"We need to prevent the rise of blood pressure with age, improve control, and recognize the importance of high-normal blood pressure in the development of hypertension," said committee chair Sheldon G. Sheps, MD, emeritus professor of medicine at the Mayo Clinic in Rochester, Minnesota.

Approximately 50 million U.S. adults have hypertension; nearly three quarters do not control their blood pressure to below 140/90 mm Hg. According to Sheps, after several decades of substantial decreases in age-related deaths from stroke and coronary heart disease, recent data indicate that the rates have begun to plateau and that deaths from stroke may even be increasing. In addition, heart failure has been on a continuous upward slope and endstage renal disease, for which hypertension is the second most common antecedent, has more than doubled since 1982.

Report Has Detractors

Although they agree that the report should help clinicians appreciate the importance of treating hypertension, Curt D. Furberg, MD, PhD, of Bowman Gray School of Medicine in Winston-Salem, North Carolina, and Bruce M. Psaty, MD, PhD, of the University of Washington in Seattle, assert that, in places, the guidelines are less evidence-based than consensus-based (Lancet. 1997; 350:1413-4). Because so much expert opinion was included, Psaty argued, the guidelines provide an exception for almost every rule, making it "difficult to glean the central message from the chaff."

"We must remember these are guidelines, not rules," responded Jerome D. Cohen, MD. "But they are clearly evidence-based." Cohen, from St. Louis University Health Sciences Center, is an executive committee member who represented the American College of Physicians in writing the guidelines. Acknowledging that "evidence takes you only so far," he added, "we did indicate [in the guidelines] where the evidence is strong and where it is less strong."

Sheps added that the report had more than 100 contributors, reviewers, and consultants and was endorsed by 45 organizations. Furberg and Psaty were two of five contributors who chose not to endorse the final report. Clinicians will have to determine for themselves whether the guidelines are helpful.

The first indication of the guidelines' new focus is the title: Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (Arch Intern Med. 1997; 157:2413-46).* For the first time, the word prevention is included, primarily because of a recent study showing that the DASH (Dietary Approaches to Stop Hypertension) diet, which is rich in fruits, vegetables, and low-fat dairy foods and low in saturated and total fat, can substantially lower blood pressure (N Engl J Med. 1997; 336:1117-24). The report contains details on the diet plus recommendations on alcohol consumption that, for the first time, vary by sex and body size. Recommendations on aerobic exercise, sodium reduction, and weight loss are similar to earlier guidelines.

*The guidelines on hypertension can also be found on the World Wide Web (http://www.nhlbi.nih.gov/nhlbi/nhlbi.htm) or ordered through the NHLBI Information Center at 301-251-1222.

The committee constructed new risk strata to guide treatment decisions on the basis of the level of hypertension and such risk factors as smoking, family history, dyslipidemia, and diabetes (Box [Table 1]). For example, management of a patient with a blood pressure of 138/89 mm Hg (considered high-normal) and no other risk factors would begin with diet and activity modification for up to 1 year. However, if the same patient also has diabetes, drug therapy is recommended as the first-line approach, even with the relatively low blood pressure and no signs of overt heart or kidney disease. The risk stratification is important, according to Cohen. "It means treating a patient, not a blood pressure."

Specific drug categories are prescribed for different clinical indications. For example, patients with diabetes or kidney damage and hypertension should receive angiotensin-converting enzyme (ACE) inhibitors as first-line therapy. Older patients with isolated systolic hypertension should first be treated with diuretics.

One of the drug indications in the report that has generated controversy is the suggestion that isolated systolic hypertension can be treated with certain calcium antagonists. Critics point to studies showing negative outcomes related to calcium antagonists. But, according to Sheps, the data are inconsistent. In addition, the committee was impressed by the Systolic Hypertension in Europe (Sys-Eur) trial, which compared the effects of a dihydropyridine plus other optional drugs with those of placebo. The trial was stopped after 2 years because patients in the active-treatment group had a 42% reduction in stroke (Lancet. 1997; 350:757-64). Sheps described the committee's evaluation of this study and other literature: "While diuretics are still preferred, if an alternative is needed, consider long-acting dihydropyridine calcium antagonists."

The dihydropyridine used in the European trial, nitrendipine, is not available in the United States, but the committee determined that other dihydropyridines should produce the same effects. The report recommends that short-acting calcium antagonists be avoided except in a few circumstances.

As with treatment choices, proposed blood pressure targets in the guidelines vary depending on concurrent conditions. For example, the target for a patient with diabetes or renal failure is 130/85 mm Hg. But for a patient with renal failure showing marked damage with greater than 1 g/day of proteinuria, the target blood pressure is 125/75 mm Hg. "It's difficult to achieve those goals," Sheps admitted. "It would require multiple drugs, but the data are there to show the benefit."

Sheps does not expect these recommendations to remain static. The National High Blood Pressure Education Program has committed to providing advisories as new evidence becomes available from the more than 30 trials testing different pharmacologic agents, such as the newer calcium antagonists and ACE inhibitors, in various populations with hypertension. But he emphasized that action to control hypertension should begin now. "I don't think people should wait."

-Cori Vanchieri