Principles of Ambulatory Medicine, 7th Edition

Chapter 14

Integrating Prevention into Ambulatory Practice

Gregory P. Prokopowicz

David E. Kern

Prevention is a central part of patient care (1). Medical organizations, government agencies, insurance companies, and patients themselves expect practitioners to offer preventive services (2,3). Practitioners are in an important position to help reduce the burden of disease that affects society and its members. Evidence suggests that a health practitioner's advice can beneficially influence patient behavior (4,5). Increasingly, practitioners are being trained to interpret risks to health, to effectively communicate this information to patients, and to assist patients in desired behavior changes.

Three characteristics distinguish preventive from curative care:

1. Preventive care aims to protect health prospectively. In contrast to treatment, which tries to return a patient to a previous state of health, prevention attempts to maintain an existing state of health. This is true even for a chronically ill patient, for whom prevention might mean maintaining a limited functional status at home rather being admitted to a hospital or nursing home for a preventable worsening of illness.
2. The practitioner, not the patient, usually initiates preventive care. Although patients increasingly request preventive services, more often it is the practitioner who is aware of the need for such interventions.
3. In preventive care, the practitioner must be more certain that an intervention is effective than in the care of established disease or symptomatic conditions. Uncertainty is inherent in medicine. When ill patients seek treatment, the practitioner often must make a best guess regarding treatment. In prevention, however, patients are usually healthy and will remain so in the proximate future regardless of whether they undertake preventive measures. Consequently, there is an ethical obligation for the practitioner to have a high degree of certainty that suggested preventive interventions are likely to result in more good than harm (6).

Several considerations underlie the importance of prevention in routine office practice. First, approximately 50% of mortality from the 10 leading causes of death in the United States can be traced to alterable behavior (life-style) (7). Second, early detection and treatment of a number of common disorders, such as cervical carcinoma in situ and hypertension, effectively reduce mortality and morbidity from these conditions. Third, although infectious diseases have, to a large extent, been controlled in developed countries by public health measures such as immunization, outbreaks of pneumococcal disease continue to occur, and influenza remains a major preventable cause of death, especially among the elderly and immunocompromised (8,9). Fourth, the value of a comprehensive approach to prevention is suggested by the improvement in heath care outcomes attributable to prenatal care (10,11) and comprehensive geriatric assessment (12, 13, 14, 15).

FIGURE 14.1. Primary, secondary, and tertiary prevention in the spectrum of a disease (see text for definitions).

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Terminology

Prevention can be divided into three stages according to the timing of the intervention (Fig. 14.1). Primary prevention occurs before the start of the disease process. For example, smoking cessation decreases the likelihood that a patient will develop coronary artery disease or lung cancer, barrier contraception or abstinence prevents the development of cervical dysplasia, and immunization prevents various infectious diseases. Secondary prevention detects early disease before it has become clinically apparent. Breast, cervical, and colon cancer screening to identify and remove occult malignancies, and thereby to improve outcome, represents secondary prevention. Tertiary prevention seeks to stop further complications after a disease has become clinically evident. Treatment after myocardial infarction with aspirin, beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and statins represents tertiary prevention.

Although conceptually useful, the distinctions between primary, secondary, and tertiary prevention can become blurred in clinical practice. The early detection and treatment of asymptomatic hypertension, for example, would be considered tertiary prevention if one considers hypertension a disease and considers congestive heart failure, stroke, and renal failure complications of that disease. On the other hand, hypertension can be considered a risk factor for congestive heart failure, stroke, and renal failure, so that detection and treatment of hypertension to prevent these diseases from occurring can be considered primary prevention. Also, the terminology is not always used consistently. In the cardiology literature, for example, secondary prevention is commonly used to refer to the prevention of complications after the occurrence of a clinical event (such as myocardial infarction); this would be considered tertiary prevention using the conceptualization described here.

Several other terms are relevant to the practice of prevention. Screening is the process of identifying patients with unrecognized diseases or risk factors by the application of examinations, tests, or other procedures. A positive test is usually not diagnostic but requires further testing. Mass screening is screening applied to a large group, and multiphasic screening is simultaneous screening for various diseases, such as blood pressure and cholesterol measurement done at health fairs. Case finding occurs in a practitioner's practice when the clinician screens for disease unrelated to the symptom for which the patient has come.

Evaluating Preventive Measures for Use in Ambulatory Practice

The first step in integrating preventive care into office practice is deciding which measures to offer patients routinely. In deciding which measures to recommend, one should consider the burden of suffering attributable to each preventable condition, in terms of its prevalence and severity; the efficacy, cost, and safety of available screening tests; the efficacy and complications of treatment; and the effectiveness of each measure in routine office practice (Table 14.1). Recommendations that are periodically published by organizations such as the U.S. Preventive Services Task Force (USPSTF), Canadian Task Force on Preventive Health Care (CTF), the American Cancer Society, the American College of Physicians, the American Medical Association, the Centers for Disease Control and Prevention, and others can be consulted. For some measures, however, the recommendations are conflicting. The reports of the USPSTF and the CTF are firmly grounded in clinical epidemiology and provide the most scientific and least biased framework to date for evaluating which preventive health measures should be included in routine care (see http://www.hopkinsbayview.org/PAMreferences).

In evaluating a given measure, it is important to be aware of certain terms, concepts, pitfalls, and special considerations. The termssensitivity, specificity, prevalence, and predictive value, which help define the value of a screening test, are defined in Chapter 2. Efficacydescribes how well a test or maneuver performs under ideal circumstances. Effectiveness describes how well a test or maneuver performs under real-world circumstances. The effectiveness of a test or maneuver is usually somewhat less

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than its efficacy. Efficiency describes how well the test or maneuver optimizes the use of limited resources. A risk factor is anything that, if present, increases the likelihood of disease. The proportion of a specific disease that can be accounted for by a risk factor is called theattributable risk.

