Population health

Learning outcomes

By the end of this chapter, readers will be able to:

  • 1.

    Describe the United States health care evolution to population-based health.

  • 2.

    List the core functions of public health, including primary, secondary, and tertiary prevention.

  • 3.

    Discuss agencies and programs that assist physician assistants (PAs) in implementing and promoting disease prevention, including the Centers for Disease Control, the United States Preventative Services Task Force, and Healthy People.

  • 4.

    Identify stakeholder roles in the promotion of community health.

  • 5.

    Discuss ways PAs can incorporate the principles of community-based participatory research and community-oriented primary care in their practice to improve the health of their community.


In 2017, health care spending in the United States totaled $3.5 trillion, or $10,739 per person. Despite having the most expensive health care system in the world, the United States falls short on many of the metrics used to measure health. Compared with similar high-income and high-resource countries, the United States has higher infant and maternal mortality rates and a higher prevalence of chronic and debilitating diseases, such as heart disease, obesity, and diabetes. , In 2017, life expectancy for the U.S. population, which was already lower than many developed countries, declined in comparison with 2016.

A contributing factor to the disparity observed between U.S. health expenditures and health matrices is the shift in the burden of disease over the last century from acute and infectious diseases to chronic diseases. Seven of the ten leading causes of death in the United States in 2017 were chronic illnesses ( Box 47.1 ). Today, almost one in three Americans lives with at least two chronic physical or behavioral problems. The burden of chronic disease has a substantial impact on health care costs, with nearly 75% of all U.S. health care spending, and >90% of Medicare expenditures, going toward the treatment of patients with multiple chronic diseases. In addition to the financial cost, the rise in chronic diseases also places a burden on families and communities. Almost half of patients with multiple chronic illnesses have difficulty performing activities of daily living in the home, as well as trouble getting groceries and traveling to the pharmacy to fill their prescriptions.

Box 47.1

(From Murphy SL, Xu JQ, Kochanek KD, Arias E. Mortality in the United States, 2017. HCHS Data Brief, no 328. Hyattsville, MD: National Center for Health Statistics, 2018.)

Top 10 Causes of Death in the United States (Age Adjusted, 2017)

  • 1.

    Heart disease

  • 2.


  • 3.

    Unintentional injuries

  • 4.

    Chronic lower respiratory diseases

  • 5.


  • 6.

    Alzheimer disease

  • 7.


  • 8.

    Influenza and pneumonia

  • 9.

    Kidney disease

  • 10.


Although the United States is world-renowned for its advances in medical procedures, technology, and pharmaceutical development, the traditional U.S. medical approach designed to manage and care for patients with acute illnesses is inadequate for addressing and preventing chronic illness. The origins of chronic illness have their roots in complex social, behavioral, and environmental factors. As a result, the communities in which patients live have become a significant, but often overlooked, contributing factor to their health.

Growing recognition of the need to shift the current “treatment of illness” focus of U.S. medical care to one that focuses on “promotion of health” has led to an increased interest in a population health–based approach to health care. The concept of population health represents the combining of traditional U.S. medical practice with theories and practices that have historically been considered in the realm of public health. Population health places both a greater emphasis on the assessment and consideration of the social determinants that contribute to health and a stronger focus on health care outcomes. A population-based approach to medicine considers the environmental and social context of illness and integrates health promotion and prevention into routine health care ( Fig. 47.1 ). Population-based medicine involves the family and community in the treatment of patients and works to reduce health disparities and health care costs.

Fig. 47.1

Health is more than health care. County Health Rankings Model.

From University of Wisconsin Population Health Institute. County Health Rankings Model. 2014; https://www.countyhealthrankings.org/explore-health-rankings/measures-data-sources/county-health-rankings-model . Accessed June 2019.

Physician assistants (PAs) are poised to contribute to this partnership between medicine and public health by maintaining a perspective that emphasizes preventive medicine, identifies and corrects disparities, integrates behavioral and social sciences, and aims to improve the health of the population as a whole. PAs also have the opportunity to engage their communities and encourage community involvement in the health of the population.

Population health

Health care providers often focus time and attention on the individual-level actions and decisions that affect the health of patients. When seeing a patient with high blood pressure, a provider may write a prescription for antihypertensives, encourage regular physical activity, and educate the patient about the benefits of a balanced low-salt diet that includes multiple servings of fruit and vegetables daily. This prescribed intervention assumes the patient has all of the following: the resources to fill the prescription; a safe and convenient place to walk and exercise; access to a supermarket with fresh fruit and vegetables; a home with a working stove and refrigerator necessary to prepare healthy meals; and a family and community that supports and encourages the prescribed lifestyle changes. For some patients, the essential elements for a healthy life are readily available; for others, however, the ability to make healthy choices is significantly limited by their resources. Even if the patient has the resources to follow the prescribed regimen and it improves the health of that individual patient, this individual-level approach is unlikely to influence the health of that patient’s community and the larger population. To have the greatest impact on the health of the population, providers must also work to address the socioeconomic and neighborhood/environmental factors that pose obstacles to making healthy decisions and attaining optimal health, develop policies that normalize and support healthy behaviors, and promote health prevention measures ( Fig. 47.2 ).

Fig. 47.2

Health impact pyramid.

(From Frieden TR. A framework for public health action: the health impact pyramid. Am J Public Health. 2010;100(4):590-595.)

