Spike in Radiologist Accountable Care Organization Participation

Radiologist involvement in Medicare Shared Savings Program (MSSP) accountable care organizations (ACOs) has increased significantly in recent years, showing promise for increased specialist participation in value-based care, according to a recent study published in the Journal of the American College of Radiology.

Using CMS data, researchers found that radiologist participation in MSSP ACOs grew from 10.4 percent to 34.9 percent from 2013 to 2018. These results suggest that overall specialist involvement in MSSP ACOs is on the rise, and the trend may be crucial for ACO cost reduction, the study explains.

“We believe that our work shows that MSSP ACOs are increasingly recruiting radiologists into their plans alongside other specialty care providers, potentially preparing themselves to better assume downside risk in the program while simultaneously improving care and clinical outcomes,” said Stefan Santavicca, MS, the study’s lead investigator and economics research associate at the Georgia Institute of Technology Health Economics and Analytics Lab (HEAL), in a press release.

“Further research on the impact of ACO expansion on imaging utilization and equipment ownership may help radiologists promote greater value as they increasingly participate in MSSP ACOs.”

The MSSP gives providers the tools to form an ACO, thus encouraging the use of alternative payment models (APMs). As of 2021, there are 477 MSSP ACOs in the US, according to CMS’ website. Participants can choose from different participation pathways that fit their needs.

In the past, physician-led ACOs consisted largely of primary care physicians, rather than specialists, the study stated. Researchers attribute the growth in radiologist participation to the 2018 structural changes to MSSP, specifically CMS’ Pathways to Success initiative. However, the study also notes that the Pathways to Success rule “may make radiologists more of a liability to the ACO because of their associated costs without any definite benefit of adding to shared savings.”

“Radiologists participating in MSSP ACOs who are incentivized to help manage imaging, however, may have opportunities to be seen as part of solutions rather than problems,” the study stated.

The study found that between 2013 and 2018, the number of participating radiologists in the Medicare program rose 6.3 percent, from 30,299 to 32,202. At the same time, the number of ACO-affiliated radiologists increased by 245 percent, from 3,508 to 12,103. Meanwhile, ACO-affiliated radiologists participating in Medicare increased by 235.6 percent.  

“During that time, the fraction of large ACOs with participating radiologists averaged 87 [percent], while the fraction of medium and small ACOs with participating radiologists rose from 62.5 [percent] to 66.9 [percent] and from 26.3 [percent] to 51.6 [percent], respectively,” the study revealed.

During the time in question, the number of Medicare-participating and ACO-affiliated radiologists increased in all US states, with the exception of Vermont, Wisconsin, and Idaho. In these states, Medicare participation for radiologists did increase, but MSSP ACO-affiliation stayed the same or decreased.

“Overall, MSSP ACOs with radiologist participation were considerably larger, on average affiliated with 4.8 times as many physicians than those without radiologist participation,” the study asserted.

The higher concentration of radiologist participation at hospital-affiliated MSSP ACOS makes sense, researchers say, largely because bigger hospitals have the necessary funds and infrastructure. Hospital-affiliated ACOs typically have more specialist physicians, meaning that the quality of care and potential for savings is greater, the study states.

“While volume-based reimbursement still dominates the healthcare market, value-based reimbursement is gaining ground,” said Danny Hughes, PhD, one of the study’s authors, professor of economics at the Georgia Institute of Technology, and Director of HEAL, in the press release.

“This study shows that economic incentives of value-based care are reaching beyond the patient-facing specialties such as primary care providers to specialties like radiology to whom patients are not typically attributed.”