Changes in spending, utilization, and quality of care among Medicare accountable care organizations during the COVID-19 pandemic.

The COVID pandemic disrupted health care spending and utilization, and the Medicare Shared Savings Program (MSSP), Medicare's largest value-based payment model with 11.2 million assigned beneficiaries, was no exception. Despite COVID, the 513 accountable care organizations (ACO) in MSSP returned a program record $1.9 billion in net savings to Medicare in 2020. To understand the extent of COVID's impact on MSSP cost and quality, we describe how ACO spending changed in 2020 and further analyze changes in measured quality and utilization. We found that non-COVID per capita spending in MSSP fell by 8.3 percent from $11,496 to $10,537 (95% confidence interval(CI),-1,223.8 to-695.4, p<0.001), driven by 14.6% and 7.5% reductions in per capita acute inpatient and outpatient spending, respectively. Utilization fell across inpatient, emergency, and outpatient settings. On quality metrics, preventive screening rates remained stable or improved, while control of diabetes and blood pressure worsened. Large reductions in non-COVID utilization helped ACOs succeed financially in 2020, but worsening chronic disease measures are concerning. The appropriateness of the benchmark methodology and exclusion of COVID-related spending, especially as the virus approaches endemicity, should be revisited to ensure bonus payments reflect advances in care delivery and health outcomes rather than COVID-related shifts in spending and utilization patterns.