Prehypertension revisited.

The Seventh Joint National Committee on the Prevention, Detection, Evaluation and Treatment of Hypertension (JNC-7) introduced the term “prehypertension” to designate individuals whose systolic blood pressure (BP) levels are in the range of 120 to 139 mm Hg and diastolic BP between 80 and 89 mm Hg.1,2 The decision to establish this new BP category was based on a number of factors. Several studies had indicated that BP in most societies increases with age, and in Framingham Heart Study participants, 90% of those whose BP was normal at age 55 years ultimately developed hypertension in their lifetime.3 Furthermore, in recent observational studies in adults between 40 and 80 years of age, the risk of cardiovascular disease (CVD) increased progressively from levels as low as 115/75 mm Hg upward with a doubling of the incidence of both coronary heart disease and stroke for every 20/10mm Hg increment of BP.4 The prehypertension designation was established to focus attention on a segment of the population who were at higher-than-normal CVD risk and in whom therapeutic approaches to prevent or delay the onset of hypertension would be of value. As part of its deliberations, the JNC-7 considered whether a diagnosis of prehypertension might have a negative influence on an individual’s employment or insurance status or create undue anxieties in some subjects. The committee also discussed whether dealing with large numbers of prehypertensive individuals might place excessive burdens on clinicians who already were having difficulty managing hypertensive patients or might lead to an excessive use of antihypertensive drugs to control prehypertension. However, such concerns were considered to be minor when compared with the potential benefits of dealing more effectively with the growing epidemic of hypertension in the United States. Many articles have been published on prehypertension since release of the JNC-7 report in 2003. New data have been provided on its rate of progression to hypertension, its prevalence and association with other CVD risk factors, its relationship to the development of CVD, and its therapy. The rate of progression of prehypertension to hypertension can be relatively rapid, particularly in those whose BPs lie in the upper portion of the prehypertension range and in elderly individuals. In Framingham Study participants with BP levels in the 120 to 129/80 to 84 mm Hg range, the BP progressed over 4 years to hypertensive levels in 17.6% of individuals between 30 and 64 years of age and in 25.5% of those 65 years of age.5 In the group with BP levels in the 130 to 139/85 to 89 mm Hg range, the incidence of hypertension was 37.3% and 49.5% for the 30to 64-year and 65-year groups, respectively. In the TRial Of Preventing HYpertension (TROPHY) study, 40% of prehypertensive individuals receiving a placebo developed hypertension over 2 years of follow-up.6 Because of these rates of progression, annual or biannual monitoring of BP in prehypertensive persons would seem appropriate. The prevalence of prehypertension in the United States as estimated from the 1999 to 2000 National Health And Nutrition Survey (NHANES) data is 70 million in the age group of 20 years.7 Surprisingly, many more men (42 million) than women (28 million) have prehypertension. The percentage prevalence of prehypertension in blacks seems roughly similar to that in whites. Abnormalities in other CVD risk factors are more common in prehypertensive than normotensive individuals. A study of the 1999 to 2000 NHANES data has suggested that 64% of prehypertensive subjects have 1 other abnormal CVD risk factor7; the percentage increased to 94% in those 60 years of age. In a separate investigation, 93% of prehypertensive subjects were reported to have 1 other CVD risk factor abnormality.8 With respect to specific risk factors, the risk ratios for obesity, dyslipidemia, insulin resistance, metabolic syndrome, and diabetes are all greater in prehypertensive than normotensive subjects and are intermediate between those with normotension and hypertension.9–12 Microalbuminuria is also more common in prehypertension than normotension13 as are abnormalities in circulating markers of inflammation, such as C-reactive proteins, interleukin 6, and tumor necrosis factor.14,15 Prehypertension is associated with an increased incidence of CVD, particularly in those with BP levels in the 130 to 139/85 to 89 mm Hg range16,17 and those with diabetes or glucose intolerance.12,17,18 In a study of 11 116 subjects followed for 10 years, prehypertensive persons demonstrated a significant increase in the incidence of myocardial infarction but not of stroke as compared with normotensive subjects.19 In a separate investigation, mortality from CVD was significantly greater in prehypertensive than normotensive individuals, but the differences were no longer present when adjustments were made for the levels of other CVD risk factors.8 How best to manage prehypertension has been the subject of recent debate. The JNC-7 report has recommended the adoption of healthy lifestyles to achieve BP goals except in prehypertensive subjects with diabetes or chronic renal disease in whom drug treatment is also advocated.1 Several studies have demonstrated the efficacy of dietary approaches, alone or in combination with other lifestyle modifications, to The opinions expressed in this editorial are not necessarily those of the editors or of the American Heart Association. From Boston University School of Medicine, Mass. Correspondence to Aram V. Chobanian, Boston University School of Medicine, 650 Albany St, Boston, MA 02118. E-mail [email protected] (Hypertension. 2006;48:812-814.) © 2006 American Heart Association, Inc.