Skip to content Skip to navigation

A Study of ACO-Based Care Management Shows that Results Are Highly Replicable

May 19, 2017
| Reprints
A study of the early care management work undertaken at Mass General holds positive implications going forward

I read with great interest an article published in the May issue of Health Affairs, based on a study of results coming out of Pioneer ACO Program accountable care organizations. The article, written by a large team of researchers—John Hsu, Mary  Price, Christine Vogeli, Richard Brand, Michael E. Chernew, Sreekanth K. Chaguturu, Eric Weil, and Timothy G. Ferris—was entitled “Bending The Spending Curve By Altering Care Delivery Patterns: The Role Of Care Management Within A Pioneer ACO.”

In it, Hsu and his fellow researchers described how they examined care management practices implemented at Massachusetts General Hospital in Boston, and what they found. As they wrote in their abstract, “Accountable care organizations (ACOs) appear to lower medical spending, but there is little information on how they do so. We examined the impact of patient participation in a Pioneer ACO and its care management program on rates of emergency department (ED) visits and hospitalizations and on Medicare spending,” the authors wrote. “We used data for the period 2009–14, exploiting naturally staggered program entry to create concurrent controls to help isolate the program effects. The care management program (the ACO’s primary intervention) targeted beneficiaries with elevated but modifiable risks for future spending. ACO participation had a modest effect on spending, in line with previous estimates. Participation in the care management program was associated with substantial reductions in rates for hospitalizations and both all and nonemergency ED visits, as well as Medicare spending, when compared to preparticipation levels and to rates and spending for a concurrent sample of beneficiaries who were eligible for but had not yet started the program. Rates of ED visits and hospitalizations were reduced by 6 percent and 8 percent, respectively, and Medicare spending was reduced by 6 percent. Targeting beneficiaries with modifiable high risks and shifting care away from the ED represent viable mechanisms for altering spending within ACOs.”

By way of background, Hsu and his coauthors wrote, “Before the start of the Pioneer ACO program, one of the main hospitals within the Partners HealthCare System, Massachusetts General Hospital, had participated in the Medicare Care Management for High Cost Beneficiaries Demonstration and had developed an intensive care management program. The study ACO extended this program throughout the Partners HealthCare System with no changes to the basic structure of the program, except for centralizing operations. The care management program represented the ACO’s primary strategy for achieving its contractual cost and quality goals under the Pioneer ACO program,” the coauthors noted. “The ACO employed no other contemporaneous, systematic programs. Specifically, the care management program identified beneficiaries who first appeared likely to be at high risk for future spending and then selected the subset of this group whose costs appeared to be modifiable, using information from each beneficiary’s primary care physician. These beneficiaries with elevated but potentially modifiable risks for future spending were eligible for the care management program.”

The study’s authors hypothesized that the rates of ED visits and inpatient admissions would decline over time with greater exposure to the care management program, and also that spending would increase initially as unmet needs were addressed but then decline in response to the program’s effects.

Importantly, the researchers found the following:

>  Overall participation in the ACO was associated with lower ED visit rates, both for all ED visits (91 percent of the rates of nonparticipants) and for nonemergency visits (86 percent). As beneficiaries’ length of participation in the ACO increased, the rate of ED visits—both overall and nonemergency visits—declined in stepwise fashion.

>  Participants’ rates for hospitalizations were 92 percent of the rates for nonparticipants. Hospitalization rates increased initially after program entry and then declined in a stepwise fashion with increasing length of exposure. The increase was not significant, but the subsequent declines were.

>  Overall participation in the ACO was associated with a reduction in Medicare spending of $14 per participant per month (Exhibit 4), a decline of 2 percent. This association was not significantly different from no change, but the magnitude of the decline was comparable to estimates in previous studies. The associations between length of ACO participation and reduced Medicare spending were significant.

> Overall participation in the care management program was associated with a reduction in Medicare spending of $101 per participant per month, a decline of 6 percent. The spending reductions increased with longer program exposure, in a stepwise fashion. All associations were significant except that between spending and program participation in the first six months.