Examples of primary prevention in public health

Primary, Secondary, and Tertiary Prevention

In discussing prevention, it is helpful to distinguish among primary, secondary, and tertiary prevention (Table 1.2).

Primary prevention denotes an action taken to prevent the development of a disease in a person who is well and does not (yet) have the disease in question. For example, we can immunize a person against certain diseases so that the disease never develops or, if a disease is environmentally induced, we can prevent a person's exposure to the environmental factor involved and thereby prevent the development of the disease. Primary prevention is our ultimate goal. For example, we know that most lung cancers are preventable. If we can help to stop people from ever smoking, we can eliminate 80% to 90% of lung cancer in human beings. However, although our aim is to prevent diseases from occurring in human populations, for many diseases, such as prostate cancer and Alzheimer disease, we do not yet have the biologic, clinical, or epidemiologic data on which to base effective primary prevention programs.

Secondary prevention involves identifying people in whom a disease process has already begun but who have not yet developed clinical signs and symptoms of the illness. This period in the natural history of a disease is called thepreclinical phase of the illness and is discussed inChapter 18. Once a person develops clinical signs or symptoms it is generally assumed that under ideal conditions the person will seek and obtain medical advice. Our objective with secondary prevention is to detect the disease earlier than it would have been detected with usual care. By detecting the disease at an early stage in its natural history, often through screening, it is hoped that treatment will be easier and/or more effective. For example, most cases of breast cancer in older women can be detected through mammography. Several recent studies indicate that routine testing of the stool for occult blood can detect treatable colon cancer early in its natural history but colonoscopy is a better test, although far more expensive and invasive. The rationale for secondary prevention is that if we can identify disease earlier in its natural history than would ordinarily occur, intervention measures may be more effective and life prolonged. Perhaps we can prevent mortality or complications of the disease and use less invasive or less costly treatment to do so. Evaluating screening for disease and the place of such intervention in the framework of disease prevention are discussed inChapter 18.

Tertiary prevention denotes preventing complications in those who have already developed signs and symptoms of an illness and have been diagnosed (i.e., people who are in the clinical phase of their illness). This is generally achieved through prompt and appropriate treatment of the illness combined with ancillary approaches such as physical therapy that are designed to prevent complications such as joint contractures.

Tertiary Prevention

Tertiary prevention seeks to reduce the impact of established disease by eliminating or reducing disability, minimizing suffering, and maximizing potential years of quality life. In epidemiological terms, tertiary prevention aims to reduce the number and/or impact of complications. This is the task of therapy and rehabilitation.

Strategies for tertiary prevention include screening of patients with diabetes for diabetic retinopathy to prevent progression to blindness through prompt treatment; prevention of opportunistic infections in HIV patients; provision of prostheses and medical devices to enable persons to take part in social life; follow-up of chronically ill patients to ensure adherence to medication regimen, monitor changes, and assist them in maintaining independence in daily life; rehabilitation of stroke patients to restore functions, such as through physiotherapy, and prevent recurrence or further complications through appropriate medication.

Tertiary prevention is often difficult to separate from treatment. Several authors refer to the treatment of, for example, symptomatic cancer or surgical interventions for acute conditions such as appendicitis as tertiary prevention because these interventions seek to prevent recurrence of disease and, ultimately, reduce case fatality.

Answers and explanations

1.

B. Tertiary prevention is the prevention of disease progression and complications that might result in further impairment, and it comprises rehabilitation to reverse impairment and disability. Occupational therapy is a form of rehabilitation directed at preventing disability after a stroke and is an example of tertiary prevention. The treatment of essential hypertension (D) is best considered a form of secondary prevention, although arguably might constitute primary prevention of ischemic heart disease or cardiomyopathy. Postexposure prophylaxis (C) for rabies is secondary prevention, preventing possibly contracted disease from becoming manifest. Using nasal steroids with topical decongestants (E) is a method for primary prevention of rebound congestion. Hospice care (A) is intended to provide comfort during the late stages of terminal illness and does not specifically have the goal of preventing disease progression.

