Thyroid Hormone Use in the United States, 1997-2016

Thyroid disorders are among the most commonly treated conditions by the United States health care system. The number of patients reporting thyroid hormone use has increased in recent years, but it is unknown if there have been differential increases in the number of treated individuals within different demographic groups. Previous research has also not evaluated how expenditures for different thyroid hormone medications have changed in recent years.

Using data from the 1997 through 2016 Medical Expenditure Panel Survey, we calculated the proportion of adults reporting thyroid hormone prescriptions by 3 demographic variables (age, sex, and race) and determined expenditures from thyroid hormone prescriptions by medication type (overall, generic, Synthroid or Cytomel, and other brand).

Between 1997 and 2016, the proportion of adults who reported thyroid hormone use increased from 4.1% (95% CI, 3.7-4.4) to 8.0% (95% CI, 7.5-8.5). Most of the growth in thyroid hormone use occurred among adults aged >65, and use was also more common among females and non-Hispanic whites. Expenditures from thyroid hormones increased from $1.1 billion (95% CI, 0.9-1.3) in 1997 to $3.2 billion dollars (95% CI, 2.9-3.6) in 2016. Generic thyroid hormone prescriptions comprised 18.1% of all thyroid hormone prescriptions in 2004 (95% CI, 15.8-20.4) and 80.8% of all thyroid hormone prescriptions (95% CI, 78.4-83.2) in 2016.

Thyroid hormone use nearly doubled over the last 20 years, and increased use was associated with being older, female, and non-Hispanic white. During the same time period, thyroid hormone expenditures almost tripled.