Subclinical Hypothyroidism In Pediatric Population Treated With L-Thyroxine: A Retrospective Observational Analysis on 2001–2014 Administrative Data


      The aim of this study is to define and characterize pediatric population (0-13 years old) with Subclinical Hypothyroidism (SH) treated with levothyroxine, as regards treatment approaches and comorbidities, from 2004 to 2014.


      From the CINECA ARNO Observatory (about 17 million Italian citizens), a record linkage of free filled drug prescriptions, hospitalizations and specialist procedures data was performed and a cohort of children (0-13 years) with SH treated with low dosage levothyroxine was selected in 2004 and followed-up from the first levothyroxine prescription (index date) over 10 years or until the 14th birthday (excluded). Patients were levothyroxine-free the 3 years before the index date.


      From a population of 380,308 pediatric patients with treated SH, a cohort of 48 naïve children was selected. The incidence rate in 2004 was 12.6 x100.000 (62.5% females). New users of levothyroxine were mostly 11, 12 and 13 years old (37.5%). Mean age of start therapy was 7. 6 years (SD 4.5 years). At the onset of treatment, on average 4,109 µg/year was prescribed (SD 2,273 µg/year). No important dosage changes were assessed with the growth. The majority of children with SH (70.8%) was treated for more than one year, and for on average 1.85 years (SD 1.82). Males are treated longer than females (2.06 vs 1.73 years). Specifically, 18.7% received levothyroxine for one or two years, while 10.5% for at least 4 years. 89% of children with more than one year of treatment received continuous prescriptions during the follow-up.


      This is the first study that provides epidemiological data about SH in Italian children and pre-adolescents. It gives information about the real therapeutic approach of SH. It is a starting point for health governance to improve the clinical care and the disease management.