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

Defining Population Health

Population health connotes a high-level assessment of a group of people.[9] This epidemiological framework is often in direct opposition to the manner in which the health care system has cared for patients in a fee-for-service model: one individual at a time. Currently, population health is being seen in two distinct ways: (1) from a public health perspective, populations are defined by geography of a community (e.g., city, county, regional, state, or national levels); and (2) from the perspective of the delivery system (individual providers, groups of providers, insurers, and health delivery systems), population health connotes a "panel" of patients served by the organization.

In the post-ACA world, as payment models shift from fee-forservice to global payment, ACOs will necessarily reorient from a disease focus to a wellness focus to improve quality and contain costs. Although they will have an ethical and contractual obligation for the patients for which they care, their engagement in the larger community may be highly dependent on which members of the community population actually end up being part of a particular ACO or PCMH panel. The larger the overlap between an ACO panel and the community population, the more the overall health of the community will contribute to the ACOs' ability to keep their patients healthy. Similarly, the larger the overlap between community population and ACO panel, the more ACO health outcomes will drive community health indicators. Table 1 displays how an ACO might address a variety of characteristics, depending on the chosen definition of population health (none, panel of patients in the delivery system, all members of a community).


As provider organizations are asked to embrace the broader community definition of population health, resources will be needed to support this role. These resources include access to data, funding, and collaborative relationships.

Data. With the emergence of the electronic medical records, ACOs should become more facile at viewing their population as a whole and identifying trends across their panel's health (age, gender, race, chronic conditions). The data needed for this endeavor are largely collected at the visit level by registration and clinical staff. With adequate health information technology, systems can now examine issues such as risk for future disease, comorbidities, and quality metrics across a defined population. Using these data, the ACO can also determine the zip codes and communities where a majority of their patients reside and compare their health indicators to the community health indicators for the same geography.

Data on community health indicators (e.g., preventive services use, infectious disease rates, lead paint exposure, occupational health issues, cancer rates, births, and deaths from vital statistics) are more accessible than ever before. The National Prevention Strategy[19] and the Healthy People 2020 goals for the nation[20] include health indicators for population health at the community level. Much of community health information resides with state and county or city health departments, some of which have online interactive data tools that are available to the public (MassCHIP-Massachusetts[21]). New tools, such as the County Health Rankings[22] and the Community Health Status Indicators,[23] are publicly available and allow users to obtain county-level health data. In some jurisdictions, provider organizations are identifying ways to share de-identified data with community health leaders to jointly identify priority prevention strategies.[24]

Funding. ACOs will also need to identify financial resources to achieve population health goals. The current fee-for-service structure does not support population health efforts, and although demonstration grants may help, they cannot sustain ongoing work. Today, nonprofit hospitals are required to provide some support for community programs through the recently revised community benefit in the ACA.[25] Realigning hospital community benefit programs with population health efforts can help support the expanded role.

Simultaneously, ACOs need to assess which preventive strategies will yield the best return on investment (ROI) for their patients. Evidence-based services that demonstrate ROI and improved health outcomes can help in this endeavor. Nationally, two sets of evidenced-based prevention services have been identified: clinical preventive services, such as mammography, immunizations, and smoking cessation;[26] and community preventive services, such as fluoridation, lead testing, and community screening.[27] Many of the clinical preventive measures are considered quality measures by major accrediting systems (e.g., Healthcare Effectiveness Data and Information Set or the National Committee for Quality Assurance) and are also included in health coverage under the ACA. Assuming an ROI is realized, dollars saved can shift to support community and public health initiatives. Additionally, the federal public health trust fund provides a new revenue stream to support prevention strategies directly tied to health improvement and cost containment.[28] This was recently replicated in Massachusetts with the passage of Chapter 224.[29]

