McWilliams and colleagues publish study in JAMA Internal Medicine, find challenges ahead for Accountable Care Organizations.

In “Outpatient Care Patterns and Organizational Accountability in Medicare,” published on April 21 in JAMA Internal Medicine, Drs. Michael McWilliams, Michael Chernew and Bruce Landon examined how fragmented and unstable care patterns in Medicare might undermine efforts to foster accountability for quality and costs of care in the Medicare Accountable Care Organization (ACO) programs.

The study looked at 524,246 patients hypothetically assigned to 145 ACOs in 2010-2011, before the Medicare ACO programs began. McWilliams and colleagues found that among patients assigned to an ACO in 2010, 80.4% were assigned to the same ACO in 2011, and among patient assigned to an ACO in either 2010 or 2011, only 66.0% were consistently assigned to the same ACO in both years. In addition, they found that much specialty care received by patients assigned to an ACO was provided by specialists outside of the ACO’s network of physicians; even among more specialty-oriented ACOs, over 50% of outpatient specialty care “leaked” outside of ACOs.  Finally, the authors found that less than 40% of outpatient care provided by ACOs was devoted to patients assigned to them.

These findings suggest that incentives for ACOs to make patient-specific investments may be diminished by instability in the population for which they are held accountable.  Similarly, incentives for ACOs to implement important systemic changes in care delivery may be weak because much of the care they provide may continue to be reimbursed on a fee-for-service basis.  The substantial amount of specialty care leakage also suggests that ACOs may have limited influence over key portions of patients’ care as they attempt to control costs. Overall, the study reveals significant challenges ahead in achieving organizational accountability in Medicare. Continued monitoring of these care patterns may help to determine the need for enhancing ACOs’ incentives and their capacity to improve care efficiency.

Paul Ginsburg, Professor of the Practice of Health Policy and Management at USC Price, wrote in an accompanying editorial, “The results of the study by McWilliams and colleagues confirm the seriousness of failing to link Medicare beneficiaries with ACOs.” Ginsburg reiterates the importance of patients remaining with the same ACO to ensure efficient coordinated care.

Since publication, Drs. McWilliams, Chernew and Landon’s study has been featured in a variety of media outlets, including The Washington Post and Modern Healthcare.

To read the article in full, please visit the JAMA website.