Use of Preventive Care Services and Hospitalization Among Medicare Beneficiaries in Accountable Care Organizations That Exited the Shared Savings Program

IMPORTANCE: Thirty percent of Medicare accountable care organizations (ACOs) in the Shared Savings Program (SSP) have exited within 5 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 delivered to Medicare beneficiaries. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study was conducted between 2019 and 2020 using national Medicare claims data from a 20% random sample of beneficiaries. A total of 1 713 237 beneficiaries were aligned with an SSP ACO at some point between 2012 and 2016. Distinction was made between those for whom the ACO to which they were aligned exited the SSP and those whose ACO stayed in the program. By comparing exiting ACOs with those that stayed in the SSP, changes in the quality of care that a beneficiary received before and after the aligned ACO exited the SSP were evaluated. Whether findings associated with exit varied with respect to the number of years after exit was also examined. EXPOSURES: Exiting the SSP and the number of years after exit. MAIN OUTCOMES AND MEASURES: Receipt of annual preventive care services and hospital utilization. RESULTS: Among the cohort of 1 713 237 beneficiaries (mean [SD] age at enrollment, 75.20 [7.96] years), 998 511 (58.3%) were female, 126 123 (7.4%) were Black, and 1 482 823 (86.6%) were White. Exiting the SSP was associated with statistically significantly lower rates of annual glycated hemoglobin A(1c) testing (odds ratio [OR], 0.74; 95% CI, 0.68-0.81), low-density lipoprotein cholesterol testing (OR, 0.86; 95% CI, 0.76-0.97), and all diabetes complication screening (OR, 0.90; 95% CI, 0.81-0.97) for beneficiaries with diabetes. The exit was not associated with rates of hospital utilization in terms of emergency department visits and 30-day readmission after SSP exit. The associations with exit depended on the length of time since contracts ended. For example, the baseline rate of annual glycated hemoglobin A(1c) testing was 89.8% (95% CI, 89.5%-90.1%) but fell to 86.9% (95% CI, 85.9%-88.0%) and 86.8% (95% CI, 85.0%-88.5%) in years 1 and 2 after exit, respectively, but then rose to 91.9% (95% CI, 85.3%-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 are timely given recent SSP changes that could accelerate program exit.