TABLE 14.1 Questions to Ask in Evaluating a Recommended Preventive Measure

What is the burden of suffering attributable to the targeted condition? What is the prevalence and/or incidence of the condition? What is the size of the attributable morbidity? What is the mortality rate? Do efficacious screening tests exist? Do they have acceptable sensitivity, specificity, and predictive value?a Are they reliable?a Are they practical and reasonably priced? Are the side effects of screening acceptable? Is preventive intervention efficacious in research settings? Is the intervention efficacious in study groups? Are compliance levels in study situations acceptable? Are side effects acceptable? Is intervention in the asymptomatic stage more beneficial than intervention after onset of symptoms? Would use of the measure be effective in routine office practice? Have suitable field trials been conducted? Is the measure effective in reducing morbidity and mortality in nonstudy situations? Are the compliance levels in nonstudy situations acceptable? Are side effects in nonstudy situations acceptable? What are the reliability, sensitivity, specificity, and predictive value of screening tests in one's own setting?a Is the measure cost-effective? aSee Chapter 2 for a discussion of reliability, sensitivity, specificity, and predictive value.

Lead time (Fig. 14.1) is the period between the early detection of disease and its usual time of diagnosis. In the evaluation of the efficacy of early detection and treatment, lead time must be subtracted from overall survival time in screened patients to avoid lead time bias. Otherwise, early detection might appear to increase survival time, when in reality it is only increasing the duration of patients’ awareness of their disease. Numerous cancer screening procedures have been thought to improve survival until lead time was addressed (16). Length bias(also called length-time bias, or length-biased sampling) occurs because tumors progress at different rates in different individuals. Screening tests preferentially find slow-growing tumors with long presymptomatic stages and better prognoses, but may miss fast-growing cancers with short presymptomatic stages, which can progress to become clinically apparent between screening intervals. Thus, survival may be better for patients detected by screening because of the characteristics of their tumors (less aggressive, lower grade), while overall mortality in screened and unscreened populations remains identical. A related concept is pseudodisease. This refers to indolent disease that would not have become clinically apparent during the lifetime of the subject had they not undergone screening, for example, a slow-growing prostate cancer in an elderly man. Selection bias occurs when patients undergoing a preventive measure differ from those with whom they are compared in a manner that affects the likelihood of their developing disease or affects the natural history of their disease. Volunteers, for example, may have more healthful lifestyles than those who do not volunteer. It is because of these biases that randomized controlled trials are important in evaluating preventive interventions.

The process of screening itself can cause morbidity. The test itself may carry a risk of complications (e.g., perforation from colonoscopy). The test may label some people as having a disease when they are in fact healthy (false positives), thereby causing anxiety or other suffering in the absence of disease. False positives refer to the identification of disease that is entirely absent, or to the identification of disease that is clinically inconsequential to the patient (pseudodisease) (17). If the disease is rare, or if the screening test does not have a high specificity, false-positive results may constitute a large fraction of all positive test results (see Chapter 2). For this reason, positive screening tests are usually followed by more specific diagnostic tests, and these may carry additional risks. On the other hand, a screening test with a low sensitivity (see Chapter 2) will inappropriately label some diseased patients as healthy (false negatives); this may induce them not to seek care even when they become symptomatic.

The advent of genetic testing and of highly sensitive imaging modalities (e.g., multislice spiral computerized tomography [CT]) has the potential to generate findings that are difficult to interpret for patient and practitioner alike (18, 19, 20). Direct-to-consumer marketing of such tests has raised additional concerns (21,22). The identification of disease or pathophysiologic abnormality in an otherwise healthy person can lead to adverse consequences from the labeling effect (23, 24, 25). For example, one study showed that absenteeism from work increased after workers were found to be hypertensive (24). Additionally, there may be implications for the patient with respect to insurance or employment. Practitioners can minimize such problems by choosing screening tests judiciously and by explaining risks and benefits to the patient, including the need for confirmatory testing and followup.

Caution should be used in adopting recommendations or guidelines that are based on demonstrations of efficacy in limited clinical trials. This is especially important with new technologies, where equipment and expertise may vary widely between institutions. For example, CT of the colon (virtual colonoscopy) has been variously reported to have a sensitivity of 59% and 90% (26). This discrepancy

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is probably a result of differences in equipment, protocols, and operator experience. As a result, the relevance of these data for the community practitioner considering CT colonography for his or her patient is questionable. The rise of freestanding radiology centers that advertise directly to the public may exacerbate the problem by increasing demand for unproven technologies (27).

Despite these precautions, there is sufficient evidence to support the integration of a number of primary and secondary preventive measures into office practice. Failure to do so reflects an inadequacy in the provision of primary care.

Components of Preventive Care

General Examination and Baseline Data

Most practitioners perform a baseline general examination (history, physical, and selected laboratory tests) for some or all of their ambulatory patients. In addition, many practitioners repeat all or part of this examination on a periodic basis, in the form of an annual checkup. In contrast to the provision of selected preventive care measures discussed below, no firm scientific evidence links most of the general examination to reductions in morbidity and mortality (3). The question of whether, and how often, to perform a general physical examination remains a topic of debate. Most patients still expect annual examinations (28), however, and many clinicians find that periodic visits enhance the doctor–patient relationship and permit updating of the medical, social, and family history. Furthermore, periodic general examinations are sometimes required for people in high-risk occupations (e.g., airline pilots).

Provision of Selected Measures for Asymptomatic Patients (Primary and Secondary Preventive Care)

It is generally recommended that practitioners offer asymptomatic patients certain preventive care measures, selected on the basis of their likely benefits versus harm (see above and Table 14.1). Table 14.2 summarizes the preventive measures that are often considered for inclusion in the care of asymptomatic nonpregnant adults. For each preventive measure, the table provides the following information:

1. The patient populationto which the measure should be applied (age, sex, risk status);
2. Recommended time intervalbetween preventive interventions;
3. Year of the recommendation;
4. Strength of the recommendationfor including or excluding the preventive measure in the care of asymptomatic patients, classified using the rating systems developed by the U.S. Preventive Services Task Force (USPSTF) and the Canadian Task Force on Periodic Health Examination (CTF).

