Abstract
OBJECTIVES: To assess whether physicians participating in the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) exhibit different billing behaviors and practice patterns compared to non-participating physicians after MACRA implementation. STUDY SETTING AND DESIGN: A quasi-experimental staggered difference-in-difference design was used to compare pre-and post-MACRA changes among participants and non-participants from 2013 to 2021. Primary outcomes included annual submitted charges, annual Medicare payments, and charge-to-payment ratios. Secondary outcomes were average charges and payments per beneficiary, total services, and the number of beneficiaries served. DATA SOURCES AND ANALYTIC SAMPLE: The study analyzed secondary data from Centers for Medicare & Medicaid Services (CMS) Medicare Fee-For-Service Provider Utilization and Payment Data (2013-2021), providing outcome measures and control variables; Quality Payment Program (QPP) Experience Reports (2017-2021), the National Plan and Provider Enumeration System, and Medicare Geographic Variation Public Use File. The analytic sample included 4,924,118 physician-year observations (749,129 unique physicians), with 50.2% participating in MACRA. PRINCIPAL FINDINGS: MACRA participation was associated with significant annual increases of $36,677 (95% CI: 28,918, 44,436) in total submitted charges and $9164 (95% CI: 7288, 11,041) in total Medicare payments compared to non-participation. However, these increases appeared primarily driven by a substantial increase in the total number of Medicare beneficiaries served per physician (29.77 beneficiaries; 95% CI: 20.75, 32.79) rather than by increases in spending per beneficiary, which were modest (average payment increase per beneficiary of $2.10; 95% CI: 0.22, 3.97). The charge-to-payment ratio decreased by 0.04 percentage points (95% CI: -0.08, -0.00) among MACRA participants, suggesting potential improvements in billing efficiency. CONCLUSIONS: MACRA participation is associated with increased billing and payment among Medicare Part B physicians, primarily driven by physicians treating a greater number of Medicare beneficiaries. However, modest changes in per-beneficiary spending suggest limited changes in care intensity. Further research is needed to explore factors influencing patient volumes and payer mix under MACRA.