C. The management of communicable diseases such as tuberculosis offers a unique opportunity for prevention. When a patient with active disease is treated, the progression of disease and impairment are prevented in the patient; this is tertiary prevention. At the same time, the spread of disease to the patient’s various social contacts is prevented; this is primary prevention in a different individual. Thus primary and tertiary prevention are not mutually exclusive (A) and, in fact, can even occur in the same person. For instance, dietary measures used to prevent the progression of coronary artery disease after a heart attack (E) might serve as primary prevention for the development of diabetes for the same person. Likewise, giving antibiotics for cystitis (D) could conceivably prevent other infections, and rehabilitating a broken hip (B) could increase balance, flexibility, strength, and agility to prevent other musculoskeletal injuries from developing.

C. Multiple sources suggest that smoking increases the risk of age-specific cardiovascular mortality by a factor of approximately 2. Cigarette smoking is generally considered the most important preventable cause of death and disease in the United States. The risk of myocardial infarction is certainly higher (A) with smoking, and definitely more than a third higher (B), but probably not 10 (D) or 100 (E) times as high.

A. High-density lipoprotein levels are inversely associated with the risk of cardiovascular disease (although emerging evidence challenges causality). All other lipid fractions contributing to the total cholesterol level have been associated directly, to varying degrees, with cardiovascular disease risk. The TC level includes several generally positive correlates and one generally negative correlate (HDL) of heart disease risk, and this mix of “bad” and “good” reduces the utility of the total. The ratio of TC to HDL purifies the measure somewhat, so that a positive correlate of cardiovascular disease risk is produced. Total cholesterol can be easily measured (C) and is part of the reason for the original association between TC and heart disease (a weak association). The levels of TC do not fluctuate wildly (D) or vary much with meals (E); in fact, contrary to popular belief, dietary cholesterol has almost no impact on serum cholesterol. The ratio of LDL to VLDL (B) highlights that oversimplifying associations based on single categories of lipids almost always misses the mark; the more we understand about the heterogeneity within categories, the more the difference and relative proportions seem to matter a great deal.

B. The one class of drugs that has a compelling indication for all the listed conditions is ACE inhibitors. Generally, angiotensin receptor blockers (ARBs) are acceptable alternatives when ACE inhibitors are not tolerated, although the evidence supporting this drug class for most conditions is not as robust as for ACE inhibitors. Alpha blockers (A) do not have a compelling indication for any of the listed conditions. Calcium channel blockers (C) have compelling indications for high cardiovascular disease risk and diabetes, but side effects (leg swelling, constipation) often limit their utility, particularly in older patients. Thiazide diuretics (D) are recommended expressly for all listed conditions except chronic kidney disease and treatment after heart attack. Thiazides are effective, affordable, and a usual part of the antihypertensive regimen for most people. Beta blockers (E) have a compelling indication for heart failure, treatment after heart attack, and diabetes. In people without compelling indication, beta blockers are falling out of favor for first line treatment of high blood pressure (meta-analyses suggest they may be associated with an increase in risk of cardiovascular events and death).

E. In the 1990s the DCCT was designed specifically to test the hypothesis that tight glycemic control couldforestall microvascular complications of diabetes. The trial showed that the closer to normal that serum glucose and glycohemoglobin levels were maintained, the less the progression of microvascular complications such as retinopathy (eye damage) and nephropathy (kidney damage). Thus microvascular complications of diabetes do not seem to be independent of glycemic control (A) and do seem to be preventable (C). Greater effort is now devoted to achieving near-normal control of serum glucose levels when feasible, although this increases the risk of hypoglycemia. The risk of hypoglycemia may not outweigh the benefit of tight glycemic control (D). In fact, striving for tighter control of blood sugar is associated with increased mortality in some populations (e.g., intensive care unit patients, patients at high risk for CVD). Monitoring the urine glucose level is not more cost effective than monitoring the blood glucose level (B). In fact, monitoring urine glucose is useless in cases of tight control, because glucose generally does not appear in the urine until blood level exceeds about 200 mg/dL (200 mmol/L), levels far above what would be considered tight control.

