Subclinical hypothyroidism in paediatric population treated with levothyroxine: a real-world study on 2001–2014 Italian administrative data

Abstract

ObjectiveTo estimate the prevalence of subclinical hypothyroidism (SH) among children, by using levothyroxine low dosage as disease proxy, and to describe prescription pattern.DesignAn historical cohort study was performed through administrative databases of 12 Italian Local Health Units covering 3,079,141 inhabitants. A cohort of children (aged 0–13 years) was selected in the period 2001–2014. A subgroup of new users (aged 0–9 years) was identified and followed up for 5 years.MethodsThe prevalence was provided as mean value of the whole period, as annual trend, by patient gender and age. Demographic details, information on levothyroxine dosage, comorbidities and co-medications were provided. Therapy duration and medication persistence were evaluated among new users.Results644 children treated with levothyroxine low dosage was selected, with a mean annual prevalence of 0.20 per 1000 children. The temporal trend of prevalence was stable, with a slight reduction in the 2005–2008. Prevalence by age showed an increase after 10 years. Patients were treated with an average annual dose of 4290 µg/year and 66.9% of children were affected by comorbidities. Among 197 new users, 62.9% received therapy only for one year, whereas out of those treated two or more years, 89.0% resulted persistent to the therapy.ConclusionsThis study provides real-world epidemiology of SH among children, and it depicts the clinical and therapeutic characteristics of these subjects. Its findings showed that the SH treatment of this disorder was widely variable, also due to lack of evidence concerning paediatric population.

The effect of subclinical hypothyroidism on body composition parameters in children

“…Recent studies in adult populations showed that SH is associated with increased cardiovascular risk, albuminuria, elevation in total cholesterol and low‐density lipoprotein, systemic hypothyroid symptoms or neuropsychiatric symptoms (eg, depression and negativism) 3,6‐8 . Unfortunately, there are a few studies including children with SH 9‐13 . Some studies indicate that LT4 treatment may be considered in children with MSH in the presence of positive anti‐thyroid autoantibodies, subtle proatherogenic metabolic abnormalities and persistent TSH elevation.…”

Levothyroxine in Children

“…A large database analysis, conducted using records of more than 1 million paediatric outpatients, found that TSH was 5.5-10 mIU/L in 2.9%, and >10 mIU/L in 0.4% [14]. A recent study of more than 3 million children in Italy using administrative health databases for the years 2001-2014 found an annual prevalence of subclinical hypothyroidism (based on receipt of a low dose of LT4) of 1 case per 5000 children [15]. The annual prevalence remained relatively stable over time and tended to increase at age >10 years.…”

Subclinical Hypothyroidism in Pediatric Age: How Important Is Autoimmunity?

“…The pattern of SHT is characterized by a thyroid-stimulating hormone (TSH) value above the upper limit of the reference range in the presence of normal free triiodothyronine (FT3) and free thyroxine (FT4) levels [ 3 ]. The estimated prevalence of SHT in adults is 4-20% and in pediatric age seems to be less than 2%, despite the scarcity of epidemiologic studies in this age group [ 4 , 5 ].…”