Sources of Variation in Merit-Based Incentive Payment System Quality Performance Among Surgeons

BACKGROUND: The Merit-based Incentive Payment System (MIPS) determines Medicare Part B reimbursement adjustments, yet the extent to which surgical quality performance and reporting reflect physician specialty, practice characteristics, and patient populations remains unclear. We examined variation in MIPS process and outcome measure performance and reporting among surgeons. STUDY DESIGN: This retrospective cross-sectional study analyzed nationwide public-use MIPS data from surgeons in 10 specialties reporting as individuals in 2022 or 2023. Outcome and process measure performance and reporting patterns were evaluated using regression models assuming beta-distributed responses to assess associations with physician practice and Medicare beneficiary characteristics. RESULTS: Overall, 40.2% of reported quality measures fell outside of the reporting physician's specialty-specific measure set. Outcome measure reporting frequencies varied by specialty and beneficiary characteristics. In multivariable analyses, ophthalmologists outperformed all other specialties on outcome measures in 2022 (all p<0.001) and 2023 (all p≤0.01), and on process measures in both years (all p≤0.04). Greater numbers of unique Medicare beneficiaries were positively associated with both outcome and process measure performance in 2022 and 2023 (all p<0.001). CONCLUSIONS: MIPS quality measure performance and reporting varied by surgical specialty, practice characteristics, and Medicare beneficiary coverage. The substantial proportion of measures reported outside specialty-specific sets raises questions about the clinical relevance of current quality reporting. These findings support evaluating specialty-specific measure alignment and the balance between process and outcome measures to better reflect surgical practice.