Program Overview

An estimated 70 million American adults have prehypertension, a blood pressure (BP) classification adopted in 2003 by the Seventh Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of Hypertension (JNC7). Prehypertension describes a range of BP levels that had previously been categorized as normal or borderline: 120-139 mm Hg systolic and/or 80-89 mm Hg diastolic.

The suggested management of prehypertension includes observation and lifestyle changes; however, there is still confusion among both physicians and patients about how to best address prehypertension.

Many patients with prehypertension use dietary supplements (nutraceuticals) to try to prevent progression to overt hypertension. As a consequence, physicians are being exposed to a wide variety of nutraceuticals, many only recently introduced. It is vital that physicians have a broad understanding of the impact of these agents on prehypertension, hypertension, and other cardiovascular risk factors, as well as their interactions with other drugs.

This program features presentations from a closed symposium, titled “The Impact of Dietary Supplements on Hypertension,” held April 27, 2006, in Santa Monica, California.


Learning Objectives

At the conclusion of this activity, participants should be able to:

  • Review the definition of prehypertension and the cardiovascular risk associated with prehypertension
  • Discuss clinical approaches to the management of prehypertension
  • Assess the influence of dietary supplements on blood pressure and review commonly used agents to establish their impact on traditional hypertension
  • Evaluate clinically proven alternative approaches to renin-angiotensin system blockade and their impact on hypertension and hypertension management.


Statement of Need and Purpose

An estimated 70 million American adults1 (40% of men, 23% of women)2 have prehypertension, a BP classification adopted in 2003 by the Seventh Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of Hypertension (JNC7). Prehypertension describes a range of BP levels that had previously been categorized as normal or borderline: 120-139 mm Hg systolic and/or 80-89 mm Hg diastolic.3

JNC6 Classification (1997) Blood Pressure (mm Hg) JNC7 Classification (2003)
Optimal <120/80 Normal
Normal 120-129/80-84 Prehypertension
Borderline 130-139/85-89
Hypertension ≥140/90 Hypertension
    Stage 1 140-159/90-99 Stage 1
    Stage 2 160-179/100-109 Stage 2
    Stage 3 ≥180/110

Source: Seventh Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of Hypertension3

Prehypertension is not a disease category, and, in most cases, patients are not candidates for drug therapy. However, prehypertension does increase a patient’s risk for developing hypertension, with the JNC7 finding that each incremental BP increase of 20/10 mm Hg above 115/75 mm Hg doubles cardiovascular disease (CVD) risk.3

Prehypertension can progress rapidly to hypertension. In a study evaluating the rate of progression of prehypertension to hypertension, 55% of prehypertensive individuals younger than 65 years and 75% older than 65 years developed hypertension within 4 years.4 In a randomized placebo-controlled trial to prevent progression from prehypertension to hypertension, 40% of subjects receiving placebo developed hypertension over 2 years.5

The prevalence of prehypertension in African Americans younger than 40 years is greater than in whites or Mexican Americans in the same age-group; conversely, the prevalence in African Americans older than 40 years is lower than the other groups due to the higher prevalence of hypertension in the younger age-group.1

Risk factors for CVD are more common in patients with prehypertension than in normotensive individuals. The National Health and Nutrition Examination Survey (NHANES, 1999-2000) found that, after adjusting for age, sex, and race, individuals with prehypertension were 1.65 times more likely to have at least one CVD risk factor (cholesterol ≥240 mg/dL, diabetes mellitus, body mass index [BMI] ≥30 mg/m2, or smoking).1 Another study found that, after adjusting for age, body mass, lipid levels, and other potential confounding factors, prehypertensive individuals had a higher prevalence of inflammatory markers linked to atherosclerosis (C-reactive protein, tumor necrosis factor-alpha, homocysteine, and elevated white blood cell counts).6

Prehypertension is associated with an increase in incident myocardial infarction and coronary artery disease, but not stroke.7 The increased risk of CVD development is pronounced in African Americans and in patients with diabetes mellitus, elevated BMI (>30 kg/m2), and/or low-density lipoprotein (LDL) cholesterol.8 However, research has found that, after adjusting for age, race, sex, and CVD risk factors, prehypertension is not an independent risk factor for increased mortality.9

To reduce BP, prevent or delay the onset of hypertension, and enhance antihypertensive drug efficacy, the JNC7 recommends lifestyle modifications that include weight loss, a healthy diet, limited alcohol intake, and aerobic exercise (30 minutes/day on most days). Furthermore, individuals who also have diabetes or kidney disease should be considered for drug therapy if lifestyle modification alone fails to reduce their blood pressure to ≤130/80 mm Hg.3

Healthy diets have been shown to reduce BP. The Dietary Approaches to Stop Hypertension (DASH) diet, which is rich in fruits, vegetables, and low-fat dairy products, and low in dietary cholesterol and saturated and total fat, reduces BP by 8-14 mm Hg and is recommended by the JNC7.3,10 A low-sodium (≤2400 mg/day) DASH diet can further reduce BP by 2-8 mm Hg.3

Although the JNC7 states that prehypertensive individuals without other risk factors are not candidates for drug therapy,3 evidence in support of intervention may be emerging. In a 2-year trial of candesartan (an angiotensin receptor blocker) vs. placebo in patients with prehypertension, 40% of participants in the placebo group developed hypertension compared with 14% in the candesartan group.5

The potential impact of prehypertension on public health is significant; likewise, reducing BP levels and preventing the transition from prehypertension to hypertension has the potential to significantly reduce the incidence of CVD.8


References:

  1. Greenlund KJ, Croft JB, Mensah GA. Prevalence of heart disease and stroke risk factors in persons with prehypertension in the United States, 1999-2000. Arch Intern Med. 2004;164:2113-2118.
  2. Wang Y, Wang QJ. The prevalence of prehypertension and hypertension among US adults according to the new joint national committee guidelines: new challenges of the old problem. Arch Intern Med. 2004;164:2126-2134.
  3. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. U.S. Department of Health and Human Services. 2004. Available at: http://www.nhlbi.nih.gov/guidelines/hypertension/jnc7full.htm. Accessed February 1, 2007.
  4. Vasan RS, Larson MG, Leip EP, Kannell WB, Levy D. Assessment of frequency of progression to hypertension in non-hypertensive participants in the Framingham Heart Study: a cohort study. Lancet. 2001;358:1682-1686.
  5. Julius S, Nesbitt SD, Egan BM, et al, for the Trial of Preventing Hypertension (TROPHY) Study Investigators. Feasibility of treating prehypertension with an angiotensin-receptor blocker. N Engl J Med. 2006;354:1685-1697.
  6. Chrysohoou C, Pitsavos C, Panagiotakos D, Skoumas J, Stefanadis C. Association between prehypertension status and inflammatory markers related to atherosclerotic disease: The ATTICA Study. Am J Hypertens. 2004;17:568-574.
  7. Qureshi AI, Suri MF, Kirmani JF, Divani AA, Mohammad Y. Is prehypertension a risk factor for cardiovascular disease? Stroke. 2005;36:1859-1863.
  8. Kshirsagar AV, Carpenter M, Bang H, Wyatt SB, Colindres RE. Blood pressure usually considered normal is associated with an elevated risk of cardiovascular disease. Am J Med. 2006;119:133-141.
  9. Mainous AG 3rd, Everett CJ, Liszka H, King DE, Egan BM. Prehypertension and mortality in a nationally representative cohort. Am J Cardiol. 2004;94:1496-1500.
  10. Appel LJ, Sacks FM, Carey VJ, for the OmniHeart Collaborative Research Group. Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial. JAMA. 2005;294:2455-2464.