Accountable care organizations were created as a method to try to get some of the benefits of managed care to the fee-for-service Medicare population. But since beneficiaries don’t in any manner enroll in an ACO and aren’t locked into using its providers, the actual ability to control utilization and spending is pretty limited. Even primary care may be sought outside the ACO and a study in Health Affairs examines whether the extent of out-of-ACO-network use is associated with spending increases. (HA Article) The authors used data from 2012 to 2015 on spending and utilization for beneficiaries attributed to ACOs. With information on the composition of the ACO’s primary care network, the researchers calculated the proportion of primary care obtained within and without that network. They then compared levels of total spending and spending for major categories of care. The median level of out-of-network primary care for an ACO was 8% and the median level of out-of-network specialty care was 82%, suggesting that most ACOs are highly focused on including primary care physicians. Over time, ACOs tended to bring slightly more primary care in-network, but the percent of specialty care stayed the same.
The median level of per beneficiary spending was about $1600 per year, but this was highly skewed, with many beneficiaries having very low spending and a few very high spending. Each percentage point increase in out-of-network primary care was associated with about a $43 annual increase in spending. The increase occurred primarily in outpatient care, skilled nursing facility and emergency room spending. Inpatient spending was unchanged. ACOs with higher levels of out-of-network care tended to see sicker and older patients, those who were dually-eligible and members of a minority group, were more likely to be physician-led and had a larger portion of primary care providers. The latter two characteristics are surprising. While the difference isn’t huge, it does suggest that ACOs can benefit by doing what they can to encourage patients to stay in-network for primary care.