As accountable care organizations (ACO) evaluate revised CMS program options for 2020, a new study has determined groups are most likely to stay in the Medicare Shared Savings Program (MSSP) if they achieved bonuses, even if was just once.

The analysis published in Health Affairs, found the risk of an ACO leaving the Medicare program is cut by more than three-quarters if they receive shared savings for at least one performance year. Overall, 30% of the 624 ACOs that participated at some point in the first five years of the program left.

In 2017, the most recent year data are available, about 60% of Medicare ACOs generated a total of $1.1 billion in savings for the CMS.

The study also found that ACOs are most likely to exit the program in their third year. The rate of program exit for third-year ACOs was 20.7%. By comparison, the program exit rate for first-year ACOs was 4%, 9.5% for ACOs in their second year, 10.6% for fourth-year ACOs and 11.2% for ACOs in their fifth year.

The changes to the MSSP program in 2020 – known as Pathways to Success - will require ACOs to take on downside risk after one to three years depending on their revenue. For most ACOs that means they will have to take on downside risk after two years in the program.

Research finds that physician-led ACOs are more likely to drop out of the program, but the fact that the CMS program accounts for an ACO's revenue, most physician-led ACOs likely won't have to take on downside risk until after three years in the program.