Why the increase? Examining the rise in prescription medication expenditures in the United States between 2011 and 2020.

The objective of this cross-sectional analysis was to identify determinants of increasing medicine expenditures in the US between 2011 and 2020. Prescription medication expenditures from the 2011-2020 Medical Expenditures Panel Survey (MEPS) were used to calculate total annual medication expenditures by payer categories (Out-of-pocket, Medicare, Medicaid, TRICARE/Veterans Administration/CHAMPVA (TVAC), Other Government Sources, Private Insurance, and Other Sources). From here, expenditures were stratified by therapeutic category using Multum Lexicon Drug Class to examine trends in expenditures by therapeutic area. Linear regression was used to identify temporal trends in medication expenditures. From 2011 to 2020, total annual prescription medication expenditures rose from $341.49 to $473.12 billion per year with metabolic agents being the most costly category. Among the metabolic agents, antidiabetic agents were the most costly therapeutic area, with an increasing trend observed from $27.15 to $89.17 billion over the same period. Medicare, Medicaid, Private Insurance, TVAC, and Other Sources also saw an increasing trend in antidiabetic agent expenditure, while no trend was observed for Out-of-pocket and Other Government Sources. Insulin had the highest expenditure among antidiabetic agents. Further studies are warranted to explore specific factors contributing to the increasing trend.