The USPSTF rating system, which was revised in 2001 (29), assigns a grade (A through D, or I) to each preventive intervention as follows:

Grade Definition

1. The USPSTF strongly recommends that clinicians routinely provide the service to eligible patients. (The USPSTF found good evidence that the service improves important health outcomes and concludes that benefits substantially outweigh harms.)
2. The USPSTF recommends that clinicians routinely provide the service to eligible patients. (The USPSTF found at least fair evidence that the service improves important health outcomes and concludes that benefits outweigh harms.)
3. The USPSTF makes no recommendation for or against routine provision of the service. (The USPSTF found at least fair evidence that the service can improve health outcomes but concludes that the balance of the benefits and harms is too close to justify a general recommendation.)
4. The USPSTF recommends against routinely providing the service to asymptomatic patients. (The USPSTF found at least fair evidence that the service is ineffective or that harms outweigh benefits.)
5. The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing the service. (Evidence that the service is effective is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.)

The CTF uses the following rating system, revised in 2003 (30), for its recommendations:

Grade Definition

1. The CTF concludes that there is goodevidence to recommend the clinical preventive action.
2. The CTF concludes that there is fairevidence to recommend the clinical preventive action.
3. The CTF concludes that the existing evidence is conflictingand does not allow making a recommendation for or against use of the clinical preventive action; however, other factors may influence decision making.
4. The CTF concludes that there is fairevidence to recommend against the clinical preventive action.
5. The CTF concludes that there is goodevidence to recommend against the clinical preventive action.
6. The CTF concludes that there is insufficientevidence (in quantity and/or quality) to make a recommendation; however, other factors may influence decision making.

To determine the appropriate letter grade, both task forces assess the quality of evidence and the magnitude

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of benefit. The quality of evidence is based on the internal validity of each study, and is rated as good, fair, or poor. This rating is based on the number, quality, and consistency of the studies, whether important health outcomes were studied, and whether the results are generalizable to routine practice. Studies are assessed according to their susceptibility to bias using a hierarchy of research designs. Levels of evidence are assigned using the following hierarchy:

TABLE 14.2 Preventive Measures to Consider in the Care of Asymptomatic Nonpregnant Adults

