More than 359,000 clinicians have agreed to participate in four alternative payment models in 2017, the Centers for Medicare & Medicaid Services announced yesterday. Accountable care organizations in the Medicare Shared Savings Program grew by a net 47 to 480, including 26 Track 3 ACOs waived from the requirement for a three-day inpatient stay prior to Medicare-covered services at a skilled nursing facility, CMS said. Track 2 and 3 ACOs in the MSSP qualify this year as advanced APMs under the Medicare Quality Payment Program. The Next Generation ACO model, also an advanced APM this year, added 28 ACOs in 2017 for a total of 45, CMS said. The Comprehensive End Stage Renal Disease Care (CEC) Model, an ACO model for dialysis facilities, nephrologists and other providers, added 24 ACOs in 2017 for a total of 37. Certain CEC tracks also qualify as advanced APMs. In addition to these Medicare ACO models, about 13,000 primary care clinicians in 14 regions will participate in the new Comprehensive Primary Care Plus model, a multi-payer medical home model, CMS said. The agency also released a request for applications from ACOs interested in joining the Next Generation ACO model in 2018.