From widening commercial price gaps and declining Medicare surgeon pay, five studies are raising questions about the financial and structural pressures facing ASCs.
The studies quantify shrinking surgeon reimbursement, consolidation-linked price increases, hospital site-of-care advantages and socioeconomic disparities in ASC expansion.
Here are five studies ASC leaders are watching:
1. Commercial payers still pay far more at HOPDs
Commercial insurers paid an average of $1,489 more for common procedures at hospital outpatient departments than at ASCs in 2024, a 78% mark-up, according to a study published in Health Affairs. Researchers analyzed negotiated-rate data from UnitedHealthcare, Cigna and BlueCross BlueShield for 13 high-volume outpatient procedures that together account for nearly two-thirds of outpatient surgical cases.
Medicare also paid more when those procedures were performed in HOPDs, but the difference was smaller in dollars: $633 more per case, a 97% mark-up. Among the commercial payers, Cigna had the narrowest gap, at $327. The study noted that Cigna contracted with just 14% of HOPDs in applicable markets, compared with an average of 76% for UnitedHealthcare and BlueCross BlueShield. If those two payers paid Cigna’s average HOPD rates for the 13 procedures, they would save an estimated $1.4 billion annually.
2. Surgeon payment for ASC arthroplasty is shrinking, even after inflation
For hip and knee arthroplasty procedures performed in ASCs, Medicare professional fees for surgeons declined from 2018 to 2024, even after adjusting for inflation, according to a July 2025 report on Science Direct.
Over that period, unicompartmental knee arthroplasty professional fees fell from about $1,487 to around $1,148. Total knee arthroplasty surgeon fees dropped from roughly $1,739 to about $1,279, and total hip arthroplasty professional fees declined from about $1,741 to around $1,281. Facility payments also fell, though less sharply. UKA facility fees dipped from roughly $9,008 to $8,906, while TKA facility payments declined from about $10,204 to $9,049.
3. ASC growth is skewing toward wealthier counties
ASCs are more likely to open in counties with stronger healthcare infrastructure and higher socioeconomic advantage, according to a study published in Health Affairs Scholar. Counties in the least-deprived (best-off) area-deprivation index quartile had an adjusted ASC opening rate of 31.9%, compared with 19.9% in the most-deprived quartile. Additionally, the odds of an opening fell steadily as deprivation increased.
The strongest predictor of a new opening was the presence of an existing ASC. Adjusted opening rates were 44.7% in counties that already had an ASC, compared with 13.8% in counties without one.
4. Vertical integration appears to shift cases to HOPDs, raising costs for Medicare and patients
The vertical integration of physician groups and health systems is associated with a shift in procedures toward hospital outpatient departments over ASCs, driving up Medicare spending and patient out-of-pocket costs, according to a 2024 study published in Science Direct,
Following vertical integration, the study found a 5-percentage-point increase in the use of HOPDs instead of ASCs for arthroscopy, and a 6.8-percentage-point increase for colonoscopies. The authors also estimated that vertical integration increased the probability of choosing an HOPD over an ASC by 3.1 percentage points for arthroscopy and 8.1 percentage points for colonoscopies. In a scenario where relationships move from “status quo to fully integrated” for all physicians, the study estimated a $315.4 million increase in Medicare spending and a $63.1 million increase in patients’ out-of-pocket costs for those two procedures.
5. Optum’s acquisition of ASCs is tied to higher prices for rival insurers
The acquisition of ASCs by UnitedHealth Group’s Optum, parent company of ASC chain SCA Health, was associated with an 11% increase in prices charged to competing commercial insurers, according to a February study published in Health Affairs. Across seven high-volume services, the average increase was $239 per procedure.
The price increases emerged about two quarters after Optum acquired SCA Health (then Surgical Care Affiliates) in early 2017 and persisted through the remainder of the study period, suggesting a sustained effect rather than a short-term adjustment. The study attributed much of the increase to higher professional fees for Optum-employed physicians: Professional fees rose by $134 per procedure for Optum physicians, while fees for independent physicians showed no statistically significant change.
In highly vertically integrated markets, prices rose by more than $370 per procedure. Despite concerns that insurer ownership could steer patients to ASCs, the authors found no significant post-acquisition shift in referral patterns. Instead, they found evidence consistent with “strategic selection:” Practices acquired by Optum already referred a higher share of patients to ASCs before acquisition (81.3% versus 69.8% at non-Optum practices) even after accounting for patient characteristics.
SCA Health sought to downplay the study results, citing the study’s reliance on what it called “narrow datasets and limited markets,” which did “not reflect the accessible, affordable care ambulatory surgery centers provide.”
“SCA Health delivers high‑quality, affordable outpatient surgical care, giving patients access to convenient care and treatment options closer to home,” said SCA.
