Chapter Five: Population Health

Introduction

The Centers for Disease Control and Prevention (CDC) defines population health as an interdisciplinary, customizable approach that allows health departments to connect practice to policy for change to happen locally (CDC, 2020). Different sectors of the community—public health, industry, academia, health care, local government entities, and many more—form nontraditional partnerships to achieve positive health outcomes. Population health “brings significant health concerns into focus and addresses ways that resources can be allocated to overcome the problems that drive poor health conditions in the population” (CDC, 2020).

Population health is slightly different from public health because public health works to protect and improve the health of communities through policy recommendations, health education and outreach, and research for disease detection and injury prevention. Public health can be defined as what “as a society [we] do collectively to assure the conditions in which people can be healthy” (Institute of Medicine, 1988). Population health, in contrast, provides “an opportunity for health care systems, agencies and organizations to work together in order to improve the health outcomes of the communities they serve” (The George Washington University, 2015).

What is Population Health?

The United States has the costliest health care system in the world, yet many countries consistently outperform the United States in terms of quality of care, health outcomes, and health expenditures. In 2008, researchers and policymakers suggested three aims that would significantly improve health care in the United States. This “Triple Aim” includes the following three goals:

1. Improving the patient experience of care (including quality and satisfaction)
2. Improving the health of populations
3. Reducing the per capita cost of health care (Berwick et al., 2008)

In 2014, the “Quadruple Aim”—adapted from the widely accepted Triple Aim—was suggested as a framework to optimize health care system performance (Figure 5.1). The framework encompasses reducing costs and improving population health and patient experience with a new fourth domain: promoting health care team well-being. During this time, researchers began to understand that the performance and quality pressures placed on nurses and other care team members were causing deleterious effects on their physical and mental health as well as reductions in the quality and costs of health care. Therefore, the fourth aim to improve our health system focused on provider well-being, stress reduction, burnout prevention, quality of life, and mindfulness (Arnetz et al., 2020).

Most recently, in 2022, a “Quintuple Aim” was proposed to include advancing health equity as the fifth U.S. health system improvement goal. To read more about the proposed Quintuple Aim, visit this article in the Journal of the American Medical Association (JAMA): The Quintuple Aim for Health Care Improvement A New Imperative to Advance Health Equity (Nundy et al., 2022).

To learn more about achieving health equity, see Chapter 2.

Population health focuses on preventing and managing costly, prevalent chronic diseases. The specific goals of population health are designed to achieve large-scale health improvements within neighborhoods, cities, counties, regions, or states. Population health measures target fundamental and often multiple determinants of health by addressing chronic diseases at the group level instead of the individual level. Population health evaluates current infrastructure, leverages available resources, mobilizes collective action efforts with multiple stakeholders, and through targeted actions seeks to have an impact on key health metrics such as premature death, air and water quality, tobacco use, and homelessness.

The Agency for Healthcare Research and Quality (AHRQ) defines population health as “measures that address health issues of individuals or populations defined by residence in a geographic area or a relationship to organizations that are not primarily organized to deliver or pay for health care services (such as schools or prisons)” (AHRQ, 2018). When we think of a population, we often think of a geographic area. However, in terms of population health, populations can also include people with similar characteristics, such as those who are incarcerated or people who inject drugs. For example, a public health nurse could focus their work on improving health outcomes for people who inject drugs by working to implement syringe exchanges. Figure 5.2 is a pictorial model of population health. On the left are multiple health factors (or determinants of health), and on the right, health outcomes. What is missing from this picture are people who are living healthy lives and not experiencing morbidity or early death. Also missing from this picture is causality. Causality means that one variable, such as a health factor, causes another variable, such as a health outcome, to occur. It is important to note that in some cases, variables are correlated, but one does not necessarily cause the other.

Long Description for Figure5.2

The percentage of each factor that contributes to health is as follows. Physical environment, 10 percent which includes air and water quality, 5 percent, and housing and transit, 5 percent. Clinical care 20 percent. It comprises access to care, 10 percent, and quality of care, 10 percent. Social and economic factors, 40 percent. It comprises community safety, 50 percent; employment, 5 percent; family and social support, 5 percent; income, 10 percent; education, 10 percent. Health behaviors, 30 percent. It includes tobacco use, 10 percent; diet and exercise, 10 percent; alcohol and drug abuse, 5 percent; poor health, 5 percent. Morbidity, 50 percent. It includes poor behavioral health days, 10 percent; low birth weight, 20 percent; poor physical health days 10 percent; poor health, 10 percent.

