45.2±28.7 days. Thyroid function tests were euthyroid in 47.5% (n=86) of the patients. Hypothyroxinemia of prematurity, primary hypothyroidism and subclinical hypothyroidism were diagnosed in 45.8% (n=83), 4.9% (n=9) and 1.6% (n=3), respectively. The infants were subdivided into gestational age groups as follows: 24–27 wk, 28 –30 wk, 31–34 wk. Sixty four%(n=53) of the infants with THOP were male. Mean birth weight and gestational week were significantly lower in the hypothroxinemic group than euthyroid group. The frequency of THOP was 70% (n=26) in 24-27 wk; 58% (n=28) in 28-30 wk and 35% (n=29) in 31-34 wk. L-T4 was given to 43% (n=36) of the patients with THOP. Treatment initiation rate was 62% (n=16) in 24-27 wk, 54% (n=15) in 28-30 wk and 17% (n=5) in 31-34 wk. As the gestational week increased; incidence of THOP and the rate of treatment initiation decreased. Serum FT4 levels were lower in the treated group, but no difference was observed in terms of TSH levels. The low limit of FT4 to start treatment was determined as 0.72 ng/dl (specificity 100%, sensitivity 33%). It was observed that the need for supportive treatment was more in the treated group. In our study, it was observed that the prevalence of THOP increased as the gestational week and birth weight decreased. In addition, it was found that the rate of patients with low FT4 level requiring L-T4 treatment increased as the gestational week decreased and comorbid diseases increased.