JNC 7 Speaker Remarks, Aram Chobanian, M.D.
Aram V. Chobanian, M.D.
Dean, Boston University School of Medicine
Provost, Boston University Medical Campus
Chair, Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure
Press Conference Remarks
May 14, 2003
Release of the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7)
Thank you, Dr. Lenfant. The guidelines serve to clarify findings from significant clinical trials and help physicians apply the latest scientific evidence to clinical practice. As someone who has been involved in the past five Joint National Committee reports and who chaired JNC 4, I can say that the task for the JNC 7 group was greater than in the past because of the extraordinary amount of new information that needed to be reviewed.
The recommendations that we have made are based on the evaluation of all of the available evidence—evidence which has provided us with greater understanding of the mechanisms associated with high blood pressure, the complications that evolve, and how to prevent such complications. The latest findings have been remarkably consistent, which contributed to a strong degree of consensus achieved among the members of the executive committee and the other experts from the National High Blood Pressure Education Program?s Coordinating Committee.
One of the key insights that we have gained since the last guidelines were developed in 1997 is the degree to which high blood pressure puts one at risk for heart disease, stroke, kidney damage, and other conditions. From the landmark NHLBI Framingham Heart Study, we have found that Americans? lifetime risk of developing hypertension is much higher than we previously thought. At age 55, those who do not have high blood pressure have a 90 percent chance of developing it at some point in their lives.
Furthermore, we have found that damage to arteries begins at fairly low blood pressure levels—levels previously considered ?normal.? This may be associated with an increased risk of heart disease and stroke, which continues to rise with each increment in blood pressure. The damage may begin long before people get treatment unless preventive action is taken.
At the same time that we are learning that blood pressure plays an even greater role in the development of cardiovascular disease and related complications, we have an aging population that is inherently at greater risk for all of these conditions. But the percentages of Americans who are aware that they have hypertension and who have it under control are reaching a plateau at rates that are unacceptable.
The guidelines simplify and streamline the recommendations to better help clinicians and patients to adopt the guidelines for the public?s health and well-being. As published in the new report, national survey data indicate that 70 percent of Americans are aware of their high blood pressure; 59 percent are being treated for it; and 34 percent of those with high blood pressure have it under control. These are the highest rates known since such data were first tracked some 25 years ago, when only 51 percent of Americans with hypertension had been diagnosed and only 10 percent had their hypertension under control. Nevertheless, we still must do better. The bottom line is that nearly one-third of Americans with high blood pressure aren?t aware of it, and two-thirds of those Americans with hypertension still do not have it adequately treated.
Several new items are presented in the report. These include a new classification of blood pressure, new treatment recommendations, and new recommendations on how to improve the current hypertension control rates.
A fundamental change in the guidelines is the new approach to categorizing blood pressure levels. Under the old guidelines, we classified blood pressure levels as optimal, normal, high-normal, or hypertensive. With JNC 7, we have adopted the categories of normal, prehypertension, and hypertension.
Normal blood pressure is less than 120 mm Hg over less than 80 mm Hg. This is the same level that was previously considered optimal.
The new category of ?prehypertension? is the most significant change in the classification scheme. Prehypertension is used to denote blood pressure levels in the 120 to 139 mm Hg systolic or 80 to 89 mm Hg diastolic range. Two important observations led to this new designation: 1) blood pressure increases steadily with age and, as stated earlier, most individuals will develop hypertension during their lifetime; and 2) data compiled from a number of studies indicate that the mortality rate for heart attacks, strokes, and other vascular diseases increases progressively from blood pressure levels as low as 115/75. To put this into perspective, for every 20/10 mm Hg rise in blood pressure above this level, there is a doubling in risk of death from cardiovascular problems.
The report recommends lifestyle changes in prehypertensive individuals to lower blood pressure and prevent the development of hypertension. These include weight reduction, exercise, adoption of the DASH eating plan, salt reduction, and limiting alcohol intake. The report also recommends that, for overall cardiovascular health, persons quit smoking. The implications and potential benefits of such healthier lifestyles could be great, particularly since about 22 percent of the adult population falls into the prehypertension category.
Let us now turn to the hypertension category.
