Accountable care organizations (ACOs) have been a large part of the transition away from fee-for-service payments, with the number of ACOs rapidly growing over the past decade. However, there has been a plateau in the number of ACOs since 2018, with ACO exits outweighing entrants for the past 2 years.1 From our analysis of Medicare Shared Savings Program data,2 we have found that one key category of ACOs has become less likely to join or remain an ACO: physician group–led ACOs. These lower entrance and survival rates are a problem for the ACO movement given the positive shared savings and quality results that many physician group–led ACOs have been able to achieve.3
In this issue of The American Journal of Accountable Care®, Streat et al examined a cohort of Aledade’s physician-led ACOs to understand their evolution, including the specific care changes made by these ACOs, their specific utilization pattern changes compared with others, and overall quality and cost over time.4 The authors, part of Aledade themselves, used a difference-in-differences approach to compare the ACO cohort with their region, largely drawing on Medicare claims. In short, the analysis found that, compared with their region, the ACO cohort made multiple care changes: They expanded the number of attributed members receiving annual wellness visits, significantly increased the number of patients receiving transitional care visits, and overall provided a greater number of primary care visits. The authors report that these care delivery changes were associated with reductions in emergency department usage, inpatient visits, and skilled nursing facility utilization, especially in comparison with their region. Overall, Streat et al find that all 5 ACOs achieved shared savings by their fifth year, and the cohort’s adjusted costs were 13% lower than those of their region compared with a 2015 baseline.