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

Background: Physicians often receive lower payments for dual-eligible Medicare-Medicaid beneficiaries versus nondual Medicare beneficiaries because of state reimbursement caps. The Affordable Care Act (ACA) primary care fee bump temporarily eliminated this differential in 2013-2014.

Objective: To examine how dual payment policy impacts primary care physicians' (PCP) acceptance of duals.

Research Design: We assessed differences in the likelihood that PCPs had dual caseloads of ≥10% or 20% in states with lower versus full dual reimbursement using linear probability models adjusted for physician and area-level traits. Using a triple-difference approach, we examined changes in dual caseloads for PCPs versus a control group of specialists in states with fee bumps versus no change during years postbump versus prebump.

Subjects: PCPs and specialists (cardiologists, orthopedic surgeons, general surgeons) that billed fee-for-service Medicare.

Measures: State dual payment policies and physicians' dual caseloads as a percentage of their Medicare patients.

Results: In 2012, 81% of PCPs had dual caseloads of ≥10% and this was less likely among PCPs in states with lower versus full dual reimbursement (eg, difference=-4.52 percentage points; 95% confidence interval, -6.80 to -2.25). The proportion of PCPs with dual caseloads of ≥10% or 20% decreased significantly between 2012 and 2017 and the fee bump was not consistently associated with increases in dual caseloads.

Conclusions: Pre-ACA, PCPs' participation in the dual program appeared to be lower in states with lower reimbursement for duals. Despite the ACA fee bump, dual caseloads declined over time, raising concerns of worsening access to care.