Guidelines address ‘prehypertension’ – Suggest Lifestyle Interventions
Michele G. Sullivan
NEW YORK — New hypertension guidelines issued by the National Heart, Lung, and Blood Institute reflect an urgent need to intervene earlier and more aggressively to prevent high blood pressure from causing serious health consequences.
The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) redefines blood pressure categories and favors diuretic-based therapy. Unveiled at the annual meeting of the American Society of Hypertension, the guidelines are based on the results of more than 30 clinical trials conducted since the previous guidelines (JNC VI) were issued in 1997.
In a bold move that has sparked considerable debate, JNC 7 defines an entirely new class of “prehypertension” that applies to patients with a systolic blood pressure of 120-139 mm Hg or a diastolic blood pressure of 80-89 mm Hg. This category includes about 45 million Americans, many of whom have previously been told that their blood pressure is normal.
Patients in this group merit attention–in the form of lifestyle-based intervention–because they face a significantly increased risk of developing hypertension and its complications, including kidney damage, cardiovascular disease, and stroke, said Dr. Aram Chobanian, dean of the Boston University School of Medicine and JNC 7 chairman.
“To put it into perspective, for every 20/10 mm Hg rise in blood pressure above 115 / 75 mm Hg, there is a doubling in risk of death from cardiovascular problems,” he said.
Studies suggest that mortality rates for heart attack, stroke, and other vascular disease increase progressively starting at blood pressure levels as low as 115/70 mm Hg. Blood pressure tends to rise with age, so patients at 120/80 mm Hg at age 50 have a 90% lifetime risk of becoming hypertensive, Dr. Chobanian said. That, he said, points up the critical importance of early intervention in prehypertensive patients and aggressive intervention in hypertensive patients, especially those who have heart disease or are at high risk for heart disease, diabetes, or chronic kidney disease.
But critics of JNC 7 maintain that the guidelines fail to distinguish between etiologies of hypertension and imply that all patients will benefit from the same medications. Instead of unnecessarily creating a new group of prehypertensive patients, the critics argue, the guidelines should have focused on treatment of patients who are truly hypertensive. (See box.)
For patients with prehypertension, JNC 7 recommends lifestyle modifications, not pharmacotherapy Physicians should explain that a lowsodium diet, exercise, weight loss, and moderation of alcohol intake will lower blood pressure and prevent the development of hypertension (JAMA 289:2560-71, 2003).
“The implications and potential benefits of such healthier lifestyles could be great,” Dr. Chobanian explained, “particularly since about 22% of the adult American population falls into the prehypertensive category
JNC 7 defines stage 1 hypertension as a systolic blood pressure of 140-159mm Hg or a diastolic blood pressure of 90-99 mm Hg, and stage 2 hypertension as a systolic blood pressure of at least 160 mm Hg or a diastolic blood pressure of at least 100 mm Hg. The redefined stage 2 combines what were previously designated as stages 2 and 3.
Treatment goals remain unchanged from JNC VI: Patients with uncomplicated stage 1 or 2 hypertension should strive for blood pressure of less than 140/90mm Hg, and patients with preexisting complications should aim for a blood pressure of less than 130/80 mm Hg.
Almost all patients with uncomplicated stage 1 hypertension should be started on a thiazide-type diuretic, the guidelines recommend. This is based on evidence from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) that these agents are unsurpassed at lowering blood pressure. The drugs are inexpensive, and patients are highly likely to adhere to prescribed dosing. Major studies have shown that diuretics are underutilized in hypertension treatment, the report notes.
But the guidelines state that ACE inhibitors, angiotensin receptor blockers, 3-blockers, and calcium channel blockers also may be considered as first-line therapy in certain high-risk conditions. “The selection of the initial medication is probably less important than the need to achieve blood pressure control,” Dr. Chobanian said.
If patients have stage 2 hypertension, or if initial therapy fails to achieve the blood pressure goal, other drugs should be added. Many patients will require two, or even three, medications to achieve control. When pharmacotherapy is initiated with two drugs at this stage, one of those should generally be a diuretic.
Drug choice is especially important when treating patients with preexisting comorbid conditions. Clinical trials have shown that certain drugs are particularly effective for hypertension associated with “compelling indications.” (See chart.)
Physicians should be especially vigilant about systolic blood pressure in patients aged 50 years or older, since systolic blood pressure .of more than 140 mm Hg in these patients is a more important risk factor than diastolic pressure. The guidelines also recognize the importance of addressing other cardiovascular risk factors, including hypercholesterolemia, smoking, and excess weight.
Patient motivation is a key factor, the guidelines emphasize. Patients and physicians should establish a positive relationship based on trust and empathy then agree on a blood pressure goal and a patient-centered strategy for achieving it. Selfmonitoring of blood pressure can be useful, as can physician sensitivity to the patient’s culture, beliefs, and experiences.
A summary of the guidelines for use by clinicians, called ‘JNC 7 Express,” is available online at www.nhlbi.nih.gov/guidelines/hypertension.
COPYRIGHT 2003 International Medical News Group
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