GOALS AND APPROACHES TO PREVENTION
Prevention of acute and chronic diseases before their onset has been recognized as one of the hallmarks of excellent medical practice for centuries, and is now used as a metric for highly functioning healthcare systems. The ultimate goal of preventive strategies is to avoid premature death. However, as longevity has increased dramatically worldwide over the last century (largely as a result of public health practices), increasing emphasis is placed on prevention for the purpose of preserving quality of life and extending the healthspan, not just the lifespan. Given that all patients will eventually die, the goal of prevention ultimately becomes compression of morbidity toward the end of the lifespan; that is, reduction of the amount of burden and time spent with disease prior to dying. As shown in Fig. 2-1, normative aging tends to involve a steady decline in the stock of health, with accelerating decline over time. Successful prevention offers the opportunity both to extend life and to extend healthy life, thus “squaring the curve” of health loss during aging.
Loss of health with aging. Representation of normative aging with loss of the full stock of health with which individuals are born (indicating gain of morbidity), contrasted with a squared curve with greater longevity and fuller stock of health (less morbidity) until shortly before death. The “squared curve” represents the likely ideal situation for most patients.
Prevention strategies have been characterized as tertiary, secondary, primary, and primordial. Tertiary prevention requires rapid action to prevent imminent death in the setting of acute illness, such as through percutaneous coronary intervention in the setting of ST-segment elevation myocardial infarction. Secondary prevention strategies focus on avoiding the recurrence of disease and death in an individual who is already affected. For example, tamoxifen is recommended for women with surgically treated early-stage, estrogen-receptor-positive breast cancer, because it reduces the risk of recurrent breast cancer (including in the contralateral breast) and death. Primary prevention attempts to reduce the risk of incident disease among individuals with a risk factor. Treatment of elevated blood pressure in individuals who have not yet experienced cardiovascular disease represents one example of primary prevention that has proven effective in reducing the incidence of stroke, heart failure, and coronary heart disease.
Primordial prevention is a more recent concept (first introduced in 1979) which focuses on prevention of the development of risk factors for disease, not just prevention of disease. Primordial prevention strategies emphasize upstream determinants of risk for chronic diseases, such as eating patterns, physical activity, and environmental and social determinants of health. It therefore encompasses medical treatment strategies for individuals as well as a strong reliance on public health and social policy. It is increasingly clear that primordial prevention represents the ultimate means for reducing the burden of chronic diseases of aging. Once risk factors develop, ...