Approximately 50 million individuals—or one in four adults—are hypertensive with blood pressure equal to or greater than 140 mm Hg systolic or equal to or greater than 90 mm Hg diastolic. As indicated earlier, only 59 percent of such individuals are currently on blood pressure-lowering treatment and 35 percent are controlled to less than 140/90. Systolic blood pressure has even worse control rates than diastolic hypertension. This is a particularly serious problem because high systolic blood pressure represents a very important cardiovascular risk factor after age 50.
Before I present to you the recommendations for treating patients with high blood pressure, let me first emphasize a key message of the new guidelines: patients with hypertension benefit from blood pressure lowering, whether it occurs as a result of lifestyle or drug therapies, or, in most cases, a combination of the two treatment approaches.
Lifestyle changes to lower blood pressure are strongly recommended for all individuals with hypertension. Reasonable reductions in blood pressure can be achieved if appropriate behavioral changes can be made. In fact, the blood pressure effects of weight reduction or adoption of the DASH eating plan can be comparable to those achieved with any single blood pressure medication.
The treatment algorithm developed by the JNC 7 considers three groups of patients with hypertension: 1) those with stage 1 hypertension without associated conditions; 2) those with more severe, or stage 2, hypertension without associated conditions; and 3) those with associated conditions that indicate use of specific classes of blood pressure-lowering medication.
The treatment goals are unchanged since the last set of guidelines. For patients with stage 1 or stage 2 uncomplicated hypertension, the goal blood pressure is less than 140/90. In some patients in the third group ? those with diabetes or chronic kidney disease ? a goal blood pressure of less than 130/80 may be desirable.
Many effective drugs are available for lowering blood pressure. The most important of these are diuretics, beta blockers, ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers. Clinical trials have shown benefits of each of these classes in reducing cardiovascular complications. Although individual classes of drugs may differ in usefulness for specific conditions, it should be emphasized that the most important benefits are related to lowering blood pressure. Overall, antihypertensive therapy has been associated with 35 to 40 percent average reductions in incidence of stroke, 20 to 25 percent in heart attacks, and more than 50 percent in heart failure. It is estimated from clinical data that in patients with other cardiovascular risk factors, a sustained 12-point reduction in systolic blood pressure over a 10-year period will prevent one death for every 10 patients treated. The risk of dementia in the elderly also appears reduced by blood pressure lowering.
In stage 1 uncomplicated hypertension, thiazide-type diuretics are recommended for most patients, although treatment with other drugs (ACE inhibitors, angiotensin receptor blockers, beta blockers, or calcium channel blockers) also may be considered in some. Two-thirds or more of patients require two or more drugs to control hypertension. The selection of the initial medication is probably less important than the need to achieve blood pressure control. Nevertheless, most clinical trials that have shown positive benefits of blood pressure lowering have included thiazide-type diuretics. They are effective, inexpensive, and have been shown to be very useful in most combination drug treatment programs.
Stage 2 hypertension is when a patient?s blood pressure hits 160 or higher systolic or 100 or higher diastolic. When this occurs, it is very likely that more than one medication will be required, and treatment may be initiated with two drugs, one of which should generally be a diuretic.
Patients who have hypertension associated with the co-morbid conditions detailed in Table 6 have compelling indications for starting therapy with those drugs that have been shown by clinical trials to be particularly beneficial for such conditions. For example, for those who have had a heart attack, beta blockers and ACE inhibitors are preferred; for those at high risk for coronary heart disease, ACE inhibitors, beta blockers, calcium channel blockers, as well as diuretics are recommended; and for chronic kidney disease, ACE inhibitors and angiotensin receptor blockers are drugs of first choice. This type of tailoring treatment to the specific needs of patients has been made possible by the extensive data obtained on each of the five major antihypertensive drug classes from several large-scale clinical trials, many of which have been supported by the NHLBI.
To obtain maximum benefits from blood pressure lowering, emphasis should also be placed on treating other cardiovascular risk factors including high blood cholesterol levels, smoking, diabetes, and overweight and obesity. People with high blood pressure are at greater than average risk for having such associated conditions, and their management is essential for achieving maximal cardiovascular health.
Dr. Roccella will now discuss more about what can be done to improve Americans? cardiovascular health.