Preventive Measure Patient Population (Sex, Age [Years], Risk Status) Time Interval Year of Recommendation Strength of Recommendationa,b Chapter(s) to See for Details Good Evidence to Include Aspirin for primary prevention of cardiovascular events, discussion of benefits/risksc M, F at high riskc 5 y 2002a A 57, 62, 91 Blood pressure All M, F ≥18a or 21b 1–2 y 2003a, 1994b Aa, Bb 67 Breast cancer screening Mammography, with (preferable) or without clinical breast examination by health care practitioner All F 50–69d 1–2 y 2002a, 1998b Ba,e, Ab,e 105 Cervical cytology (Papanicolaou [Pap] test) All F who have a uterus, onset of sexual activity, or age 18b–21a(whichever comes earlier) to age 65a–69b(if previous 2 Pap smears are normal) 1 y × 2, then 3 yf 2003a, 1994b Aa, Bb 104 Chlamydia screening Fg at high risk Discretionary, recommend at time of Pap smearsh 2001a, 1996b Aa, Bb 37, 102 Cholesterol, nonfasting total cholesterol (TC) and HDL cholesterol levels with further evaluation and treatment of those found to have high TC or low HDLi All M ≥35; all F ≥45 5 y 2001a Aa 82 Colorectal cancer screening: fecal occult blood testing (FOBT), sigmoidoscopy, or colonoscopy All M, F ≥50, normal risk 1 y (FOBT), 5 y (sigmoidoscopy), 10 y (colonoscopy)j 2002a, 2001b Aa,b 45 Folate prophylaxis F, previously affected pregnancy (neural tube deficit) or planning pregnancy Beginning 1–3 mo before conception through 1st trimester 1996a, 1994b Aa,b 100 Gonococcal culture F at high riskkonlya or M, Fb Discretionaryh 2005a, 1994b Ba, Ab 37, 102 Hepatitis B vaccination All young adults not previously immunized and high-risk M, F of all agesl Three doses, at 0, 1, and 6 mo 1996a Aa 18, 39, 47 HIV antibody testing M, Fm at high risk Discretionary 2005a, 1994b Aa,b 39 Influenza vaccination All M, F ≥65; high-risk M, F of all agesn; health care providers for high-risk patients 1 y 1996a, 1994b Aa, Bb 18 Measles, mumps, rubella (MMR) vaccination (live) All M and nonpregnant F born after 1956 who lack evidence of immunity to measleso Once, or 2 doses ≥1 month aparto 1996a Aa 18 Pneumococcal vaccination M, Fp at high risk (see below for others) Once, consider repeat dose at 5 y 1996a, 1998b Ba, Ab 18 Smoking/tobacco use, counseling All M, F 1–5 y 2003a, 1994b Aa,b 27 Syphilis (serology), screening M, Fq at high risk Discretionary 2004a Aa 37, 39,102 Tetanus/diphtheria vaccination All M, F 10 y or once after age 50 y (boosters); primary series at 0, 2, and 6–14 mo if not previously immunized 1996a Aa 18 Tuberculin skin test M, Fr at high risk Discretionary 1996a, 1994b Aa,b 34, 39 Travel to developing countries: immunization, prophylactic medications, counseling regarding preventive health practices M, F at risk Varies Ah 41 Fair Evidence to Include Abdominal aortic aneurysm, screening ultrasonography M 65–75 who have ever smoked Once 2005a Ba 94 Alcohol use, screening, with counseling of patients with problem drinking and counseling/referral of alcohol-dependent patients All M, F Discretionary 2004a, 1994b Ba,b 28 Birth control counseling to reduce unwanted pregnancies All sexually active M, F of childbearing age, especially adolescents Discretionary 1996a, 1994b Ba,b 100 Bone densitometry All F >65; F >60a or postmenopausal Fb at high riskss Discretionary, >2 y 2002a, 2004b Ba, Bb 103 Breast cancer screening Mammography with or without clinical breast examination by health care practitioner All F 40–49 1–2 y 2002a, 2001b Ba,e, Cb 105 Genetic counseling with or without BRCA gene testing Adult F with strong family history of breast cancer once 2005a Ba 17, 105 Cholesterol, nonfasting TC and HDL cholesterol levels, with further evaluation and treatment of those found to be have high TC or low HDLi M 20–35, F 20–45 with risk factorst M 20–35, F 20–45 without risk factorst 5 y 5 y 2001a 2001a Ba Ca 82 Colorectal cancer screening: sigmoidoscopyj All M, F ≥50, normal risk 3–10 y 2001b Bb 45 Depression, screening All M, F Discretionary 2002a, 2005b Ba,b 24, 26 Diabetes mellitus, screening (e.g., with fasting plasma glucose) M, F with hypertension or hyperlipidemia Discretionary 2003a, 2005b Ba,b 79 Diet: routine behavioral counseling All M, F Ongoing 2003a, 1994b Ia, Bb 15, 82 Exercise, inquiry and counselingu All M, F Discretionary 2002a, 1994b Ia, Bab 12, 16,63, 83,103 Fall prevention All M, F admitted to long-term care facilities Discretionary 2005b Bb 12 Hearing impairment, screening All M, F >65 Discretionary 1996a, 1994b Ba,b 110 Obesity: screening (weight and height, BMI calculation) All M, Fv Periodic 2003a, 1999b Ba, Cb Pneumococcal vaccination All M, F ≥65 (see above for others) Once 1996a, 1998b Ba, Cb 18 Rubella vaccination (or MMR) or rubella antibody screening and vaccination of those susceptible All nonpregnant F of childbearing age without documentation of previous rubella vaccination Once, or 2 doses ≥1 mo apartw 1996a, 1994b Ba,b 18 Seatbelt use, counseling All M, F Discretionary 1996a, 1994b Ba,b — Skin inspection to detect skin cancer M, Fx at high risk Discretionary 2001a, 1994b Ia, B and Cb 114 Varicella vaccination Susceptible adolescents and adults 2 doses given 4–8 wk apart 2001b Bb 18 Visual acuity testing All M, F >65 Discretionary 1994, 1995b Bb 107 Insufficient Evidence to Include or Exclude Abdominal aortic aneurysm, screening ultrasonography M 65–75 who have never smokeda, asymptomatic individualsb Once 2005a, 1994b Ca,b 94 Aspirin therapy for the primary prevention of cardiovascular disease All M 40–84 All F 50–84 Not applicable 1996a, 1994b 1996a, 1994b Ca,b Ca,b 57, 62, 91 Breast self-examination, teaching/encouraging All F ≥20 1 mo 2001a,b Ia, Db 105 Carotid artery stenosis, screening Auscultation or ultrasonography All M, F >40–60 or at high risk for atherosclerotic cardiovascular disease Discretionary Discretionary 1996a, 1994,b1996a Ia, Db Ca 91 Clinical breast examination by health care practitioner All F ≥40 1–2 y 2002a Ia 105 Colorectal cancer, screening: CT colonography (virtual colonoscopy), colonoscopyj All M, F ≥50 5–10 y 1996a, 2001b Ia, Cb 45 Dementia (cognitive impairment) screening All M, F ≥65–75 Discretionary 2003a, 2001b Ia, Cb 26 Dental hygiene, primary care practitioner screening (for periodontal disease) or counseling (regarding brushing, flossing, fluoride, diet, and regular dental visits)y All M, F Discretionary 1996a, 1994b, 1995b Ca,b 112 Diabetes mellitus, screening (e.g., with fasting plasma glucose) All M, F Discretionary 2003a, 1994b Ia, Db 79 Domestic violence, screening All F and elderly Discretionary 2004a, 2003b Ia,b 28 Driving while impaired by alcohol or drugs, counseling All M, F Discretionary 1996a, 1994b Ca,b 28, 29 Drug abuse, screening All M, F Discretionary 1996a Ca 29 Coronary artery disease: Resting ECG, exercise treadmill, electron-beam CT scanning M, F at high risk Discretionary 2004a Ia 16, 62 Falls prevention, counselingz All M, F ≥70–75 Discretionary 1996a, 1994b Ca,b 12 Firearms at home, counselingaa All M, F Discretionary 1996a, 1994b Ca,b — Glaucoma: tonometry or other methods M, F ≥65 Discretionary 2005a, 1995b Ia, Cb 108 Gonococcal culture M at high-riskk Discretionary 2005a Ia 37 Helmets, bicycle or motorcycle, counselingbb All M, F Discretionary 1996a, 1994b Ca,b — Homocysteine, screening with fasting or postmethionine load plasma total homocysteine to detect and treat patients with high levels M ≥35, F ≥45 at normal or high risk for coronary artery disease Once 2000b Cb 62 Lung cancer screening: chest CT scanning All M, F 1 y 2004a, 2003b Ia,b 61 Annual chest radiograph Ia, Db Sputum cytology Ia Obesity: counseling All M, F Discretionary 2003a, 1994 and 1999b Ia, Cb 83 Oral cancer screening Smoking M, F ≥50 Discretionary 2004a, 1999b Ia, Cb 112 Prostate cancer: All M ≥40–50 1–2 y 2002a, 1994b Prostate-specific antigen (PSA) Ia, Db 53 Digital rectal examination Ia, Cb 53 Sexually transmitted diseases, counseling All sexually active M, F Discretionary 1996a Ca 37, 39 Thyroid function tests (TSH) or clinical examination to diagnose occult hyper- and hypothyroidism All F, postmenopausal Discretionary 2004a, 1994b Ia, Cb 80 Fair to Good Evidence to Exclude Bacteriuria M, nonpregnant F Discretionary 2004a D 36 Bladder cancer M, F ≥50 Discretionary 2004a Da 49 Breast cancer chemoprophylaxis All F, low to normal risk Ongoing 2002a, 2001b Da,b 105 Coronary artery disease: M, F at low risk Discretionary 2004a Da 16, 62 Resting ECG, exercise treadmill ECG, electron-beam CT scanning Gonococcal culture Sexually active M, F at low risk of infection Discretionary 2005a, 1994b Da,b 37, 102 Herpes simplex screening Asymptomatic adults, adolescents Discretionary 2005 Da 37 Hormone replacement therapy Perimenopausal and postmenopausal women Ongoing 2005a, 2004b Da,b 103, 106 Ovarian cancer screening (pelvic exam, cancer antigen [CA]-125 level or transvaginal ultrasonography) All F Discretionary 2004a, 1994b Da,b 104 Peripheral arterial disease screening (ankle brachial index) Asymptomatic adults Discretionary 2005 Da 94 Prostate cancer screening 53 Transrectal ultrasonography Db BMI, body mass index; CT, computerized tomography; ECG, electrocardiogram; HDL, high-density lipoprotein; HIV, human immunodeficiency virus. This table is organized into four major categories, based on the strength of the recommendation for including or excluding a preventive measure, as rated by the U.S. Preventive Services Task Force (USPSTF) and the Canadian Task Force on the Periodic Health Examination (CTF) (see text for explanation of ratings). When ratings differ between the USPSTF and CTF, a preventive measure is placed in one of the four categories based on its highest rating. Preventive measures are listed in alphabetical order under each category. aRated by the USPSTF. See text for explanation of ratings. bRated by the CTF. See text for explanation of ratings. cHigh risk includes a combination of male sex, postmenopausal state, cigarette smoking, diabetes, hypertension, hypercholesterolemia, family history resulting in a 5-year risk of a coronary heart disease (CHD) event of> 3–5%. Reduction in CHD events have to be weighed against increased risk of hemorrhagic strokes and major gastrointestinal (GI) bleeding events. Benefit begins to outweigh risk at a CHD risk of 