More About Prehypertension

In the previous two issues of The Journal of Clinical Hypertension, ¹ , ² newer guidelines for the management of hypertension were discussed. One of the more controversial recommendations in the recent US guidelines relates to newer definitions of normal and elevated blood pressures (BPs). The controversy is ongoing, with many physicians continuing to question the designation of prehypertension for a large segment of the population. Further comments about this debate seemed warranted.

Last year, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) ³ recommended new definitions and classifications of various levels of BP. In addition to simplifying the classification of hypertension into two stages (stage 1, 140/90 mm Hg‐159/99 mm Hg, and stage 2, >160/100 mm Hg), the committee designated levels of 120–139/80–89 mm Hg as prehypertension. The reasoning behind this new category was that long‐term epidemiologic studies had indicated a progressively increasing risk of a cardiovascular (CV) event as systolic BPs (SBPs) rose from 110 mm Hg. ⁴ From an epidemiologic point of view, risk would be minimized if BPs were as close to this number as possible.

While data indicate that the CV risk of a systolic pressure of 120 mm Hg is greater than 115 mm Hg and 130 mm Hg is greater than 120 mm Hg, it is also true that the increase in risk is not of great magnitude in a large number of people who do not have other risk factors for CV disease.

The JNC Committee members believed that the designation of prehypertension, rather than the previously recommended “high normal,” would alert the public and physicians alike to the concept that lowering BP from these levels would be advantageous. They believed that this new emphasis might increase adherence to lifestyle changes in order to lower BP. It was apparent that lifestyle changes were not being aggressively followed by many physicians or implemented by many patients.

But is changing the definition of “high normal” to prehypertension helpful? Reactions vary. There are many physicians who believe that designating someone as having a disease process as implied by the term “prehypertension” is counterproductive. Approximately 40–50 million people would be so classified and faced with the concern that they had a disease. Employment might conceivably be affected; insurance policies might be influenced.

Most importantly, being labeled “prehypertensive” could, and possibly would, produce anxiety in many healthy individuals. Prehypertensive BP levels may be significant and require intervention in a patient with diabetes, known heart disease, or the presence of other risk factors such as dyslipidemia, smoking history, or obesity with the metabolic syndrome. But in a nonobese, healthy, middle‐aged person with none of these risk factors and BPs of 130/85 mm Hg compared to 120/80 mm Hg, there is a very minimal increased risk of a CV event.

The designation, therefore, might be helpful in motivating a patient who has risk factors in addition to a prehypertensive BP level to correct them, to pay more attention to losing weight, reducing sodium intake, exercising more, moderating alcohol intake, etc.; but in a person with no other risk factors and nothing to correct, this designation may be counterproductive.

Many of us championed the concept years ago that “mild hypertension” (then defined as 140–160/90–105 mm Hg) should not be ignored and studies have proved this to be correct. ⁵ Lowering BP from levels consistently higher than 140/90 mm Hg has proved effective in reducing strokes, heart failure, and coronary heart disease events. But perhaps the term “prehypertension” is lowering the levels for intervention too much. The concern is that many physicians will choose to treat with medication if there are no lifestyle changes that need changing, or if the patient cannot lose weight, or will not exercise, etc. There are also some indications that patients are now requesting specific therapy if their BPs are in the prehypertensive range. Although it is possible that both physicians who decide to treat and patients who request treatment are correct, there are no treatment data to suggest that lowering BP from prehypertensive levels will reduce the risk of a CV event. The intent of the JNC 7 recommendations was not to advocate specific medication, but to stress lifestyle changes in this group of patients.

The other side of the argument is that there is some early evidence that patients with prehypertension may be somewhat different physiologically from those with optimal or normal BPs, i.e., <120/80 mm Hg. There are some data, for example, to indicate that people with BPs within the range of prehypertension (120/80 mm Hg–139/89 mm Hg) have some increase in left ventricular mass compared to those with more optimal pressures. There is some evidence that C‐reactive protein, a marker of inflammation, is higher in patients with prehypertension. ⁶ Elevated C‐reactive proteins have been linked to an increase in CV disease and these preliminary findings suggest that people with prehypertension may be more susceptible to heart disease than others. But some preliminary data also suggest that people with prehypertension are not at increased risk for stroke.

Numerous other studies are ongoing to determine whether people with prehypertension are at greater risk, not just as a result of BP levels but because of other factors. So the picture is not as clear as it should be to make clinical decisions.

HOW TO MANAGE PREHYPERTENSION

What does a physician do while awaiting more definitive information? Obviously, an ideal BP for everyone would be ≈120/80 mm Hg. If a patient has a BP of 130/80–85 mm Hg, I do not believe however that, at present, he/she should be labeled prehypertensive, even if there are some specific risk factors present. They should be told that the BP is higher than normal and, if there are risk factors that can be corrected, these should be specifically addressed. Exercise if the patient is sedentary, weight loss if the patient is obese, correction of blood glucose levels if abnormal, correction of dyslipidemia, smoking cessation, and moderation of alcohol are indicated according to the lifestyle suggestions that have been published in all of the JNC Reports. These interventions may result in fairly significant reductions in BP. For example, a weight loss of 20 lb might result in a decrease in SBP of ≈10–15 mm Hg; an increase in physical activity might result in a decrease in SBP of about 5–7 mm Hg; dietary sodium restriction might result in a decrease in SBP of about 4–5 mm Hg. These reductions are significant enough to reduce BP to a more optimal range. If BPs remain >120–125/80 mm Hg, but <140/90 mm Hg, I do not believe that specific medications are necessary, unless the patient is a diabetic or has evidence of heart or renal disease.

On the other hand, if a patient presents with BPs of 130–135/80–85 mm Hg and no other risk factors (is active, non‐obese, a nonsmoker, and nondiabetic with normal lipid levels), there is certainly no reason to either label them or create anxieties since, although their risk may be slightly greater than if BPs were lower, the risk is not sufficient to warrant the label or warnings of possible trouble in the future. If there are no interventions to institute, the patient should just be followed. Perhaps the patient will or will not develop BP levels that will warrant treatment in the future.

Occasionally, epidemiologists, who usually do not treat patients, will carry the day when guidelines are established; they may be correct in alerting the public and physicians to a problem. Whether or not they are correct can only be determined by prospective treatment trials. Oftentimes, however, epidemiologic data must be tempered by clinical experience and judgement; the prehypertension debate is a prime example of when clinical judgement should be utilized in making a treatment decision.