New physician guidelines for the prevention and treatment of high blood pressure were released today by the National Heart, Lung, and Blood Institute (NHLBI). The guidelines, approved by the Coordinating Committee of the NHLBI's National High Blood Pressure Education Program, contain updated treatment strategies, including a system of stratifying patients into risk groups and the idea of compelling indications for certain antihypertensive medications.
The guidelines, known as The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI), also reveal a disturbing trend in the treatment and control of high blood pressure or hypertension and in the rates of associated diseases such as stroke and coronary heart disease (CHD).
"Despite tremendous progress in the last 25 years in the awareness, treatment, and control of hypertension, these dramatic improvements have slowed. New data show a slight rise in the rate of stroke, increases in both end-stage renal disease and heart failure, and a leveling in the death rate for people with coronary heart disease. These statistics signal the need for a renewed effort by physicians and patients to prevent and treat hypertension. The guidelines can serve as a tool in meeting this major public health goal," asserted NHLBI Director Dr. Claude Lenfant.
The complete text of the JNC VI report will be published in the November 25 issue of the Archives of Internal Medicine, a journal of the American Medical Association.
The chairman of the Joint National Committee, Dr. Sheldon Sheps, described several critical goals identified in JNC VI. "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 Dr.Sheps who is also Emeritus Professor of Medicine, Mayo Clinic.
One of the most significant changes in JNC VI, compared to the previous guidelines issued in 1992, is the concept of stratifying hypertension patients by blood pressure stage (1, 2, 3) and into risk groups (A, B, and C) to guide treatment decisions. These risk groups are based on the presence of risk factors like high blood cholesterol and on related organ damage. For example, a patient in Risk Group A with stage 1 hypertension (140-159 systolic and 90-99 diastolic) with no cardiovascular disease, organ damage, or other risk factors would try lifestyle changes for 1 year before taking drugs. By contrast, the earlier guidelines suggested that such patients should try lifestyle changes for only 3 to 6 months before starting medication. Regardless of risk group, JNC VI recommends lifestyle changes for all patients on drug therapy.
About 50 million U.S. adults have hypertension. Untreated hypertension can damage the kidneys and lead to stroke, heart attack, and heart failure. Heart disease and stroke are the first and third leading causes of death, respectively, in the U.S.
Hypertension is defined as systolic blood pressure averages of 140 mm Hg or greater and/or diastolic blood pressure averages of 90 mm Hg or greater. The systolic pressure is the pressure of blood in the vessels when the heart contracts. Diastolic pressure is the pressure of the blood between heartbeats when the heart is at rest.
For patients with uncomplicated hypertension, JNC VI recommends diuretics and beta blockers as the first line of treatment. Other drugs, sometimes in combination with diuretics or beta blockers, are available to treat patients with complications.
For the first time, the hypertension guidelines establish "compelling indications" for specific drugs when patients have certain clinical conditions. For example, older people with isolated systolic hypertension should first be treated with diuretics. Patients with diabetes, kidney damage, and high blood pressure should begin treatment with ACE inhibitors. Heart attack (in conjunction with hypertension) is a compelling indication for the prescription of beta-blockers and, in certain instances, ACE inhibitors. Heart failure should first be treated with ACE inhibitors and diuretics.
In general, JNC VI advises that most patients should be started on a low dose of the initial drug, that long-acting formulas are usually preferable, and that even if a diuretic is not chosen as the first drug, it can be used to enhance the effects of other medications. The cost of drug therapy can interfere with hypertension control, according to JNC VI. Cost-cutting measures include using combination tablets, generic drugs, and dividing some types of large tablets, which may be less expensive.
The new guidelines reiterate earlier warnings from the NHLBI about negative heart effects of a type of calcium channel blocker called short-acting nifedipine. This drug should be used only with great caution, if at all. However, JNC VI suggests that certain long-acting calcium channel blockers--including long-acting nifedipine--are alternate choices for older patients with isolated systolic hypertension, the most common form of hypertension in the elderly.
JNC VI addresses treatment considerations for older persons with hypertension and for a number of other special populations, including African Americans. Compared with whites, hypertension in African Americans develops earlier in life and average blood pressures are much higher. As a result, African Americans have an 80 percent higher rate of death from stroke, a 50 percent higher rate of death from heart disease, and a 320 percent greater rate of hypertension related end-stage renal disease than those in the general population. Lifestyle changes are particularly important for African Americans who have a high prevalence of risk factors for heart disease--such as obesity--and also increased sensitivity to salt. Diuretics should be the drug of first choice for this population, advises JNC VI.
A major emphasis of the new guidelines is the recommendation of a population-wide approach to prevent high blood pressure through lifestyle changes. "Such a strategy could affect overall cardiovascular deaths and disability as much as or more than that of treating only those with established disease," said Dr. Sheps.
A healthy diet is an important part of this strategy. For the first time, the guidelines encourage the population-wide adoption of a specific diet. The diet was evaluated in a recent study, Dietary Approaches to Stop Hypertension (DASH). DASH found that eating a diet rich in fruits, vegetables, and low fat dairy foods with reduced saturated and total fats significantly lowers blood pressure.
In addition to the DASH diet, the JNC VI recommends the following lifestyle changes for both the prevention and treatment of high blood pressure: reduce daily sodium intake to no more than 2.4 grams of sodium or 6 grams of sodium chloride, which is about 1 tsp. of salt (reduce processed foods); maintain adequate intake of dietary potassium (90 mmol or 3.5 grams--good sources include bananas, orange juice, potatoes, yogurt, prunes, winter squash); lose weight if overweight; limit alcohol intake to no more than 1 oz. ethanol (e.g., 24 oz. beer or 10 oz. wine) per day for men or « oz. ethanol per day for women; increase aerobic physical activity (30 to 45 minutes most days of the week); and for overall cardiovascular health, stop smoking and reduce dietary saturated fat and cholesterol.
The Joint National Committee is a central activity of the NHLBI's National High Blood Pressure Education Program, a patient and professional education program now celebrating its 25th anniversary.
For a copy of the guidelines, check the NHLBI website: http://www.nhlbi.nih.gov/guidelines/archives/jnc6/jnc6_archive.pdf. To arrange an interview with Dr. Sheps, call Shelly Plutowski, Mayo Clinic News Bureau, (507) 284-2417.
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