3%, and is clearer at a risk of 5%. However, a reduction in total mortality has not been demonstrated. Quantitatively, the risks are low. At a 5-year 5% risk, an individual would have an absolute risk reduction of 0.6% to 2.0% in myocardial infarction over 5 years. At any risk, an individual would have a 0% to 0.2% increase in hemorrhagic stroke and a 0.2% to 0.4% increase in major GI bleed (52). Risk calculators for CHD risk are available from the National Cholesterol Education Program (http://www.nhlbi.nih.gov/guidelines/cholesterol/index.htm ) and through Epocrates (http://www2.epocrates.com/index.html ). Five-year risks are about half of the 10-year risks derived from the calculators. dA meta-analysis by the USPSTF has determined that screening mammography is beneficial beyond the age of 65 years (53), and the USPSTF gives a B recommendations for mammography screening in all women age 40 years and older. eA recent meta-analysis has called into question the efficiency of screening mammography (54,55) and precipitated controversy (56,57). The USPSTF subsequently issued recommendations, downgrading the strength of their recommendation from A to B after critiquing the above meta-analysis and extending their recommendation to women 40–49 years of age. The USPSTF does note that the evidence is strongest for women 50–69 years of age and weaker for women 40–49 years of age. The CTF has not yet responded to the above meta-analysis. fWhen screening is initiated, it is often recommended that the first two to three smears be obtained 1 y apart, as the sensitivity of a single Pap smear may be only 60%–80%. Although there is little additional benefit to routine screening more frequently than every 3 y in average-risk patients, risk factors such as early onset of sexual intercourse, history of multiple sexual partners, and low socioeconomic status may warrant more frequent testing. More frequent intervals are also recommended for HIV-infected patients (twice in the first year, annually thereafter). gHigh-risk groups include sexually active females ≤25 years of age; new sexual partner; multiple sexual partners; history of sexually transmitted disease; cervical friability, ectopy, or mucopurulent discharge; unmarried status; inconsistent use of barrier contraceptives; and other settings where prevalence is known to be high. hRated or recommended by the authors on the basis of USPSTF, CTF, or other reports. iBecause of biologic variation and measurement error, two blood tests are often recommended to provide a more accurate measure for classification of risk. When total cholesterol concentration is >200 mg/dL (>5.2 mmol/L) or HDL is low (< 40 mg/L), a fasting determination of total cholesterol, triglyceride, and HDL cholesterol levels with calculation of the low-density lipoprotein (LDL) cholesterol level is recommended to more precisely determine risk and direct treatment (see Chapter 82). The National Cholesterol Education Program recommends a fasting lipid profile every 5 years in all adults ≥20 (see Chapter 82). jThe USPSTF recommends use of either FOBT, sigmoidoscopy, or colonoscopy, and does not provide separate grades for the three tests. In contrast, the CTF rates FOBT as grade A, sigmoidoscopy as grade B, and colonoscopy as grade C. With respect to screening intervals, only the recommendation for yearly FOBT is backed by direct clinical trial evidence. Sigmoidoscopy and colonoscopy intervals are recommendations based on indirect evidence (e.g., natural history studies of polyp growth). The USPSTF assigns a grade of I to CT colonography (virtual colonoscopy). The CTF reports fair (B) evidence to support a recommendation for routine colonoscopy in patients with familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC). A strong family history of colon cancer (e.g., >2 first-degree relatives with colorectal cancer) will likely influence the patient and clinician toward colonoscopy as a screening strategy. It is a standard of care for patients with inflammatory colon disease (ulcerative colitis or Crohn disease), usually at intervals of 1 to 2 years. kHigh-risk groups include history of previous gonorrhea infection, other sexually transmitted infections, new or multiple sexual partners, inconsistent condom use, sex work, and drug usea; or persons younger than age 30 years with>2 sexual partners, sexual contacts of persons known to have a sexually transmitted disease, age ≤16 years at first intercourse, and prostitutesb. lHigh-risk groups include homosexually active men; injection drug users and their sex partners; persons who have a history of sexual activity with multiple partners in the previous 6 months or who have recently acquired another sexually transmitted disease; international travelers to countries where hepatitis B virus is of high or intermediate endemicity; and persons in health-related jobs with frequent exposure to blood or blood products. mHigh-risk groups include men who have had sex with men after 1975; men and women having unprotected sex with multiple partners; past or present injection drug users; men and women who exchange sex for money or drugs or who have sex partners who do; individuals whose past or present sex partners were HIV-infected, bisexual, or injection drug users; persons being treated for sexually transmitted diseases (STDs); and persons with a history of blood transfusion between 1978 and 1985. nHigh-risk groups include residents of chronic care facilities and other institutions and persons with chronic cardiopulmonary disorders, metabolic diseases (including diabetes mellitus), hemoglobinopathies, immunosuppression, or renal dysfunction. oEvidence of immunity can include receipt of two doses of live vaccine after first birthday, laboratory evidence of immunity, or practitioner-diagnosed disease. Contraindicated in immunosuppressed and pregnant patients. Women should be advised not to become pregnant for 1–3 months after vaccination. Patients vaccinated before 1967 are likely to have received inactivated vaccine or have been vaccinated before the age of 12 months. Two doses may be required ≥1 months apart to ensure long-term efficacy. One dose is approximately 95% effective in achieving seroconversion. pHigh-risk groups include patients with sickle cell disease; patients postsplenectomy; institutionalized patients age ≥50 years; people in epidemic or endemic settings. Antibody levels may fall after 5 years, and revaccination at 5 years is recommended in certain populations (see Chapter 18). qHigh-risk groups include men who have sex with men and who engage in high-risk sexual behavior, commercial sex workers, persons who exchange sex for drugs, and those in adult correctional facilities. rHigh-risk groups include household/close contacts of patients with tuberculosis (e.g., staff members of tuberculosis clinics, homeless shelters); recent immigrants from countries with high tuberculosis prevalence; migrant workers and other populations with high prevalence of tuberculosis; residents of nursing homes, correctional institutions, and homeless shelters; persons with certain underlying medical disorders (e.g., HIV infection); alcoholics; and injection drug users. sRisk factors include white or Asian ethnicity, history of fracture, family history of osteoporotic fracture, history of falls, low physical activity, smoking, excessive alcohol or caffeine use, low calcium or vitamin D intake, use of medications with osteoporosis as a side effect (e.g., corticosteroids). tRisk factors include hypertension; diabetes; cigarette smoking; HDL <40 mg/dL (subtract one risk factor if HDL is ≥60 mg/dL); age ≤40 years (men) or ≤55 years (women); family history of coronary artery disease (before age 55 years in a male first-degree relative or before age 65 years in a female first-degree relative). uEfficacy of counseling by primary care practitioner is unproven. There is good (A) to fair (B) evidence, based on II-1– and II-2–level evidence, to suggest that regular physical activity can prevent all-cause mortality from coronary artery disease, hypertension, diabetes mellitus, obesity, and other diseases. Physical activity is also associated with improvements in self-esteem, stress management, lipoprotein levels, and physical fitness. vIn 1999, the CTF gave a B rating for measuring weight, height, and BMI in obese patients with obesity-related diseases: diabetes mellitus, hypertension, coronary artery disease, hyperlipidemia, and obstructive sleep apnea. wFor prevention of congenital rubella. Contraindicated in immunosuppressed and pregnant patients. Women should be advised not to become pregnant for 1–3 months after vaccination. One dose is approximately 95% effective in achieving seroconversion. xHigh-risk groups are defined as persons at high risk for cancer of skin, such as outdoor workers, fair-skinned men and women, those in contact with polycyclic aromatic hydrocarbons, those with atypical or>50 moles, and those with family history of melanoma. yEfficacy of primary care practitioner screening or counseling to change behaviors has not been adequately evaluated. There is fair (B) to good (A) evidence, however, based on levels I, II-1, and II-2 evidence to support water fluoridation, tooth brushing with fluoride-containing toothpaste, and professionally applied topical fluorides (for high-risk patients) to prevent caries and to support regular brushing and flossing, professional scaling and prophylaxis, and use of chlorhexidine or phenolic antiseptic (e.g., Listerine) oral rinses as an adjunct to tooth cleaning to prevent gingivitis/periodontal disease. zEfficacy of practitioner counseling to patients to address risk factors for falls is unproven. There is good (A) to fair (B) evidence, based on I-, II-1–, and II-2–level evidence, to support multidisciplinary assessment and intervention to prevent falls in the elderly. aaEfficacy of practitioner counseling is unproven. There is fair (B) evidence, based on levels II-2, II-3, and III evidence, to support removal of guns from or safe storage of guns in the home (USPSTF). bbEfficacy of practitioner counseling is unproven. There is good (A) evidence, based on levels II-2 and II-3 evidence, to support wearing approved helmets.

