Price Increases Versus Upcoding As Drivers Of Emergency Department Spending Increases, 2012-19.

Recent studies document a substantial increase in emergency department (ED) spending in the past decade, even though the number of ED visits per capita has remained relatively stable. Price increases and upcoding are sometimes cited as possible explanations, but their relative impacts are not known. We analyzed Blue Cross Blue Shield claims for patients of all ages who received care in EDs in five states in 2012 and 2019. We used estimates from spending regressions and regressions explaining coding intensity to decompose changes in spending between 2012 and 2019 into components attributable to price increases, changes in patient characteristics or treatment intensity, and upcoding. Prices accounted for at least half of the increase in ED spending per visit for four of the five states we examined. Increases in spending attributable to upcoding were notable but generally not as large. Future research should explore the associations between local market conditions, such as consolidation and ownership type, and both price increases and upcoding.