Objective. Oral solution and tablet formulations of Levo-Thyroxine (L-T4) are both used in the treatment of Congenital Hypothyroidism (CH). However, few studies and with a limited follow-up period have been published comparing these two formulations in children.
Design. The aim of this multicenter study was to compare the effectiveness of L-T4 oral solution (with ethanol as excipient) and tablet formulation in children with CH up to 3 years of age.
Methods. Children diagnosed with CH between 2006 and 2015 were enrolled and divided into two groups according to the L-T4 formulation used: solution in drops (Group D) or tablets (Group T). Auxological parameters, TSH and FT4 values and L-T4 dose were collected at diagnosis and at 15 days, 1, 3, 6, 12, 24 and 36 months of treatment. The Developmental Quotient at 1 and 3 years of age was evaluated using Griffiths’ Scale.
Results. 254 children were enrolled. 117 were treated with solution and 137 with tablets. Auxological parameters, dose and thyroid function values at diagnosis, 3, 6, 12, 24, 36 months were not significantly different. TSH at 15 days (p=0.002) and 1 month (p=0.009) was significantly reduced in group D. At 2-year follow-up, median TSH was significantly lower in group T (p=0.03). No statistical difference was detected between the median Developmental Quotient, however group D showed lower values in the language subscale at 12 months and in eye-hand coordination at 36 months.
Conclusions. Both therapeutic strategies are effective on treatment of CH. A higher risk of overtreatment in the first months of therapy seems to be associated with oral solution L-T4; therefore, a different strategy should be considered when starting and adjusting the dose. No negative effects in cognitive development were observed. The data obtained are encouraging but long-term follow-up is needed.
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