Level Definition

• I.Evidence obtained from at least one properly randomized controlled trial.
• II-1.Evidence obtained from well-designed controlled trials without randomization.
• II-2.Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.
• II-3.Evidence obtained from comparison between times or places (CTF) or from multiple time series (USPSTF) with or without the intervention. Dramatic results in uncontrolled experiments (such as the results of the introduction of penicillin treatment in the 1940s) could also be regarded as this type of evidence.
• III.Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

If the quality of evidence is judged to be good or fair, the magnitude of benefits and harms are then rated as “substantial,” “moderate,” “small,” or “zero/negative.” Although both bodies place special emphasis on the strength of the evidence regarding the effectiveness of preventive intervention, consideration is also given to the burden of suffering caused by the target condition and to the characteristics of the intervention (e.g., cost [31], availability, and acceptability). Most of this information is available in the publications and full text reviews that are available at the CTF and USPSTF websites (see http://www.hopkinsbayview.org/PAMreferences).

The preventive measures summarized in Table 14.2 pertain to average- and high-risk, asymptomatic, nonpregnant adults. Factors that may dictate expanded or more limited surveillance for the individual patient may not be included. Characteristics that should always be considered when planning preventive care for an individual patient include the average remaining life expectancy for a person of the patient's age, comorbidity that is likely to affect the patient's life expectancy, and the time to benefit for the preventive measure being considered. Thus, a 55-year-old male patient with inoperable lung cancer should receive influenza and pneumococcal vaccines but should probably not receive most of the other preventive care appropriate for his age and sex. On the other hand, a 50-year-old male patient who has survived an uncomplicated myocardial infarction at the age of 48 years has a reasonable life expectancy and should be offered all the preventive care appropriate for his age group. Life expectancies for elderly patients are included in Table 12.1. Another characteristic that may influence decisions about preventive care is the presence of diseases that confer increased risk. For example, in the presence of hereditary polyposis or ulcerative colitis, endoscopic screening should be encouraged because of the increased risk of colorectal cancer.

Preventive Care for Established Conditions (Tertiary Preventive Care)

Preventing complications of chronic diseases is a major part of office practice. By careful practice of tertiary prevention, practitioners may minimize or postpone the poor outcomes of diabetes mellitus, congestive heart failure, degenerative joint disease, human immunodeficiency virus (HIV) infection, and other conditions. Of course, appropriate preventive care for an established disease depends on the disease and the patient. Examples include appropriate education and monitoring of foot care and screening for retinopathy in diabetic patients, taking steps to enhance compliance and prevent rehospitalization in a poorly compliant elderly patient with congestive heart failure, prescribing aspirin, beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and statins in patients with myocardial infarction, and providing short-term counseling for a survivor of a myocardial infarction who is showing early symptoms of depression. The strategies for optimal preventive management of established conditions are discussed in their respective chapters.

