CMS names 5,556 specialists who must join its new payment model Jan. 1

CMS has named the 5,556 specialists who must take part in its Ambulatory Specialty Model when it launches Jan. 1, 2027, putting a share of their Medicare Part B payments on the line based on how they manage patients with heart failure or low back pain.

That leaves practices little runway. In a Sept. 14 interview with Physicians Practice, a day before CMS posted the final list, Anders Gilberg, senior vice president of government affairs at MGMA, said members were not ready for the launch. "The bottom line is they're not ready because they don't know," Gilberg said. "We don't know which physicians are in or out at this point."

The final roster for the 2027 performance year, which CMS announced this week on its Ambulatory Specialty Model page, is about 16 percent smaller than the preliminary list released in February. That list named 6,637 clinicians, according to an analysis by Value-Based Care Advisors. A Physicians Practice review of the final ASM participants dataset found both cohorts shrank. The heart failure group fell from 2,610 clinicians to 2,215, and the low back pain group dropped from 4,027 to 3,341.

Who is on the list

Cardiologists make up the entire heart failure cohort. The low back pain cohort includes 826 physical medicine and rehabilitation physicians, 760 orthopedic surgeons, 627 pain management physicians, 487 anesthesiologists, 395 interventional pain management physicians and 246 neurosurgeons.

Participants work at 2,308 organizations in 232 metro areas across 46 states. Texas accounts for 960 participants, about 17 percent of the total, followed by California with 586, Florida with 481, Georgia with 303 and New Jersey with 263. The Houston and Dallas metro areas lead all regions with 307 and 271 participants, respectively, followed by the Lakewood-New Brunswick, New Jersey, area with 241 and metro Atlanta with 208.

Inova Health Care Services has more participants than any other organization, with 37. HealthTexas Provider Network follows with 35, then OrthoLoneStar and Lehigh Valley Physician Group with 31 each and St. Luke's Physician Group with 30.

A heavy small-practice footprint

CMS flags 2,101 participants, or 38 percent, as working in small practices. That share climbs to 42 percent in the low back pain cohort and 65 percent among interventional pain management physicians, compared with 31 percent in the heart failure cohort.

Geography matters, too. Most participants in Florida (61 percent), California (55 percent) and Texas (51 percent) work in small practices, compared with 9 percent in Washington and 12 percent in Ohio and Indiana.

What is at stake

The model scores each participant on quality, cost, improvement activities and interoperability, using a structure built on MIPS Value Pathways. Based on performance relative to peers, participants receive a positive, neutral or negative adjustment on future Part B claims for covered professional services. Those adjustments range from negative 9 percent to positive 9 percent in the first two performance years and widen to 12 percent in either direction by the final year, according to CMS.

The money moves two years after the work. The model's five performance years run through 2031, while its payment years run from 2029 through 2033, according to the CMS fact sheet. That means care delivered in 2027 drives 2029 payments.

Because the adjustment applies across a participant's Part B professional services rather than just back pain or heart failure visits, a physician with relatively few targeted patients still has broad revenue exposure, a point the American College of Surgeons raised in opposing the model. Participation is mandatory, and there is no opt-out.

To be selected, specialists must have been attributed at least 20 heart failure or low back pain episodes a year and practice in one of the model's mandatory geographic areas, which cover roughly one-quarter of metro areas nationwide, CMS said.

What practices should do now

Administrators should search the dataset by NPI for every physician in the group, including those who were not on February's list. The preliminary list relied on 2024 claims, while the final list drew on 2025 data, according to a summary from the law firm Benesch. The file also lists 23 NPIs more than once, in some cases under different metro areas, so practices should confirm how each physician is recorded.

Gilberg said the notification process itself worries MGMA. CMS' ASM onboarding checklist tells clinicians who are on the list but did not receive a notification email to register for the ASM Participant Portal using their own NPI, then add colleagues as organizational contacts. MGMA would prefer a setup that lets a group practice administrator see every physician in the practice at once, he said.

"Having individual physicians setting up accounts and then having the administrator as a secondary to that account is just going to cause a lot of administrative hassle," Gilberg said. He credited CMS for its outreach to MGMA, noting the agency has "some talented people working on it."

CMS is hosting a September office hour on the portal and onboarding, with a live Q&A. Practices on the list should also review how their physicians perform on the heart failure and low back pain episode-based cost measures and start formalizing collaborative care arrangements with the primary care physicians who refer to them.

The rules could still shift before launch. CMS proposed changes to the model in the CY 2027 Physician Fee Schedule proposed rule, and the comment period closed Sept. 14. Gilberg said MGMA expects the final rule on or about Nov. 1, which "gives a short period of time for practices to prepare" before the first performance year opens Jan. 1.