Achieving Population Health in Accountable Care Organizations

Karen Hacker, MD, MPH; Deborah Klein Walker, EdD


Am J Public Health. 2013;103(7):1163-1167. 

In This Article

Abstract and Introduction


Although "population health" is one of the Institute for Healthcare Improvement's Triple Aim goals, its relationship to accountable care organizations (ACOs) remains ill-defined and lacks clarity as to how the clinical delivery system intersects with the public health system.
Although defining population health as "panel"management seems to be the default definition, we called for a broader "community health" definition that could improve relationships between clinical delivery and public health systems and health outcomes for communities.
We discussed this broader definition and offered recommendations for linking ACOs with the public health system toward improving health for patients and their communities.


With the passage of the Affordable Care Act (ACA),[1] the United States has turned its attention to improving the quality of health care while simultaneously decreasing cost. As we move toward alternative and global payment arrangements, the need to understand the epidemiology of the patient population will become imperative. Keeping this population healthy will require enhancing our capacity to assess, monitor, and prioritize lifestyle risk factors that unduly impact individual patient health outcomes. This is especially true, given that only 10% of health outcomes are a result of the medical care system, whereas from 50% to 60% are because of health behaviors.[2,3] To change health behaviors, it will be necessary to engage in activities that reach beyond the clinical setting and incorporate community and public health systems.[4]

The Institute for Healthcare Improvement (IHI), a leading not-for-profit organization dedicated to using quality improvement strategies to achieve safe and effective health care, has developed the Triple Aim initiative[5] as a rubric for health care transformation. The three linked goals of the Triple Aim include improving the experience of care, improving the health of populations, and reducing per capita costs of health care.[6] However, although two of the three aims–experience of care and cost reduction–are self-explanatory, there is little consensus about how to define population health. Words like "panel management," "population medicine," and "population health" are being used interchangeably. Berwick et al.[6] describe the care of a population of patients as the responsibility of the health care system and use broad-based community health indicators as evidence of improvement. Other recent publications have attempted to describe population health from the hospital,[7–10] primary care,[11] and community health center perspectives.[12] The "clinical view" identifies the population as those "enrolled" in the care of a specific provider, provider or hospital system, insurer, or health care delivery network (i.e., panel population).[7] Alternatively, from the public health perspective,[8] population is defined by the geography of a community (i.e., community population) or the membership in a category of persons that share specific attributes (e.g., populations of elderly, minority population). In either case, the context of a community and the existing social determinants of health, ranging from poverty to housing, are known to have substantial impact on individual health outcomes. Thus, ensuring the health of a population is highly dependent on addressing these social determinants and requires collaborative relationships with community institutions outside the health care setting.[13,14]

Two key concepts that will greatly influence the definition and actualization of population health in the post-ACA era include the accountable care organization (ACO)[15] and the patient-centered medical home (PCMH).[16] The ACO represents an integrated strategy at the delivery system level to respond to payment reform.[15] These integrated systems of care are poised to manage a population of patients under a global payment model. The PCMH is focused on transforming primary care to better deliver "patient-centered" care and to address the whole patient, including their health and social needs.[17,18] Both models will need to identify, monitor, and manage their "population" of patients. However, their ability to extend their definition of population health to encompass the entire community will depend on resources, market share, and the strength and capacity of collaborating community and public health organizations. As integrated delivery systems are asked to do more than focus on their own patients, they will require additional resources. These may come from a realignment of existing programs (community benefits), a return on investment from effective preventive care, or collaborative relationships with existing community and public health organizations.

In this article, we discuss two major points regarding ACOs and their approach to population health. First, ACOs should be committed to serving the health of the people in the communities from which their population is drawn, and not just the population of patients enrolled in their care to achieve the population health goal. Second, to achieve this expanded definition of population health, ACOs will need to engage in collaborative efforts with community agencies and the public health system. We describe a "community" definition of population health to be used in lieu of the "panel" definition and then outline the resources needed and strategies for collaboration. Finally, we offer recommendations to assist ACOs in realizing their population health goal.