Extending Prevention to the Family and the Community

Practitioners should extend preventive care beyond the individual when this is appropriate. In some instances, preventive treatment should be recommended for members of a patient's family and other close contacts. Immunoglobulin prophylaxis for the family of a patient with infectious hepatitis A and treatment of sexual contacts of patients with sexually transmitted diseases are classic examples. In other situations, the practitioner should recommend evaluation of the relatives of patients with certain chronic diseases that show a tendency to occur in families. For example, relatives of patients with familial hypercholesterolemia should have plasma lipid levels determined, and routine screening should be encouraged for at-risk relatives of patients with breast and colon cancers. For some conditions and some patients, genetic testing and counseling may be advisable (see Chapter 17).

Prevention should be extended to the community at large when a notifiable communicable disease is diagnosed in an individual patient (Table 14.3). Similarly, any

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suspected occupational disease in an individual worker should be reported to local health authorities and/or a regulatory agency, such as the Occupational Safety and Health Administration or the Environmental Protection Agency. In some states, laboratories are required to report abnormal findings of public health significance (e.g., elevated levels of heavy metals). Such reporting may be critical in protecting the health of others in the same community, work, or home environments (see Chapter 8).

TABLE 14.3 Reportable Diseases and Conditionsa

Acquired immunodeficiency syndrome (AIDS)b Meningitis, infectious Amebiasis Meningococcal diseaseb,c Animal bitesc Microsporidiosis Anthraxb,c Mumpsb Arboviral infections, including those causing encephalitis (see below) Mycobacteriosis, other than tuberculosis and leprosy Botulismb,c Occupational disease (see Chapter 8) Brucellosisb,c Pertussisb,c Campylobacter infection Pertussis vaccine adverse reactions Cancer, new cases Pesticide-related illness Chancroidb Plagueb,c Chlamydia trachomatis, genital infectionb Pneumonia in a health care worker resulting in hospitalization Cholerab,c Poliomyelitis, paralyticb,c Coccidiomycosisb Psittacosisb Cryptosporidiosisb Q feverb,c Cyclosporiasisb Rabies, human or animalb,c Dengue feverc Ricin toxinc Diphtheriab,c Rocky Mountain spotted feverb Ehrlichiosisb Human, granulocyticb Human, monocyticb Human, other or unspecified agentb Rubella (German measles)b,c Encephalitisb California serogroupb Eastern equineb Powassanb St. Louisb Western equineb West Nileb Rubella congenital syndromeb,c Enterohemorrhagic Escherichia coli (EHEC)b EHEC 0157:H7b EHEC serogrop non-0157b EHEC, not serogroupedb Salmonellosisb Epsilon toxin of Clostridium perfringensc Septicemia in newborns Giardiasisb Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) diseaseb,c Glanders (BurkholderiaorPseudomonas mallei)c Shigalike toxin producing enteric bacterial infections Gonorrheab Shigellosisb Haemophilus influenzae, invasive diseaseb,c Smallpox and other orthopoxvirus infectionsc Hantavirus Pulmonary syndromeb,c Any infectionc Staphylococcal enterotoxin Bc Harmful algal bloom-related illness Streptococcal disease, invasive Group Ab Group B Heavy metal poisoning (e.g., tests showing elevated levels of lead, mercury, arsenic, cadmium must be reported by laboratories in Maryland) Streptococcus pneumoniae, invasive disease Drug-resistant, all agesb Age <5 yb Hemolytic-uremic syndrome, postdiarrhealb Streptococcal toxic shock syndromeb Hepatitis, viral (A,b B,b C,b D, E, G, undetermined) Syphilisb Human immunodeficiency virus (HIV) infectionb Syphilis, congenitalb Isosporiasis Tetanusb Kawasaki syndrome Toxic shock syndromeb Legionellosisb,c Trichinellosisb,c Leprosy (Hansen disease)b Tuberculosisb,c and suspected tuberculosisc Leptospirosis Tularemiab,c Listeriosisb Typhoid feverb,c Lyme diseaseb Varicella (chickenpox)b Malariab Varicella deathsb Vibriosis, noncholera types Viral hemorrhagic fevers (all types)c Measles (rubeola)b,c Yellow feverb,c Yersiniosis An outbreak of disease of known or unknown etiology that may be a danger to public healthc A single case of a disease of known or unknown etiology that may be a danger to public health An unusual manifestation of a communicable disease in an individual aDetermined at the state and federal levels. Reportable to local health department. This list was developed based on information obtained from the Maryland Department of Health and Mental Hygiene and Department of the Environment and from Summary of Notifiable Diseases, United States, 2003. MMWR 2005;52:3. Reporting of nonfederally mandated diseases varies by state. bNotifiable diseases, United States (reported by state or local health departments to the Centers for Disease Control and Prevention, Atlanta, Georgia). cReportable immediately by telephone to the local health department.

These extensions of the role of the practitioner from treating individual patients to interventions at the family and community levels may raise important questions about patient confidentiality. Although practitioners are bound to protect confidentiality, some states and some courts have ruled that society's welfare occasionally outweighs the patient's right to privacy. Some states require reporting of all patients with newly diagnosed human immunodeficiency virus infection, and some protect practitioners who break confidentiality to notify exposed individuals at risk. Most courts agree that practitioners have a duty to warn individuals when patients make threats to harm them. Primary care practitioners should become acquainted with local and state rules regarding reporting.

Finally, some practices are situated to address the preventive care needs of defined populations and not just the patients who visit the practice. Examples of defined populations might be all enrollees in a managed care plan assigned to one's practice or people living in a geographic area related to one's practice. Ideally, practices should develop processes by which the health problems and preventive care needs of such defined populations are systematically identified and addressed. This approach to health care, called community-oriented primary care, combines principles of primary care medical practice, clinical epidemiology, and public health (32). Increasing computerization, health care databases, and opportunities for the linkages of databases are enhancing the feasibility of such approaches. However, limited financial support is an important current barrier to widespread implementation (33).

