HLTH 1000 Week 7 Prevention Analysis Example

Primary, Not Secondary: Placing the National Diabetes Prevention Program's Lifestyle Change Program at One Level of Prevention, and the Screening Step That Belongs Elsewhere

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Walden University

HLTH 1000: Concepts of Health Promotion

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Month Day, Year

Primary, Not Secondary: Placing the National Diabetes Prevention Program's Lifestyle Change Program at One Level of Prevention, and the Screening Step That Belongs Elsewhere

Introduction

The lifestyle change program of the National Diabetes Prevention Program (National DPP) is primary prevention of type 2 diabetes. This paper defends that placement against the two levels it rejects, secondary and tertiary prevention, and then explains why one component of the program, the blood test used to find eligible participants, belongs at a different level.

The Three Levels of Prevention

The levels of prevention are defined by where they act in the course of a condition. Primary prevention acts before the condition exists, by reducing exposure to its causes or strengthening resistance to it. Secondary prevention acts while the condition exists but has not yet produced symptoms, by detecting it early so that treatment can begin sooner. Tertiary prevention acts after diagnosis, by limiting complications and disability. The criterion for each level is therefore the state of the condition at the moment the intervention acts: absent, present but undeclared or diagnosed.

Starfield et al. (2008) warn that these categories have blurred as risk factors, such as high blood pressure or high cholesterol, have come to be treated as diseases in their own right. When a risk factor is relabeled as an early form of disease, interventions aimed at it can be described as secondary prevention even though the disease itself has not begun. The placement below applies the criterion to the condition named in the program's title, type 2 diabetes, not to the risk state.

The Program

The National DPP lifestyle change program is a year-long group program for adults who have prediabetes or are at high risk of type 2 diabetes but do not have it. Participants meet with a trained lifestyle coach, weekly at first and then less often, and work toward two goals: losing at least 5% of body weight and reaching 150 minutes of physical activity a week. The program was established nationally after the Diabetes Prevention Program trial showed that an intensive lifestyle intervention lowered new-case rates for type 2 diabetes, compared with placebo, by 58% in adults whose blood glucose was elevated (Diabetes Prevention Program Research Group, 2002). It is delivered by community organizations, health systems and employers that meet the Centers for Disease Control and Prevention's recognition standards (Albright & Gregg, 2013).

The observable features that matter for placement are these: participants are enrolled because they do not have diabetes but are at elevated risk; the program changes diet, activity and weight; and its outcome is whether diabetes develops.

Testing the Program Against Each Level

Tertiary Prevention

Tertiary prevention requires a diagnosed condition. Participants in the lifestyle change program, by its eligibility rules, do not have diagnosed diabetes; people who already have type 2 diabetes are excluded. A program for people without the disease cannot be limiting its complications. Tertiary placement is ruled out on the program's own enrollment criteria.

Secondary Prevention

Secondary prevention is the serious rival. Prediabetes is detected by a blood test, much as early cancers are detected by screening, and some writers describe prediabetes as an early stage on the path to diabetes. If prediabetes is treated as early disease, the program looks like early treatment of a condition found by screening.

The argument fails on the criterion. Secondary prevention acts on a condition that exists but has not declared itself. Prediabetes is not undeclared diabetes; it is a state of elevated risk in which diabetes has not developed, and many people with prediabetes never progress to diabetes. Treating it as the disease is exactly the blurring Starfield et al. (2008) caution against. The program's outcome, too, is the incidence of diabetes, new cases that did not exist at enrollment. Secondary prevention is judged by earlier detection and better outcomes for a disease already present, while the DPP trial was judged by whether the disease occurred at all. The measure the program was built on is a primary prevention measure.

Primary Prevention

Primary prevention acts before the condition exists by reducing its causes. The program enrolls people without diabetes, acts on modifiable causes of diabetes, excess weight and physical inactivity, and measures success by fewer new cases. Each feature matches the criterion. In community delivery, results have been smaller than in the trial: an evaluation of 14,747 participants in the first four years found an average weight loss of 4.2%, with 35.5% reaching the 5% goal, and greater attendance was associated with more weight lost (Ely et al., 2017). A review of real-world programs modeled on the trial reached a similar conclusion about smaller but meaningful weight loss (Ali et al., 2012). Weaker results do not change the level, however. A program that reduces causes in people who do not have a disease is primary prevention whether it works well or poorly.

The Component That Belongs Elsewhere

One part of the pathway into the program does not fit the primary placement. To be referred, most participants first have a blood test, such as a hemoglobin A1c or fasting glucose test, which shows whether their blood glucose is in the prediabetes range. The same test also detects people whose glucose is already in the diabetes range and who did not know it. For those people, the test is secondary prevention: it finds an existing, undeclared condition so that treatment can begin. They are then excluded from the lifestyle change program and referred to diabetes care.

This means the screening step operates at two levels at once. For people found to have prediabetes, it is a way to identify who is eligible for primary prevention. For people found to have diabetes, it is secondary prevention in its classic form. The lifestyle change program itself remains primary prevention, but the pathway that feeds it includes a secondary prevention activity, and an honest description of the program should say so.

Conclusion

The National DPP lifestyle change program is primary prevention because it enrolls people without diabetes, acts on the causes of diabetes and counts success in cases that never develop. Tertiary placement fails on eligibility, and secondary placement fails because prediabetes is a risk state rather than undeclared disease. The screening test that identifies participants, however, also finds undiagnosed diabetes, and for those people it is secondary prevention. Placing a program at a level requires looking at each of its parts, because the components that bring people into a program may act at a different point in the course of disease than the program itself.

References

Albright, A. L., & Gregg, E. W. (2013). Preventing type 2 diabetes in communities across the U.S.: The National Diabetes Prevention Program. American Journal of Preventive Medicine, 44(4, Suppl. 4), S346-S351. https://doi.org/10.1016/j.amepre.2012.12.009

Ali, M. K., Echouffo-Tcheugui, J. B., & Williamson, D. F. (2012). How effective were lifestyle interventions in real-world settings that were modeled on the Diabetes Prevention Program? Health Affairs, 31(1), 67-75. https://doi.org/10.1377/hlthaff.2011.1009

Diabetes Prevention Program Research Group. (2002). Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine, 346(6), 393-403. https://doi.org/10.1056/NEJMoa012512

Ely, E. K., Gruss, S. M., Luman, E. T., Gregg, E. W., Ali, M. K., Nhim, K., Rolka, D. B., & Albright, A. L. (2017). A national effort to prevent type 2 diabetes: Participant-level evaluation of CDC's National Diabetes Prevention Program. Diabetes Care, 40(10), 1331-1341. https://doi.org/10.2337/dc16-2099

Starfield, B., Hyde, J., Gérvas, J., & Heath, I. (2008). The concept of prevention: A good idea gone astray? Journal of Epidemiology and Community Health, 62(7), 580-583. https://doi.org/10.1136/jech.2007.071027