How Does CMS' Merit-based Incentive Payment System Penalize or Reward Orthopaedic Surgeons Caring for Socially At-risk Patients?

Background: The largest value-based payment system in the United States is the Merit-based Incentive Payment System (MIPS), implemented by the Centers for Medicare & Medicaid Services (CMS). MIPS was designed to adjust physician reimbursement based on performance across several categories. However, concerns arose that MIPS may inadvertently penalize physicians caring for patients of high social risk. To address this concern, CMS introduced the Complex Patient Bonus (CPB), which provides a performance bonus for serving a greater proportion of dually eligible, or socially at-risk (as defined by CMS), patients. In orthopaedic surgery, there is a paucity of evidence assessing MIPS performance (such as scores and payment adjustments), the association between patient social risk and MIPS scores, and the relationship of the newly implemented CPB with performance scores.

Questions/purposes: In this study, we asked: (1) How do orthopaedic surgeons fare in MIPS based on positive, negative, and bonus payment adjustments? (2) Do orthopaedic surgeons caring for more socially at-risk patients receive worse performance scores and payment adjustments than orthopaedic surgeons who treat fewer socially at-risk patients? (3) To what extent is the CPB associated with differences in MIPS scores and payment adjustments for orthopaedic surgeons caring for a greater proportion of socially at-risk patients?

Methods: Orthopaedic surgeons participating in MIPS in 2021 were identified using publicly available, nationally representative, standardized CMS data sets, consistent with prior studies assessing clinician performance under MIPS. In keeping with prior studies and consistent with how CMS defines social risk for the purpose of adjusting MIPS performance and payments using the CPB, dual eligibility for Medicare and Medicaid was used as a proxy for social risk. Surgeons were stratified into quintiles based on the proportion of patients dually eligible for Medicare and Medicaid. To answer the first question about how orthopaedic surgeons, in aggregate, perform in MIPS, CMS MIPS outcome data were used to quantify the proportion of surgeons who received a positive or negative payment adjustment, an exceptional performance bonus, and a maximum payment penalty. To address the second question regarding the association between caring for socially at-risk patients and MIPS performance, MIPS scores and payment adjustments were compared between surgeons in the highest and lowest quintiles of patient social risk, as determined by the proportion of dually eligible patients in each surgeon's practice per CMS definition. To evaluate the extent to which the CPB is associated with differences in MIPS performance, multivariable regression was used to assess whether the proportion of socially at-risk patients in a surgeon's practice was associated with differences in MIPS scores, payment adjustments, and exceptional performance bonuses, with and without the CPB.

Results: Regarding how orthopaedic surgeons performed in MIPS, 97% (9415 of 9707) of orthopaedic surgeons in the study received a positive payment adjustment, and 0.5% (50 of 9707) received the maximum penalty. When comparing surgeons caring for more socially at-risk patients with those caring for fewer (mean ± SD proportion of dual eligible patients 31% ± 11% versus 2% ± 2%; p < 0.001), surgeons in the highest social risk quintile achieved higher MIPS scores (with CPB 94 versus 91, p < 0.001; without CPB 90 versus 88, p = 0.001). However, no difference in payment adjustments was observed between surgeons caring for the highest and lowest proportion of socially at-risk patients (lowest quintile, any positive MIPS score adjustment 96% [1872 of 1943] versus highest quintile, any positive MIPS score adjustment 96% [1870 of 1942]; p = 0.93). In examining the role of the CPB, caring for a higher proportion of socially at-risk patients was associated with a higher MIPS score with the CPB (β 1.9 [95% confidence interval (CI) 0.51 to 3.20]; p = 0.007), but not without the CPB (β 0.6 [95% CI -0.79 to 2.02]; p = 0.39). No association was found between the proportion of socially at-risk patients cared for and receipt of an exceptional performance bonus (odds ratio [OR] 1.3 [95% CI 0.95 to 1.72]; p = 0.10) or positive payment adjustment (OR: 0.8 [95% CI 0.46 to 1.34]; p = 0.37).

Conclusion: Our findings highlight potential disconnect between MIPS performance and financial implications, particularly for surgeons treating more socially at-risk patients. The lack of differentiation in performance outcomes, evidenced by nearly all participating surgeons receiving a positive adjustment in a budget-neutral program, raises concerns about how MIPS measures and rewards performance. As new value-based payment models continue to be introduced, including those with greater downside or variation in payment adjustments, ensuring appropriate risk-adjustment is crucial to their success and achieving buy-in from practicing orthopaedic surgeons. For orthopaedic surgeons, these findings may contextualize their MIPS performance, clarify the limited role that payment adjustments play in recognizing surgeons who care for more complex or socially at-risk patients, and inform how they engage with institutional quality initiatives or advocate for more meaningful, clinically oriented performance measures. Future studies should evaluate whether a narrower set of episode-based, patient-centric metrics may better reflect the quality of surgical care provided and support outcome-focused value-based payment models.

Level of evidence: Level III, therapeutic study.