Importance: Thirty percent of Medicare accountable care organizations (ACOs) in the Shared Savings Program (SSP) have exited within five years of joining. Absent the potential for shared savings, exiting ACOs may choose to divest from costly resources needed to support population health, worsening clinical quality for beneficiaries aligned to these organizations.
Objective: To examine the associations of SSP exit with clinical quality.
Design setting and participants: Between 2019 and 2020 we conducted a retrospective cohort study with national Medicare claims from a 20% random sample of beneficiaries. We identified 1,713,237 beneficiaries aligned with an SSP ACO at some point between 2012 and 2016. We distinguished between those for whom the ACO to which they were aligned exited the SSP and those whose ACO stayed in the program. Comparing exiting ACOs with those who stayed in the SSP, we evaluated changes in the quality of care that a beneficiary received before and after the aligned ACO exited the SSP. We also examined whether findings associated with exit varied with respect to the number of years after exit.
Exposures: SSP exit and the number of years after exit.
Main outcomes and measures: Annual preventive care services receipt and hospital utilization.
Results: The cohort of 1,713,237 individuals (mean [standard deviation] age at enrollment: 75.20 [7.96] years) included 998,511 (58.3%) female, 126,123 (7.4%) Black, and 1,482,823 white (86.6%) beneficiaries. SSP exit was associated with significantly lower rates of annual glycated hemoglobin testing (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.68 to 0.81), low-density lipoprotein cholesterol testing (OR, 0.86; 95% CI, 0.76 to 0.97), and all diabetes complication screening (OR, 0.90; 95% CI, 0.81 to 0.97), for beneficiaries with diabetes. The exit was not related to rates of hospital utilization, in terms of emergency department utilization and 30-day readmission after SSP exit. The associations with exit depended on the length of time since contracts end. For example, the baseline rate of annual glycated hemoglobin testing was 89.8% (95% CI, 89.5% to 90.1%) but fell to 86.9% (95% CI, 85.9% to 88.0%) and 86.8% (95% CI, 85.0% to 88.5%) in years 1 and 2 after exit, respectively, but it then rose to 91.9% (95% CI, 85.3% to 98.5%) in year 3.
Conclusions and relevance: In this cohort study of Medicare beneficiaries, SSP exit was associated with modest declines in clinical quality. These findings were timely given recent SSP changes that could accelerate program exit.