Accountable care organisations are being touted as an innovation that may slow the rate of increase in costs and improve quality of care in the US. They take many forms, but in essence are groups of providers that deliver care to a defined population. These providers are held accountable for achieving quality outcomes within a given budget.
There are currently around 600 ACOs in the US serving an estimated 20 million people. Emerging evidence on their performance is mixed, both in relation to cost savings and quality improvements. Promising initiatives such as those seen under the alternative quality contract in Massachusetts co-exist with examples of ACOs not delivering benefits and in some cases deciding to drop out of Medicare’s pioneer programme.