Payment Discrepancies and Access to Primary Care Physicians for Dual-eligible Medicare-Medicaid Beneficiaries

Abstract

Importance: Dual-eligible Medicare-Medicaid beneficiaries represent 1-in-5 Medicare beneficiaries, but providers receive less than 100% of the Medicare fee for them because of reimbursement caps in many states.

Objective: To examine how this payment differential impacts the availability of primary care physicians (PCPs) for dual vs. non-dual Traditional Medicare (TM) beneficiaries, we leverage the Affordable Care Act (ACA) primary care fee bump that temporarily eliminated this differential in 2013-2014.

Design: We used the Medicare Physician and Other Supplier Public Use File (2012-2017) to enumerate TM beneficiaries each provider billed for annually by dual status and calculate dual caseloads as a percentage of a physicians’ TM patients. We examined differences in PCPs’ Medicare dual caseloads in states with and without dual reimbursement differentials using multivariate regression models, adjusted for provider and area-level traits. We also used a triple difference approach to examine the effects of temporary and extended fee bumps vs. no bump on PCP’s dual caseloads compared with caseloads of selected specialists unexposed to the fee bump.

Setting: Traditional Medicare

Participants: PCPs and a comparison specialty group of cardiologists, orthopedic surgeons, and general surgeons

Exposure: State dual reimbursement policies and changes over time due to the ACA fee bump

Main outcome measures: Medicare dual caseloads of at least 20% (the national average) or 10% (81% of PCP’s).

Results: In 2012, prior to the fee bump, PCPs in states with lower reimbursement for duals vs. minimal differences were less likely to have a dual caseload of at least 10% (e.g., difference=-4.83 percentage points (pp) (95% CI: -7.22 to -2.44) for states with temporary fee bumps). Despite the constant proportion of dual beneficiaries, the proportion of PCPs with dual caseloads of at least 10% or 20% decreased between 2012-2017, and the fee increase was not consistently associated with increases in the likelihood of PCPs exceeding these thresholds.

Conclusions: Pre-ACA, state reimbursement caps for dual-eligibles were associated with a lower proportion of duals on PCPs’ Medicare panels. Despite the ACA’s fee bump, the proportion of physicians treating duals declined over time, raising concerns of worsening access for duals.