Accountable care organizations (ACOs) now stretch across 45 U.S. states and Washington, D.C., according to a white paper from Leavitt Partners. The 221 identified ACOs represent a 38 percent increase compared with those identified just six months ago.

ACO activity in the private sector outnumbers the government sector by a factor of four to one, while the majority of ACOs are found in larger metropolitan regions.

The whitepaper, “Growth and Dispersion of Accountable Care Organizations,” updates the original report published in November 2011.

“The consistent growth in the number and variety of organizations adopting accountable care demonstrates the momentum of the ACO movement,” said report author Andrew Croshaw, a partner and managing director of the healthcare practice at Leavitt Partners.

The report stated that hospital systems sponsor the majority of ACOs, but ACOs backed by physician groups have seen the most recent growth. Growth occurring in large population centers is due to ACOs competing with each other.  

The private sector is embracing new payment and care delivery arrangements. The presence of ACOs doing business among and between private payors and providers outnumbers that of the government sector by a factor of four to one. Non-Medicare ACOs are experimenting with more diverse models than Medicare-backed ACOs.

 Access the full report on the Leavitt Partners website.