Collaboration. Many of these evidence-based prevention practices fall within the purview of community agencies and the public health system outside of ACO responsibility. For example, smoking bans promulgated by public health authorities have affected smoking rates and secondhand smoke exposure and have led to lower risk of hospitalization for cardiac and pulmonary conditions.[30] Therefore, ACOs that strive to improve population health within geography will need to develop partnerships to support prevention activities while integrating complementary efforts into clinical settings. In particular, the ACO's relationship with the local public health authority or authorities is essential. Although the public health authority is not the only organization with which an ACO will need to collaborate, it is the only agency that has legal authority and mandates to protect, promote, and assure the health for every individual in the community.[31]Despite the logic of this partnership, integrating public health and the delivery system has proven difficult.[32,33] Today, the ACA poses an unprecedented opportunity to refocus these efforts. While ACOs are contemplating the best strategies for population health improvement, public health authorities are also recognizing their changing roles[34,35] and their need to effectively align with providers.[36] As health insurance expands, public health clinical services are likely to decrease, and core functions including surveillance, regulation, and quality assurance will be more important than ever before. States such as Massachusetts, Minnesota, Washington, and Vermont have already evolved from delivering direct services to providing "wrap around" services (e.g., outreach, care coordination) and maintaining the core public health functions. Under global payment models, ACOs will depend on public health authorities to address regulatory and policy issues that have wide-reaching health impact.[37]

Figure 1 presents three possible relationships between health delivery and public health systems. When a community is served by one health system and one public health authority, integration efforts may be more easily achieved. However, in other cases, the delivery system will need to work with a number of public health authorities or the public health authority will need to work with numerous delivery systems.

Figure 1.

Relationships between integrated delivery system and public health system.

Strategies to Overcome Obstacles

To achieve alignment between provider organizations and community and public health agencies, strategies are needed to overcome multiple obstacles. For example, in highly competitive environments with multiple providers, a strategy of cooperation between clinical delivery systems and community and public health agencies is required to jointly improve population health. The Institute of Medicine report, Improving Health in the Community[38] presented a method for multiple stakeholders in a community coming together to "share accountability" for population health outcomes. Weak public health infrastructure is another obstacle, and in these cases, the delivery system may need to shore up core public health functions (assurance, assessment, policy).[31] In communities with strong public health systems, public health can address health from a policy and regulatory perspective while the health care system provides individual clinical prevention and treatment.[37,39] ACOs may lack the appropriate skills and resources to achieve population health goals, posing another challenge. A strategy that identifies and connects an ACO to community and public health resources can enhance population health efforts. For example, many community and public health agencies have extensive experience and programs serving vulnerable populations and can assist ACOs in their outreach efforts. Overall, ACOs and public health systems can play complementary roles in improving population health goals as seen in the following examples.

  1. An urban ACO serving a large city works with a local public health authority to identify geographic pockets of patients with diabetes. The ACO focuses on improved diabetes management in the clinical setting while linking to community resources for patients requesting exercise and physical activity options. Public health can lead a campaign to improve access to fresh fruits and vegetables and change policies related to menu labeling.

  2. An ACO serving a number of suburban communities identifies high use of the emergency room from alcohol-related issues in young adults as a focus for improvement. Working with the public health authority, local schools, and substance abuse agencies, the collaboration creates a safe rides program and develops policies to monitor underage liquor sales.

  3. An ACO serving a large rural population has trouble providing enough access for immunizations to elders. Communitywide access to immunizations is provided by working with the public health authority and local pharmacies. Communication strategies that link pharmacies and public health to the ACO are developed, along with an immunization registry for public health population-level surveillance.


It will take time for newly emerging ACOs to develop meaningful collaborative relationships with public health entities. We recommend the following steps for ACOs:

  • Determine in which geographic communities patients reside and what the overlap is between the ACO panel and the community population.

  • Compare the health of the population served by the ACO with that of the community.

  • Decide what level of overlap in any geographic area merits collaboration. The more market share an ACO has in the area, the more investment in collaboration might be made, and the more impact that investment will have on health outcomes.

  • Engage in collaboration with public health and key community agencies, including conducting a joint needs assessment.

  • Collaboratively select health outcomes for focus.

  • Set up a formal agreement with the public health authorities to share data and monitor progress toward goals in clinical and community settings.

  • Identify population health indicators to be included on the ACO dashboard.

  • Use a portion of global payment fee to support community public health activities.