ESPE Abstracts (2018) 89 P-P3-391

Levothyroxine Treatment of Subclinical (SH) and Overt (OH) Hypothyroidism in Children with Autoimmune Hashimoto Thyroiditis (AHT): A Retrospective Study in Regard with TSH and Free T4 (FT4) at Diagnosis

Sofia Leka-EmirIa, Vassilios Petroua, Cathrine Evangelopouloua, Maria Kafetzib, Aspasia Fotinoub, Elpis Vlachopapadopouloua & Stefanos Michalacosa

aDivision of Endocrinology-Growth and Development, ‘P&A KYRIAKOU’ Children’s Hospital, Athens, Greece; bDivision of Biochemistry-Hormonology, ‘P&A KYRIAKOU’ Children’s Hospital, Athens, Greece

Objectives: Assess the dose of levothyroxine in relation to TSH and FT4 levels at diagnosis of AHT in children with SH and OH.

Methods: Eighty eight children (69 girls) with AHT were devised in regard with TSH and FT4 at diagnosis [SH-FT4 >0.9 ng/dl: Group 1: TSH: 4.5-7 mU/l, Group 2: TSH: 7-10 mU/l, Group 3: TSH: >10 mU/l and OH: Group 4: TSH>10 mU/l and FT4 ≤0.9 ng/dl]. Mean L-T4 dose was reported in μgr/Kg per day at diagnosis and at 2.4 years of follow up and TSH targeted levels under treatment were ≤4 mU/l.

Results: Mean age at diagnosis was 9.7 years (S.D., 2.6). Main characteristics are shown in table 1. At diagnosis, FT4 levels were significantly lower only in OH with regard to SH groups. Similarly, L-T4 dose in OH was significantly higher as opposed to SH groups. At 2.4 yrs (S.D., 1.2) of treatment all patients were euthyroid and TSH and FT4 levels did not differ significantly between groups. L-T4 dose was significantly higher in OH as opposed to group 1 and group 2 but not group 3.

Table 1 Data are shown as means (S.D.).
Group 1 (n=26)Group2 (n=26)Group 3 (n=21)Group 4 (n=15)*P
Age (yrs)10.2 (2.2)10.4 (2.6)9.2 (2.8)8.6 (2.9)
Height z-score0.68 (1.1)0.47 (1.2)0.25 (0.9)0.48 (0.8)
BMI z-score0.83 (0.8)0.78 (0.9)0.88 (0.9)1.04 (1.1)
TSH (mU/l)5.6 (0.6)8.1 (0.9)16.5 (12.9)57.7 (46.4)*
FT4 (ng/dl)1.23 (0.2)1.18 (0.1)1.16 (0.1)0.8 (0.1)*
L-T4 (μg/Kg per day)1.1 (0.35)1.03 (0.27)1.38 (0.37)1.91 (0.9)*
AT FOLLOW UP (2.4 yrs)
Age (yrs)12.3 (1.9)13.1 (2.5)11.6 (3.2)10.7 (2.8)
Height z-score0.69 (1.0)0.46 (1.1)0.43 (0.80.76 (0.9)
BMI z-score0.65 (0.8)0.65 (0.8)0.92 (0.9)0.89 (0.9)
TSH (mU/l)2.5 (1.3)2.8 (1.3)2.2 (1.2)2.1 (0.9)
FT4 (ng/dl)1.4 (0.2)1.3 (0.2)1.3 (0.2)1.2 (0.2)
L-T4 (μg/Kg per day)1.2 (0.3)1.2 (0.3)1.5 (0.4)1.9 (1.2)*
*One-Way Analysis of variance (ANOVA), P<0.05.

Conclusions: At diagnosis, L-T4 needs are significantly lower in SH patients as opposed to OH patients. At 2.4 years, children with OH receive significantly higher LT-4 doses than those with SH and TSH < 10 mU/l but similar with those of SH and TSH >10 mU/l.