B. Before renal function begins to decline as a result of diabetic nephropathy, there is a period during which glomerular filtration increases because a high osmotic load is delivered to the glomerulus. Renal hyperfunction is associated with microalbuminuria and presages a decline in creatinine clearance (an accepted measure of kidney function and filtering capacity). Evidence is now substantial that ACE inhibitors attenuate renal hyperfunction in diabetic patients, mitigate the associated microscopic proteinuria, and slow the subsequent decline in glomerular filtration (i.e., slow the progression of diabetes-related kidney damage). Sulfonylureas (A) and insulin (D) may indirectly slow the progression of nephropathy by providing tight glycemic control, but the mechanisms through which diabetes produces kidney damage likely involve factors other than just blood sugar. Dialysis (C) is life-sustaining therapy after renal failure has occurred, but has no role in the management of early microalbuminuria, when kidney function is still mostly preserved. Lifestyle modification (E) may contribute to better glycemic control and management of the metabolic derangements associated with diabetes, but there is no evidence that lifestyle measures will be as effective in preserving renal function as ACE inhibitors.

A. Tertiary prevention consists of rehabilitation and efforts to prevent disease progression after an injury or event has occurred. After the event of a stroke, physical therapy is a form of rehabilitation and a means of preventing further impairment and disability. In the United States the incidence of strokes has been decreasing for several decades, not increasing (B). More importantly, however, whether strokes occur more often in a population is not a concern to a person who has already had a stroke; tertiary prevention occurs after an injury (stroke in this case). Incidence of a first stroke would be a concern for primary and secondary prevention, not tertiary prevention. Likewise, whether the risk factors for a first stroke are known is not related to tertiary prevention, because the event has already occurred and the focus is now on limiting disability, maximizing function, and preventing recurrence. To prevent recurrence, understanding risk factors is important, but the risk factors for a primary event may be different than those for a repeat event, so the risk factors of concern in this case are not those for a first stroke (C), which has already occurred, but those for a second stroke. For stroke though, the risk factors for first and subsequent events are similar and well established, including hyperlipidemia and carotid stenosis. Treatment of hyperlipidemia (D) certainly may be a component of tertiary prevention but would not be predominant (e.g., treating blood pressure would be more important). Screening for carotid stenosis (E) is secondary prevention by definition (detection of asymptomatic disease). Once a stroke has occurred though, it is impossible to screen; one could look for carotid stenosis, but this would now be a diagnostic evaluation.

D. Disease refers to a medical diagnosis, or an objective description of a condition. Disability refers to the impact a condition has on a patient in objective terms. Illness is the subjective impact of a disease or condition on a patient—that is, how patients perceive themselves and their disease and disability. These two soldiers have the same disease or condition (facial and body burns). They also have the same disability (comparable disfigurement). The difference is their illness, or their perceptions and how their disease and disability is affecting them. Given these considerations, answer D is the only choice that is correct. The expectations surrounding the impact of the illness, its impact on functioning, and its duration are mediated through illness perceptions. Impacting illness perceptions is crucial for successful rehabilitation.

4.3 Polyphenols in Tertiary Prevention

Tertiary prevention is designed to reduce the limitations of disability from disease.5,9 Because human intervention and clinical studies are limited, the application of polyphenols in tertiary prevention is relatively unknown. However, there is potential, particularly with regard to metabolic syndrome—including hyperglycemia, dyslipidemia, and elevated blood pressure—that polyphenolic compounds in green tea may possibly alleviate these symptoms.7 Also, polyphenolic extracts from the tropical plant Hibiscus sabdariffa have demonstrated anti-insulin resistance properties, making the extract a potential aid in diabetic therapy, upon further research.8

Primary, secondary, and tertiary prevention

Chronic diseases are among the most prevalent and costly health-related problems facing the United States.4 Fortunately, the chronic conditions and risk factors that contribute the most to death and disability are also among the most preventable (Box 47.2).9 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.10

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.11 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.

Tertiary prevention

Tertiary prevention aims to soften the impact of long-term disease and disability by eliminating or reducing impairment, disability, and handicap; minimizing suffering; and maximizing potential years or useful like. The tertiary prevention is the task of treatment for late symptomatic disease and rehabilitation.16

Rehabilitation is the combined and coordinated use of medical, social, educational, and vocational measures for training and retraining patients to the highest possible level of functional ability. Recent studies suggest four types of rehabilitation: medical, social, vocational, and psychologic rehabilitations. Each type not only plays a unique role in rehabilitation treatment for a late symptomatic disease, but they also have multiple interactive effects on the results of the rehabilitation.

