Post-acute care and ACOs - who will be accountable?

Objective: To determine how the inclusion of post-acute evaluation and management (E&M) services as primary care affects assignment of Medicare beneficiaries to accountable care organizations (ACOs).

Data sources: Medicare claims for a random 5 percent sample of 2009 Medicare beneficiaries linked to American Medical Association Group Practice data identifying provider groups sufficiently large to be eligible for ACO program participation.

Study design: We calculated the fraction of community-dwelling beneficiaries whose assignment shifted, as a consequence of including post-acute E&M services, from the group providing their outpatient primary care to a different group providing their inpatient post-acute care.

Principal findings: Assignment shifts occurred for 27.6 percent of 25,992 community-dwelling beneficiaries with at least one post-acute skilled nursing facility stay, and they were more common for those incurring higher Medicare spending. Those whose assignment shifted constituted only 1.3 percent of all community-dwelling beneficiaries cared for by large ACO-eligible organizations (n = 535,138), but they accounted for 8.4 percent of total Medicare spending for this population.

Conclusions: Under current Medicare assignment rules, ACOs may not be accountable for an influential group of post-acute patients, suggesting missed opportunities to improve care coordination and reduce inappropriate readmissions.