“The ACA Medicaid expansion has significantly increased Medicaid enrollment and federal Medicaid expenditures. In FY2017, an estimated 12 million individuals were newly eligible for Medicaid through the ACA Medicaid expansion (i.e., expansion adults), and total Medicaid expenditures for the expansion adults were an estimated $71 billion. Enrollment for the expansion adults is projected to be 13 million in FY2026, and expenditures for the expansion adults are projected to be $120 billion in FY2026 (with the federal government paying $108 billion and states paying $12 billion).

“Between FY2014 and FY2015, the average per enrollee costs for expansion adults is projected to have increased from $5,511 to $6,365 (see Figure 2). States originally included adjustments to expansion adult per enrollee costs to account for pent-up demand, adverse selection, and expected higher health care needs. Per enrollee costs dropped to $5,965 in FY2016 and $5,813 in FY2017, as the effects of the pent-up demand were expected to end and evidence showed that the actual average costs for the expansion enrollees were lower than anticipated.

“As shown in Figure 2, the projected per enrollee costs for expansion adults also have been higher than the projected per enrollee costs for non-expansion adults. After FY2017, per enrollee costs for the expansion adults are still projected to remain higher than costs for the non-expansion adults but to grow at a similar rate.”

Source: U.S. Congressional Research Service. In Focus: Overview of the ACA Medicaid Expansion (IF10399; Dec. 3, 2018). https://crsreports.congress.gov/product/pdf/IF/IF10399