Population Health Quality Measures

Measures are applied to groups of persons identified by geographic location, organizational affiliation, or nonclinical characteristics to assess public health programs, community influences on health, or population-level health characteristics that may not be directly attributable to the care delivery system. These measures are supported by evidence demonstrating that they indicate the better or worse performance of population health activities (Table 5.1).

Related Population Health Measures

Some population health measures will be applied to a group of people to assess public health programs, community influences on health, or population-level health characteristics that are not related to health care initiatives. These measures are not supported by evidence demonstrating a link to better or worse performance of population health activities (Table 5.2).

Population Efficiency Measures

Measures that may be used to assess efficiency directly (e.g., by comparing a measure of quality with a measure of resource use) or indirectly (e.g., by measuring the frequency with which population health processes are implemented that have been demonstrated by evidence to be efficient; Table 5.3).

Population Health Strategies

The strategies for population health are as vast and varied as the populations they serve. Strategies for achieving better population health include:

• Understanding indicators and key metrics of health
• Engaging community stakeholders to act
• Assessing the needs and risks within the population or community
• Identifying evidence-based actions to improve health on a population scale
• Developing a shared vision, priorities, and plans amongst stakeholders
• Committing to shared resources and responsibilities
• Coordinating the implementation of health improvement programs
• Evaluating the effectiveness of processes and programs through community-based discussions and reevaluation of key health metrics

Effective population health strategy always begins with an evaluation of the population health data, using reputable sources, to determine the strengths and opportunities for a particular population. This begins with knowledge of where to find relevant sources of data and how to evaluate the data to understand the needs of the populations served. Sources of data typically include government organizations, nongovernmental organizations, research literature, academic centers of excellence, and others.

Benefits of a Population Health Approach

In 2014, Halfon and colleagues described a path for the evolution of the U.S. health care system from an Acute System (episodic, nonintegrated care) to a Coordinated, Seamless Health Care System (outcome-accountable care) to a Community-Integrated Health Care System (Halfon et al., 2014). These stages mirror the three buckets of prevention: traditional clinical prevention, innovative clinical prevention, and total population or community-wide prevention. The portfolios of population health framework (Figure 5.3), adapted from Institute for Healthcare Improvement (2022), builds on this important foundation with several modifications based on experience with supporting health care organizations in their efforts to improve population health.

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Population management includes P 1, physical and or mental health, and P 2, social and or spiritual well-being. Community well-being creation includes P 3, community health and well-being, and P 4, communities of solutions. Equity connects to all aspects of the framework.

Examples of Population Health Programs and Initiatives

The Health Impact in 5 Years (HI-5) initiative highlights nonclinical, community-wide approaches that have evidence reporting positive health results within 5 years, and cost-effectiveness and/or cost savings over the lifetime of the population (CDC, 2022).

The health outcomes that HI-5 interventions can prevent or reduce are presented in the following list, which demonstrates the broad health impact that community-wide approaches can have:

• Anxiety and depression
• Asthma
• Blood pressure
• Bronchitis
• Cancer
• Cardiovascular disease
• Child abuse and neglect
• Cognitive development
• Infant mortality
• Liver cirrhosis
• Motor vehicle injuries
• Obesity
• Dental caries
• Pneumonia
• Sexually transmittable infections
• Sexual violence
• Teenage pregnancy
• Traumatic brain injury
• Type II diabetes
• Youth violence (CDC, 2022)

Many programs and initiatives focus on population health at the local, city, state, national, and global levels. Just as many programs exist that focus on specific disease states or metrics across multiple population levels. It is important to recognize that all these programs and initiatives are important drivers of change and that each contributes in small and large ways to improve population health.

The public health impact pyramid in Figure 5.4 highlights the different types of public health interventions, starting with those that have the greatest potential to affect health. The pyramid can be applied to any setting, but this scenario is applied to issues affecting children.

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The layers of the pyramid represent the interventions as follows, from the base to the apex. Social determinants of health, HI-5, which includes early childhood education, clean diesel bus fleets, public transportation system, home improvement loans and grants, earned income tax credits, and water fluoridation. The next level is changing the context, or making the healthy choice the easy choice, which includes School-based programs to increase physical activity. School-based violence prevention. Safe routes to school. Motorcycle injury prevention. Tobacco control interventions. Access to clean syringes. Pricing strategies for alcohol products. Multi-component worksite obesity prevention. The top three levels are Long-standing protective interventions. Clinical interventions. Counseling and education.