Abstract
OBJECTIVE: The purpose of this work was to estimate the incidence of medically treated thyroid disease in children with Down syndrome enrolled in Tennessee Medicaid (TennCare) during 1995-2005 and to determine whether rates increased after rerelease of American Academy of Pediatrics guidelines in 2001. PATIENTS AND METHODS: We conducted a population-based retrospective cohort study in which we identified children with Down syndrome by using TennCare files and birth certificates. We included 1- to 18-year-olds who were continuously enrolled in TennCare and did not fill a prescription for thyroid medication during a 90-day prestudy period. The rate of medically treated thyroid disease (prescription filled for thyroid medication) was the main outcome. We used Poisson regression to estimate rates of medically treated thyroid disease according to study year, age, gender, race, region of residence, and payer type. RESULTS: During the 11-year study period, 1257 children with Down syndrome (28% black, 72% white) met inclusion criteria. Overall, 10.8% filled a new prescription for thyroid medication. Rates of medically treated thyroid disease per 1000 child-years were 13.25 (1995-1997), 13.34 (1998-1999), 13.62 (2000-2001), 22.37 (2002-2003), and 22.51 (2004-2005). After adjusting for child age and race, there was an increased rate of medically treated thyroid disease in 2002-2003 and 2004-2005 compared with 1995-1997. In a comparison cohort of children without Down syndrome, there was a smaller increase in the rate of medically treated thyroid disease when comparing 2002-2003 and 2004-2005 with 1995-1997. CONCLUSIONS: Over the 11-year period, 10.8% of children with Down syndrome filled a new prescription for a thyroid medication. A 73% increase in the incidence of medically treated thyroid disease occurred after rerelease of American Academy of Pediatrics guidelines, which may have influenced screening.