New guidelines urge earlier, more aggressive treatment of high blood pressure

The relationship between blood pressure and the risk of heart disease and stroke has been demonstrated repeatedly in clinical studies. The JNC VII guidelines are in response to consistent epidemiological observations and clinical trial data that demonstrate the critical importance of lowering blood pressure, irrespective of age, gender, race or socioeconomic status.

The Framingham Heart Study followed men and women with blood pressure readings of 130-140/80-90 mm Hg, previously considered high-normal. Over the course of 12 years, the men had two times the risk of a cardiovascular event such as a heart attack, stroke or death than men with lower blood pressures. Women in this category were two and a half times more likely to suffer a cardiovascular event. As a result of this and other research information, the JNC lowered the bar on what is considered “normal” blood pressure for everyone.

The new “normal”
What we consider the new “ideal” blood pressure reading of 115/75 mm Hg was viewed until very recently as low-normal. It is a difficult goal for many people to attain, but JNC VII makes the case that millions of people in the prehypertension classification (those with blood pressure readings in the 120-139/80-89 mm Hg range) should aggressively pursue a healthier lifestyle to prevent the progression to overt hypertension.

Beginning at 115/75 mm Hg, the risk of cardiovascular disease doubles for each increment of 20/10 mm Hg. The new guidelines do not recommend drug therapy for prehypertension patients with the exception of patients with diabetes who have blood pressure readings over 130/80 mm Hg.

In addition to more aggressive blood pressure goals for everyone, JNC VII acknowledges that combination drug therapy is usually necessary for those with hypertension, defined as either stage I (140-159/90-99 mm Hg) or stage II (> 160/> 100 mm Hg). Half of these patients need at least two drugs to get to their blood pressure goal and one-third of these patients need three drugs to get to goal. The single-pill treatment is a myth; fewer than half of hypertensives are able to lower their blood pressure significantly with just one medication. The JNC also endorsed multidrug therapy as first-line therapy for most patients with stage II hypertension.

(Please see the blood pressure table.)

Multidrug therapy: what's best?
At this point, we do not have sufficient data to determine what combination of drugs is the best treatment for hypertension. A major research study, the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, better known as ALLHAT, compared effects of a diuretic with three other blood pressure-lowering drugs—

• calcium channel blocker,

• angiotensin converting enzyme (ACE) inhibitor

• alpha-adrenergic blocker.

Study of the alpha-adrenergic blocker was stopped early because of an increase in heart failure among those taking the drug. The effectiveness of the other three drugs—the diuretic, ACE inhibitor and calcium channel blocker—was the same for patients with uncomplicated high blood pressure. No one therapy resulted in better outcomes than another.

There were slightly higher rates of stroke among those taking the ACE inhibitor, but this group also had blood pressure readings that were 2 to 4 mm Hg higher than the other two groups, and for every 2 mm Hg change in systolic blood pressure, we see a 10 percent increase in stroke.

ALLHAT refuted the belief that calcium channel blockers cause increased mortality, and it dispelled the notion that ACE inhibitors have some magical effect although patients with type 1 diabetes and those with kidney disease generally benefit more from ACE inhibitors than the other options. Also, hypertensive African-American patients usually respond better to diuretics.

One-third of ALLHAT participants had diabetes at the beginning of the trial; an additional 10 percent developed diabetes during the trial. Those patients taking diuretics had a close to 50 percent higher risk of developing diabetes compared with patients in the ACE inhibitor arm of the study and a 16 to 30 percent higher risk than those taking calcium channel blockers.

Focus on systolic blood pressure
As people age, diastolic blood pressures tend to level out at age 55; however, systolic pressure rises continuously until age 90. Much of the uncontrolled hypertension in the U.S. is concentrated in older individuals and is related to inadequately treated systolic blood pressure. JNC VII advises physicians to treat these patients with drug therapy if the systolic pressure rises above 160.

Check your blood pressure regularly
Knowing your blood pressure reading and where it is in relation to what's considered normal is important in safeguarding your health. If you fall within this new prehypertension category, discuss with your doctor what lifestyle modifications you need to make to prevent becoming hypertensive.

If your levels are currently in the class I or II categories and you are not receiving medication to control your blood pressure, ask your physician why not. Also if you are taking medication for your blood pressure, but are still not at goal, talk with your physician about what multidrug therapy might be appropriate.

Earlier, more aggressive treatment is the watchword of JNC VII, but not everyone agrees. Since the JNC VII report was published, the European Society of Hypertension published its own revised guidelines. The European group does not endorse the prehypertension classification primarily because there is not sufficient data to indicate the best treatment for patients in this category. The European report places more emphasis on each patient's cumulative risk based not just on blood pressure readings, but on other risk factors as well, including family history, cholesterol and diabetes.

Dr. Mukherjee is an attending physician at Yale-New Haven Hospital and an associate clinical professor of medicine and cardiology at Yale School of Medicine. He is a partner with Cardiology Associates of New Haven, CT.