Impact of a multi-payer full-risk model on preserving primary care access for traditional medicare beneficiaries.

Amid growing primary care shortages and increased use of value-based care (VBC), we evaluated whether adopting a multipayer, full-risk VBC model for Traditional Medicare (TM) and Medicare Advantage beneficiaries-supported by an enablement organization-affected primary care providers' (PCPs) acceptance of new patients with TM insurance. Using a difference-in-differences analysis of 2019-2023 claims, we compared 2 groups of PCPs with at least 50 TM patients in their panels: 208 PCPs who received support to adopt a VBC model for TM and Medicare Advantage patients in 2022, and 3657 similar PCPs who maintained their existing payment models.Between the preadoption period and 2023, access to new patient visits for patients with TM insurance declined more for nonadopters than adopters. Primary care providers' in the VBC group saw, on average, 8 more new TM patients annually than nonadopters. This change is sizable relative to their 22.6 new TM patients in 2023. Additionally, the VBC group kept their panels open to new patients with TM insurance for 0.7 more months per year, on average, than nonadopters, relative to preadoption. These findings suggest that a VBC model with support may help sustain access to primary care for TM beneficiaries, even as overall availability declines.