Core functions of public health

The Core Public Health Functions Steering Committee, made up of representatives from U.S. Public Health Service agencies and other major public health organizations, developed the Essential Public Health Services (EPHS) framework in 1994 ( Fig. 47.3 ). The three core functions of public health are: assessment , policy development , and assurance . Within each of these core functions, there is the opportunity for PAs to integrate these concepts into their own practices and partner with their public health colleagues to better the health of the population.

Fig. 47.3

Three core public health functions.

(From CDC. The public health system and the 10 essential public health services. https://www.cdc.gov/publichealthgateway/publichealthservices/essentialhealthservices.html . Accessed June 2019.)

The health status of each community is different; therefore it is necessary for public health officials to provide surveillance and monitoring of the health status metrics of the population to assess need and design intervention. In addition, local public health officials must work with community members to identify and address the perceptions, needs, and health priorities of the individual community. Rather than dictating what needs to be done, working with community members on shared goals can result in improved buy-in and better health outcomes. PAs contribute to public health assessment and surveillance activities by participating in mandatory reporting. PAs can also engage with their communities and facilitate partnerships between patients, other health care providers, public health organizations, and community leaders to encourage health promotion activities.

Public health officials work to develop and advocate for policies and laws that create healthier “default” environments that affect the health of populations, regardless of individual decision making. , Examples of high-impact public health policies include the banning of smoking in public areas, laws that limit or prevent lead and asbestos exposures, seatbelt laws, and the elimination of trans fat in foods. Other public health policies that facilitate or encourage individuals to make healthy decisions include designing public spaces that promote physical activity; improving access to public transit; instituting bike lanes and paths; clarifying food labels; and taxing sugar-sweetened beverages, alcohol, and tobacco. PAs, through engagement with their communities and involvement with the American Academy of Physician Assistants (AAPA) and state and local constituent AAPA chapters, can stay informed about and advocate for policy initiatives designed to improve population health at both national and local levels.

The third core public health function involves assuring a competent public and personal health care workforce and linking individuals to appropriate health services and resources. Assurance also involves ongoing evaluation to assess the effectiveness, quality, and accessibility of personal and population-based health services. By identifying what works and what does not, resource allocation can be optimized, and alterations and adjustments can be made to better serve the needs of the population. Practicing PAs have the knowledge and skills to serve as patient and community advocates. Collaborations between PAs, public health officials, and community members can enhance patient access to and the quality of community-based health services.

Primary, secondary, and tertiary prevention

Chronic diseases are among the most prevalent and costly health-related problems facing the United States. Fortunately, the chronic conditions and risk factors that contribute the most to death and disability are also among the most preventable ( Box 47.2 ). There are three approaches to prevention: primary, secondary, and tertiary. The primary prevention approach focuses on preventing disease before it develops; secondary prevention attempts to detect a disease early and intervene early; and tertiary prevention is directed at managing established disease in someone and avoiding further complications.

Box 47.2

Institute for Health Metrics Evaluation. Used with permission. All rights reserved.

The Risk Factors That Drive the Most Death and Disability Combined in the United States

  • 1.

    High body-mass index

  • 2.


  • 3.

    Dietary risks

  • 4.

    High fasting plasma glucose

  • 5.

    High blood pressure

  • 6.

    Drug use

  • 7.

    Alcohol use

  • 8.

    High low-density lipoproteins

  • 9.

    Impaired kidney function

  • 10.

    Occupational risks

The goal of primary prevention is to take action to prevent the development of a disease or injury in a person who is “well.” Primary prevention has the potential to reach large portions of the population, and can therefore have a substantial impact on the population’s health while remaining cost effective. Examples include the routine immunization of healthy people against communicable diseases such as measles and influenza. Primary prevention efforts can take place at both the individual and population/policy development levels. For example, although selection of fruits and vegetables, whole grains, and low-fat foods are individual-level prevention measures, taxation of sugar-sweetened beverages and requirements that calorie counts be included on fast-food restaurant menus are policy-level measures aimed at promoting healthy choices and primary prevention.

The goal of secondary prevention is to identify individuals for whom a disease process has already begun, but who remain asymptomatic. Secondary prevention includes following the United States Preventive Services Task Force (USPSTF)’s evidence-based recommended screenings for cancer, diabetes, obesity, hypertension, and the like, with the aim of identifying a disease when it is still asymptomatic. Early identification of a disease through screening permits earlier intervention, and ideally, an improved chance of a cure and/or reductions in morbidity and mortality associated with the disease.

Tertiary prevention involves the prevention of complications in people who have already developed disease, and in whom disease prevention is no longer an option. For these patients, the goal of tertiary prevention is to maximize the outcomes and prevent further morbidity from the disease process. An example might include initiating cardiac therapy and rehabilitation in a patient who experienced a myocardial infarction. The damage to the heart cannot be reversed; however, with appropriate cardiac therapy and rehabilitation, the patient will be able to maximize his or her cardiac output and prevent further morbidity and mortality associated with the myocardial infarction.

Historically, the majority of health care time and resources have been provided in the tertiary prevention stage, but to decrease health care expenditures and have the greatest impact on improving the health of both individuals and the population, all three of these prevention methods should be optimized ( Table 47.1 ). Three federal agencies and programs that can assist PAs and other health care providers with health promotion and disease prevention are the USPSTF, the Centers for Disease Control and Prevention (CDC), and the Healthy People program.

Jun 15, 2021 | Posted by in MEDICAL ASSISSTANT | Comments Off on Population health

Full access? Get Clinical Tree

Get Clinical Tree app for offline access