Tertiary Prevention

Tertiary prevention refers to preventing the progression of existing conditions (see Table 5.5). It “relates to functional assessment and rehabilitation both to reverse and to prevent progression of the burden of illness” (p. 3).41 Brownson and Scaffa18 defined tertiary prevention as “treatment and service designed to arrest the progression of a condition, prevent further disability, and promote social opportunity” (p. 656). An example of tertiary prevention initiated by the OT practitioner could be the intervention of a homebound elder who is experiencing limitations because of the pain of arthritis. The COTA would provide education about self-care activities such as joint protection and energy conservation to prevent further deterioration of arthritic joints. In addition, joint mobility can be facilitated through regular participation in a hobby within the elder's range of tolerance. Performing energy conservation activities also may assist the elder in feeling in control of his or her daily routine. Control of pain and implementation of environmental adaptations and work simplification could assist the elder and encourage greater involvement in meaningful occupations and engagement with others.

Tertiary Prevention

Tertiary prevention seeks to reduce the impact of established disease by eliminating or reducing disability; minimizing suffering; and maximizing potential years of quality life. In epidemiological terms, tertiary prevention aims to reduce the number and/or impact of complications. This is the task of therapy and rehabilitation.

Strategies for tertiary prevention include screening of patients with diabetes for diabetic retinopathy to prevent progression to blindness through prompt treatment; prevention of opportunistic infections in HIV infection; provision of prostheses and medical devices to enable persons to take part in social life; follow-up of chronically ill patients to ensure adherence to medication regimen, monitor changes, and assisting them in maintaining independence in daily life; and rehabilitation of stroke patients to restore functions, such as through physiotherapy, and prevent recurrence or further complications through appropriate medication.

The taxonomy of prevention provided here is based on Beaglehole et al. (1993) and Last (2001). A clear distinction between different levels is, however, often difficult to determine as this may vary according to the specific aims of the preventive measures. For example, dietary recommendations on saturated fat intake may be viewed as primary prevention of atherosclerosis. They can also be seen as secondary prevention if targeted at reducing the risk of CHD in patients with subclinical atherosclerosis. Likewise, tertiary prevention is often difficult to separate from treatment although several authors refer to the treatment of, for example, symptomatic cancer or surgical interventions for acute conditions such as appendicitis as tertiary prevention because these interventions seek to prevent recurrence of disease and, ultimately, reduce case fatality. Also, the taxonomy may vary according to the discipline that defines the different levels, for example, public health or clinical medicine. The distinction between primordial prevention (health promotion) and primary prevention is often not clear-cut mainly because contents and strategies frequently overlap. However, as Last (1995) has pointed out, the differences in opinions as to the precise boundaries between the various levels are semantic rather than substantive.

Tertiary Prevention

Tertiary prevention typically refers to a reduction in morbidity, complications, or mortality related to an acute or chronic disease that has recently been diagnosed and partially or entirely treated (Figs. 10-8). For HNSCC, this commonly includes reducing recurrence, second primary, metastasis, speech and swallowing dysfunction, dental and chewing problems, xerostomia and mucositis, cosmetic deformity, and other problems common in head and neck cancer patients (Table 10-7). Studies assessing the many problems along with disease-specific and overall quality of life are important to understand during and after treatment for head and neck cancer.285,286

Tertiary Prevention Interventions

Tertiary prevention interventions are those that prevent complications from STIs, such as infertility and adverse pregnancy outcomes (e.g., mother to child HIV transmission). The increase in regular screening and treatment of girls for chlamydia, for example, has been shown to reduce the incidence of pelvic inflammatory disease, which can lead to better pregnancy outcomes. STI treatment among pregnant teenagers is also crucial, whether for syphilis, trichomonas, or HIV. The use of antiretroviral drugs during pregnancy, labor, and delivery in women with HIV, has been shown to reduce the incidence of maternal-child HIV to less than 2% worldwide. Early diagnosis and treatment of HPV is also thought to reduce the incidence of cervical cancers.