Beneficiary leakage occurs when a beneficiary receives healthcare services from non-participating ACO providers. Beneficiary assignment is a two-step process where CMS attributes individuals (retrospectively for MSSP and prospectively for Pioneer) to the ACO based on whether they received a plurality of their primary care from a primary care physician (PCP) participating in a Medicare ACO. The second step allows beneficiaries to be assigned to specialists, if the plurality of their primary care charges were not attributed to a PCP affiliated with a Medicare ACO.
Harvard Medical School researchers evaluated 2010 and 2011 Medicare claims data from 145 participating Medicare ACOs. Key findings include:
- Two-thirds of beneficiaries sought outpatient specialty care from providers outside of their ACO, and 8.7 percent of beneficiaries saw PCPs unaffiliated with their ACO.
- Two-thirds of beneficiaries attributed to an ACO in 2010 or 2011 were assigned to the same ACO across both years.
- Less than 40 percent of Medicare outpatient billings by physicians participating in a Medicare ACO were associated with an assigned beneficiary. These issues threaten the sustainability of Medicare ACOs, as they make it challenging for participating organizations to effectively manage and coordinate care if their assigned patient population is not stable. Notably, beneficiary leakage and assignment varied significantly across the different Medicare ACOs. ACOs that were more primary care-oriented had higher beneficiary assignment stability across 2010 and 2011 in comparison to ACOs that were more specialty-focused. Furthermore, beneficiaries with fewer conditions and office visits as well as beneficiaries with ESRD, disabilities, Medicaid coverage, and high spending were less likely to be assigned to the same ACO across 2010 and 2011. In addition, leakage for outpatient specialty care was more prevalent among high-cost beneficiaries as well as among smaller ACOs in comparison to larger ACOs.
The American Hospital Association (AHA) recently submitted a letter in response CMS’ RFI on the evolution of ACOs outlining their concerns with the Medicare ACO programs. In the letter, AHA encouraged CMS to implement a voluntary sign-up process to allow patients to opt-in to the ACO. Beneficiary enrollment could reduce leakage and enhance their engagement in the program. Recently, MedPAC also has emphasized the need to adjust the current beneficiary assignment methodology and address the lack of beneficiary incentives to seek care within a Medicare ACO.
CMS is likely to release a proposed rule addressing these and other issues later this year.
View the full JAMA story.