Am Fam Physician. 2003;68(10):2019-2022
This statement summarizes the U.S. Preventive Services Task Force (USPSTF) recommendations on screening for high blood pressure and the supporting scientific evidence.1 It updates the 1996 recommendations contained in the Guide to Clinical Preventive Services, second edition.2 Explanations of the ratings and of the strength of overall evidence are given in Tables 1 and 2, respectively. The complete information on which this statement is based, which includes a brief review of the supporting evidence, is available in “Screening for High Blood Pressure: A Review of the Evidence for the U.S. Preventive Services Task Force.” The recommendation statement and summary of the evidence can be obtained through the USPSTF Web site (http://www.uspreventiveservicestaskforce.org) and the National Guideline Clearinghouse (http://www.guideline.gov). They also are available in print through the Agency for Healthcare Research and Quality Publications Clearinghouse (telephone: 800–358–9295; e-mail:email@example.com).
This statement was first published in Am J Prev Med 2003;25:159–64.
Summary of Recommendations
The USPSTF strongly recommends that clinicians screen adults aged 18 and older for high blood pressure.A recommendation.
The USPSTF found good evidence that blood pressure measurement can identify adults at increased risk for cardiovascular disease due to high blood pressure, and good evidence that treatment of high blood pressure substantially decreases the incidence of cardiovascular disease and causes few major harms. The USPSTF concludes that the benefits of screening for and treating high blood pressure in adults substantially outweigh the harms.
The USPSTF concludes that the evidence is insufficient to recommend for or against routine screening for high blood pressure in children and adolescents to reduce the risk of cardiovascular disease.I recommendation.
The USPSTF found poor evidence that routine blood pressure measurement accurately identifies children and adolescents at increased risk for cardiovascular disease, and poor evidence to determine whether treatment of elevated blood pressure in children or adolescents decreases the incidence of cardiovascular disease. As a result, the USPSTF could not determine the balance of benefits and harms of routine screening for high blood pressure in children and adolescents.
|The USPSTF grades its recommendations according to one of five classifications (A, B, C, D, or I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms).|
|A.||The USPSTF strongly recommends that clinicians 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.|
|B.||The USPSTF recommends that clinicians 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.|
|C.||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 benefits and harms is too close to justify a general recommendation.|
|D.||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.|
|I.||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 .|
Office measurement of blood pressure is most commonly done with a sphygmomanometer. High blood pressure (i.e., hypertension) usually is defined in adults as a systolic blood pressure (SBP) of 140 mm Hg or higher, or a diastolic blood pressure (DBP) of 90 mm Hg or higher. Due to variability in individual blood pressure measurements (occurring as a result of instrument, observer, and patient factors), it is recommended that hypertension be diagnosed only after two or more elevated readings are obtained on at least two visits over a period of one to several weeks.
There are some data to suggest that ambulatory blood pressure measurement, which provides a measure of the average blood pressure over 24 hours, may be a better predictor of clinical cardiovascular outcome than clinic-based approaches; however, ambulatory blood pressure measurement is subject to many of the same errors as office blood pressure measurement.
The relationship between SBP and DBP and cardiovascular risk is continuous and graded. The actual level of blood pressure elevation should not be the sole factor in determining treatment. Clinicians should consider the patient's overall cardiovascular risk profile, including smoking, diabetes, abnormal blood lipid levels, age, sex, sedentary lifestyle, and obesity, in making treatment decisions.
Hypertension in children has been defined as blood pressure above the 95th percentile for age, sex, and height. Up to 28 percent of children have secondary hypertension (i.e., high blood pressure due to causes such as coarctation of the aorta, renal parenchymal disease, renal artery stenosis, and other congenital malformations). On the basis of expert opinion, several organizations, including the American Academy of Pediatrics (AAP), American Heart Association (AHA), and American Medical Association (AMA), recommend routine screening of asymptomatic adolescents and children during preventive care visits, based on the potential for identifying treatable causes of secondary hypertension, such as coarctation of aorta. However, there are limited data on the benefits or risks of screening and treating such underlying causes of hypertension in children. The decision to screen children and adolescents for hypertension remains a matter of clinical judgment.
Evidence is lacking to recommend an optimal interval for screening adults for high blood pressure. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-6) recommends screening every two years for persons with SBP and DBP below 130 mm Hg and 85 mm Hg, respectively, and more frequent intervals for screening those with blood pressure at higher levels.
A variety of pharmacologic agents are available to treat high blood pressure. JNC-6 guidelines for treatment of high blood pressure can be accessed athttp://www.nhlbi.nih.gov/guidelines/hypertension/jncintro.htm. The JNC-6-recommended goal of treatment is to achieve and maintain SBP below 140 mm Hg and DBP below 90 mm Hg, and lower if tolerated. Evidence indicates that reducing DBP to below 80 mm Hg appears to be beneficial for patients with hypertension and diabetes. In considering the effectiveness of treatment for hypertension, it must be noted that a given treatment's ability to lower blood pressure may not correspond directly to its ability to reduce cardiovascular events.
Nonpharmacologic therapies, such as reducing dietary sodium intake, potassium supplementation, increased physical activity, weight loss, stress management, and reduced alcohol intake, are associated with a reduction in blood pressure, but their impact on cardiovascular outcomes has not been studied. For those who consume large amounts of alcohol (i.e., more than 20 drinks in a week), studies have shown that reduced drinking decreases blood pressure. There is insufficient evidence to recommend single or multiple interventions or to guide the clinician in selecting among nonpharmacologic therapies.
The Scientific Evidence section that usually is included in USPSTF recommendation statements is available in the complete Recommendation and Rationale statement on the USPSTF Web site (http://www.uspreventiveservicestaskforce.org).
|The USPSTF grades the quality of the overall evidence for a service on a three-point scale (good, fair, or poor).|
|Good:||Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.|
|Fair:||Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies; generalizability to routine practice; or indirect nature of the evidence on health outcomes.|
|Poor:||Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.|
Recommendations of Others
Recommendations of the JNC-6 call for routine blood pressure measurement at least once every two years for adults with a DBP below 85 mm Hg and a SBP below 130 mm Hg.3 JNC-7 guidelines that update the JNC-6 guidelines for the treatment of high blood pressure can be accessed athttp://www.nhlbi.nih.gov/guidelines/hypertension/jncintro.htm. Similar recommendations have been issued by the AHA for adults beginning at age 20.4 The Canadian Task Force on Preventive Health Care is updating its recommendations on screening for elevated blood pressure. The American Academy of Family Physicians strongly recommends periodic measurement of blood pressure in patients older than 21.5 The American College of Obstetricians and Gynecologists recommends measuring blood pressure annually or as appropriate for women 13 and older.6 The AAP7; the National Heart, Lung, and Blood Institute8; the AHA9; Bright Futures: Guidelines for Health Supervision of Infants, Children and Adolescents10; and the AMA11 recommend regular blood pressure measurements starting at three years of age. The AAP further recommends against universal neonatal blood pressure screenings.12