Are Quality Scores in the Centers for Medicaid and Medicare Services Merit-based Incentive Payment System Associated With Outcomes After Outpatient Orthopaedic Surgery?
Authors: Schloemann Derek T. , Wilbur Danielle M. , Rubery Paul T. , Thirukumaran Caroline P. 
Published: March 2024

Background
The Medicare Merit-based Incentive Payment System (MIPS) ties reimbursement incentives to clinician performance to improve healthcare quality. It is unclear whether the MIPS quality score can accurately distinguish between high-performing and low-performing clinicians.

Questions/purposes
(1) What were the rates of unplanned hospital visits (emergency department visits, observation stays, or unplanned admissions) within 7, 30, and 90 days of outpatient orthopaedic surgery among Medicare beneficiaries? (2) Was there any association of MIPS quality scores with the risk of an unplanned hospital visit (emergency department visits, observation stays, or unplanned admissions)?

Methods
Between January 2018 and December 2019, a total of 605,946 outpatient orthopaedic surgeries were performed in New York State according to the New York Statewide Planning and Research Cooperative System database. Of those, 56,772 patients were identified as Medicare beneficiaries and were therefore potentially eligible. A further 34% (19,037) were excluded because of missing surgeon identifier, age younger than 65 years, residency outside New York State, emergency department visit on the same day as outpatient surgery, observation stay on the same claim as outpatient surgery, and concomitant high-risk or eye procedures, leaving 37,735 patients for analysis. The database does not include a list of all state residents and thus does not allow for censoring of patients who move out of state. We chose this dataset because it includes nearly all hospitals and ambulatory surgery centers in a large geographic area (New York State) and hence is not limited by sampling bias. We included 37,735 outpatient orthopaedic surgical encounters among Medicare beneficiaries in New York State from 2018 to 2019. For the 37,735 outpatient orthopaedic surgical procedures included in our study, the mean ± standard deviation age of patients was 73 ± 7 years, 84% (31,550) were White, and 59% (22,071) were women. Our key independent variable was the MIPS quality score percentile (0 to 19th, 20th to 39th, 40th to 59th, or 60th to 100th) for orthopaedic surgeons. Clinicians in the MIPS program may receive a bonus or penalty based on the overall MIPS score, which ranges from 0 to 100 and is a weighted score based on four subscores: quality, promoting interoperability, improvement activities, and cost. The MIPS quality score, which attempts to reward clinicians providing superior quality of care, accounted for 50% and 45% of the overall MIPS score in 2018 and 2019, respectively. Our main outcome measures were 7-day, 30-day, and 90-day unplanned hospital visits after outpatient orthopaedic surgery. To determine the association between MIPS quality scores and unplanned hospital visits, we estimated multivariable hierarchical logistic regression models controlling for MIPS quality scores; patient-level (age, race and ethnicity, gender, and comorbidities), facility-level (such as bed size and teaching status), surgery and surgeon-level (such as surgical procedure and surgeon volume) covariates; and facility-level random effects. We then used these models to estimate the adjusted rates of unplanned hospital visits across MIPS quality score percentiles after adjusting for covariates in the multivariable models.

Results
In total, 2% (606 of 37,735), 2% (783 of 37,735), and 3% (1013 of 37,735) of encounters had an unplanned hospital visit within 7, 30, or 90 days of outpatient orthopaedic surgery, respectively. Most hospital visits within 7 days (95% [576 of 606]), 30 days (94% [733 of 783]), or 90 days (91% [924 of 1013]) were because of emergency department visits. We found very small differences in unplanned hospital visits by MIPS quality scores, with the 20th to 39th percentile of MIPS quality scores having 0.71% points (95% CI -1.19% to -0.22%; p = 0.004), 0.68% points (95% CI -1.26% to -0.11%; p = 0.02), and 0.75% points (95% CI -1.42% to -0.08%; p = 0.03) lower than the 0 to 19th percentile at 7, 30, and 90 days, respectively. There was no difference in adjusted rates of unplanned hospital visits between patients undergoing surgery with a surgeon in the 0 to 19th, 40th to 59th, or 60th to 100th percentiles at 7, 30, or 90 days.

Conclusion
We found that the rates of unplanned hospital visits after outpatient orthopaedic surgery among Medicare beneficiaries were low and primarily driven by emergency department visits. We additionally found only a small association between MIPS quality scores for individual physicians and the risk of an unplanned hospital visit after outpatient orthopaedic surgery. These findings suggest that policies aimed at reducing postoperative emergency department visits may be the best target to reduce overall postoperative unplanned hospital visits and that the MIPS program should be eliminated or modified to more strongly link reimbursement to risk-adjusted patient outcomes, thereby better aligning incentives among patients, surgeons, and the Centers for Medicare ad Medicaid Services. Future work could seek to evaluate the association between MIPS scores and other surgical outcomes and evaluate whether annual changes in MIPS score weighting are independently associated with clinician performance in the MIPS and regarding clinical outcomes.

Level of Evidence
Level III, therapeutic study.