RESUMO
The Next Generation Accountable Care Organization (NGACO) model (active during 2016-21) tested the effects of high financial risk, payment mechanisms, and flexible care delivery on health care spending and value for fee-for-service Medicare beneficiaries. We used quasi-experimental methods to examine the model's effects on Medicare Parts A and B spending. Sixty-two ACOs with more than 4.2 million beneficiaries and more than 91,000 practitioners participated in the model. The model was associated with a $270 per beneficiary per year, or approximately $1.7 billion, decline in Medicare spending. After shared savings payments to ACOs were included, the model increased net Medicare spending by $56 per beneficiary per year, or $96.7 million. Annual declines in spending for the model grew over time, reflecting exit by poorer-performing NGACOs, improvement among the remaining NGACOs, and the COVID-19 pandemic. Larger declines in spending occurred among physician practice ACOs and ACOs that elected population-based payments and risk caps greater than 5 percent.