Putting Prevention Into Practice

Practitioner Performance

Despite sound evidence that supports the routine provision of selected preventive measures, studies show that practitioners often fail to provide them (34, 35, 36, 37, 38, 39, 40, 41). Results from the National Health Interview Survey showed that in 1998, Papanicolaou (Pap) tests had been obtained by 79% of eligible women within the previous 3 years, mammography by 67% within the prior 2 years, fecal occult blood by 35% within the preceding 2 years, and sigmoidoscopy by 37% ever (42). The Healthy People 2010 report targets a goal of 90% for Pap smears, 70% for mammography, 50% for fecal occult blood testing screening, and 50% for sigmoidoscopy (42).

Barriers to Optimal Performance

Although the American Medical Association has promoted the periodic health examination since the 1920s, only recently have both practitioners and the public come to accept the value of prevention (3). Practitioner attitudes

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toward prevention predict performance (34), and negative attitudes remain a barrier. Training of medical residents in clinical prevention may be inadequate (35,36,38,39). Although coverage of preventive services by insurance companies is improving and reimbursement is available from most managed care organizations and private insurers, confusion remains in the minds of practitioners and patients alike regarding the value of specific preventive services. The promotion of innumerable preventive measures by special interest medical groups can be overwhelming and confusing to practitioners and the public alike, because the guidelines are often short-lived, conflicting, and based on incomplete analysis and inadequate evidence. The publishing of guidelines based on clearly defined rules of evidence by the USPSTF and the CTF has helped alleviate the situation (see above and Table 14.2). However, time remains a barrier. A recent study estimated that implementation of all relevant USPSTF recommendations for a practice covering 2,500 patients would require the physician to spend 7.4 hours per working day on preventive services alone (43). Perhaps the most important barrier to providing preventive services is the failure of practitioners to organize their practices for the efficient reliable provision of selected indicated preventive services.

Improving Performance in One's Practice

It is generally agreed that preventive care must be planned carefully if it is to be offered routinely and effectively to patients in a busy office practice. First, agreed upon and feasible guidelines must be developed that outline which measures are to be offered to which patients. Second, a plan must be developed to implement the guidelines. Third, assessment of the effectiveness of implementation should be performed.

The guidelines can be made accessible to practitioners by posting them, in abbreviated form, for quick reference in each examining and consulting room (Fig. 14.2). An Interactive Preventive Services Selector that provides USPSTF guidelines for Palm or Pocket PC devices is available from the USPSTF website (http://www.198.76.191.14/ipss/ipss.htm).

Methods that may cue practitioners to provide indicated preventive care include listing “Health Maintenance” as a problem at the top of each patient's problem list (see Fig. 1.1) and having a risk profile on the front sheet or on a preventive care profile in the paper or electronic record (Fig. 14.3) in the chart of each patient. Documentation of

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preventive care is often inadequate (44). Maintenance of a preventive care flow sheet (Fig. 14.3) will help the practitioner efficiently determine which measures are due and which have already been done. Otherwise, much time may be spent trying to retrieve relevant information that has become buried in the text of the chart.

FIGURE 14.2. Sample of abbreviated preventive care standards available as wallet-size cards and posted in each examining room in the medical clinic. (Courtesy of Johns Hopkins Bayview Medical Center, Baltimore, MD.)

FIGURE 14.3. Sample preventive care profile and flow sheet. (Courtesy of Johns Hopkins Bayview Medical Center, Baltimore, MD.)

Various types of external prompts can improve clinician performance (45). Office computers can be programmed or available computer software can be used to produce preventive care reminders for each visit, which can appear in patients’ electronic patient records or can be attached to their paper charts (39,46). Nurses (40) or midlevel practitioners also can be trained to monitor and provide preventive care within the office. Audit and feedback can result in improvements in practitioner performance that can be transferred from one setting to another and persist after cessation of the intervention (36,47). Financial reimbursement in fee-for-service settings and financial incentives in managed care settings may also motivate improved practitioner performance (41,48).

Although it is desirable to schedule special time for a baseline history and physical examination for patients new to a practice, ongoing preventive care is best incorporated into routine office visits. This is so because few visits to the practitioner are purely preventive and because attendance rates are lower for preventive than for problem-based visits (49). For otherwise healthy patients who see their practitioners infrequently, however, health maintenance visits should be scheduled and appointment reminders sent to increase attendance rates.

Motivating Patients

Unfortunately, simply recommending a preventive measure to a patient is not sufficient to ensure compliance. When the preventive measure involves an unpleasant procedure (e.g., colonoscopy or pelvic examination) or requires active participation (e.g., collection and return of stool samples or the long-term taking of medication), poor compliance is likely. It is most likely to be a problem when the preventive intervention requires a major change in behavior on the part of the patient (e.g., dietary change or smoking cessation).

Motivating patients to comply with recommendations requires considerable skill on the part of the practitioner. Increasing patients’ knowledge and understanding is a necessary but often insufficient prerequisite for behavioral change. Important additional ingredients for success include the establishment of a trusting, friendly, and supportive patient–practitioner relationship (see Chapters 3 and 4); involvement of patients in planning and monitoring their own health maintenance plan (see Chapter 4); use of motivational and behavioral strategies to enhance compliance (see Chapters 4 and 27); and the promotion of healthy positive beliefs, attitudes, values, and self-perceptions in one's patients (see Chapter 4). Patients who have confidence and truly believe they can affect their health are more likely to do so than those who do not. This perceived self-efficacy or expectation for success may be the best predictor of whether patients will initiate and persist in an activity (50,51). It should be remembered that a patient's motivation to comply may be different from the practitioner's motivation in wanting them to comply. For example, patients tend to be less impressed than practitioners with long-term benefits, and more impressed with short-term benefits. Accordingly, the practitioner should stress the factors that seem to motivate the patient. Conversations related to prevention provide opportunities for patients to share their life goals with practitioners and may increase the satisfaction of both with the practitioner–patient relationship.

Printed materials may assist this process. Educational handouts can provide information on preventive care measures for patients. Easy-to-use forms for recording and monitoring their own preventive care may promote patients’ involvement in their own care, thereby prompting patients and practitioners to address recommended preventive measures.

Specific References*

For annotated General References and resources related to this chapter, visit http://www.hopkinsbayview.org/PAMreferences.

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