Abstract & Commentary
Synopsis: A new classification of blood pressure in adults is suggested, with normal blood pressure (BP) as < 120 mm Hg and < 80 mm Hg.
Source: Chobanian AV, et al. JAMA. 2003;289:2560-2571.
The long-awaited JNC-7 report was recently published in summary form; a more comprehensive manuscript will be forthcoming. JNC-7 takes into account many of the randomized controlled trials dealing with hypertension (HBP) published over the past few years, and thus, is very much up to date. Some highlights of the report are as follows:
1. A new classification of blood pressure in adults is suggested, with normal blood pressure (BP) as < 120 mm Hg and < 80 mm Hg. A new category, prehypertension, is defined as systolic pressure (SBP) 120-139 or diastolic (DBP) 80-89. In this category, pharmacologic treatment is indicated only if there is a "compelling indication," such as diabetes, vascular disease, or kidney disease. Stage 1 hypertension is now defined as SBP 140-159 or DBP 90-99, and stage 2 hypertension is SBP > 160 or DBP > 100. Drug treatment is mandated for both stages, with combination therapy more likely to be necessary in stage 2.
2. A thiazide-type diuretic is recommended as the first drug to be used except in patients with hyponaturemia or gout. Furthermore, a diuretic should be part of any multidrug combination.
3. The prevalence of hypertension is 50 million individuals in the United States. JNC-7 emphasizes the marked prevalence of HBP in the elderly; data from the Framingham Heart Study suggests that individuals with a normal BP at age 50-60 have a 90% lifetime risk of developing HBP. Hypertension is the most common primary diagnosis in the United States, with only modest gains in awareness, treatment, and control of BP over the past 25 years. Recent data suggest that only one-third of the hypertensive population is under adequate control (NHANES survey).
4. Recent clinical trials indicate that antihypertensive treatment can reduce stroke incidence by 35-40%, acute myocardial infarction by 20-25%, and more than a 50% reduction in new onset heart failure.
5. There was an emphasis on how to accurately determine BP measurements in the outpatient setting, (2 measurements in subjects seated quietly for at least 5 minutes).
6. JNC-7 recommends self-measurement of BP at home to determine response to therapy, confirm adherence, etc. The goals of antihypertensive therapy are stated as "the reduction of cardiovascular and renal morbidity and mortality." JNC-7 emphasizes that the "primary focus should be on achieving the systolic BP goal." A generic target for BP of < 140/90 mm Hg is associated with decreased cardiovascular complications. In high-risk patients, such as those with diabetes or renal disease, the goal is < 130-80 mm Hg, which Framingham considers to be the optimal blood pressure.
7. Healthy lifestyles are strongly emphasized throughout the report, including weight control; adoption of the DASH diet, with increased intake of potassium and calcium rich foods, fruits and vegetables; moderation of alcohol consumption to < 2 drinks a day; and regular physical activity.
8. Pharmacologic therapy is simplified, with the admonition that a thiazide-type diuretic should be the basis of therapy, followed by any of the major classes of antihypertensive drugs. These include angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARB), beta blockers, and calcium channel blockers. Virtually no mention is made of outlier drugs for BP control in JNC-7 (eg, alpha blockers or CNS active drugs, such as clonidine). Chobanian and associates strongly emphasize that the majority of patients with HBP will require 2 or more medications to achieve goals. Furthermore, they recommend that drugs from different classes be used in polypharmacy. Therapy may be initiated with 2 drugs, particularly if baseline blood pressure is high and/or the subject is at increased vascular risk. Follow-up should occur monthly after initiation, and more frequently in stage 2 patients. When BP is at goal and stable, follow-up visits are recommended at 3-6 month intervals. Co-morbidities or high-risk conditions are emphasized, requiring specific choices of drug classes. These are quite obvious and include beta blockers for individuals with co-existing ischemic heart disease and an ACE inhibitor for those with heart failure, acute coronary syndromes, or postmyocardial infarction. Aldosterone antagonists are also recommended in heart failure. Heart failure patients with hypertension should have "fastidious BP and cholesterol control," with the mainstay of hypertensive therapy being an ACE inhibitor and beta blocker. ARBs and aldosterone blockers, along with loop diuretics, are also appropriate for late-stage heart failure. Diabetics should be routinely treated with 2 or more drugs, with an optimal blood pressure target. Physicians need to keep in mind that ACE inhibitors and ARBs favorably affect progression of diabetic renal disease.
9. A newly recognized high-risk group is individuals with chronic kidney disease, as manifest by creatinine of > 1.3 in women and > 1.5 in men or a GFR of < 60 mLs/m2. Such individuals should be targeted for a BP < 130/80 mm Hg. Again, drugs acting on the renin angiotensin system (RAS) are suggested. Chobanian et al accept a modest rise in serum creatinine of up to one-third over baseline if and when an ACE or an ARB is used.
10. Emphasis is given to obesity and the metabolic syndrome, stressing the high-risk aspects of these increasingly common conditions. Hypertensive control in the elderly is also stressed. JNC-7 recommends starting with smaller drug doses in the elderly, watching for postural hypotension, while stressing control of systolic BP.
The conclusion of the report deals with how to best motivate patients with hypertension, stressing individual engagement in the process with a "patient-centered strategy and an estimation of the time needed to achieve the goal" established by the patient and the physician. Chobanian et al stress physician-stimulated motivation and empathy as influencing adherence to therapy. A final comment highlights population increases in consumption of saturated fat and salt and decreases in physical activity as being partly responsible for the epidemic of overweight and obesity, contributing to hypertension and related conditions.
Comment by Jonathan Abrams, MD
In the heels of many recent well-performed trials in hypertension, including ALLHAT, LIFE, HOPE, RENAAL, PROGRESS, UKPDS, ANBP2, as well the recent guidelines for treatment of hypertension in African-Americans and numerous algorithms and guidelines, there are few to no surprises in the official JNC-7 report. There has been considerable noise and confusion in the hypertension world for many years, particularly relating to the controversy over the safety of thiazide diuretics and the concern raised by some that calcium channel blockers may actually induce adverse events. The premature discontinuation of the alpha blocker arm in ALLHAT raised concerns that there may be unproven adverse effects of some classes of drugs. JNC-7 does not favor any single class of drugs, and even its recommendations for initiating therapy with a thiazide is not revolutionary. These drugs have been the cornerstone of hypertension guidelines for years, although they have fallen out of favor, in part to the aggressive marketing of the newer classes of agents, such as drugs that interfere with the RAS system and the calcium channel blockers. I view the most important aspects of this report to be as follows:
1. The emphasis on the concept that lower is better. Blood pressure control should be analogous to our approach to LDL cholesterol, with more aggressive targets for patients at the highest risk. Similar to the level of < 100 mg/dL for LDL cholesterol, the goal of < 120/80 in high-risk hypertensives makes sense and should be followed by all physicians who treat patients with HBP.
2. The emphasis that systolic BP is the most important target, in spite of previous teaching that treatment of diastolic hypertension is the gold standard. Most of the morbidity and mortality from cardiovascular disease, including stroke, is related to systolic hypertension, with a wide pulse pressure with only normal or mild elevations of diastolic pressure. Health care personnel must understand that a systolic BP of 150-160 mm Hg is not benign, but actually is a hazardous level requiring therapy.
3. Polypharmacy or multiple drug combinations should be the rule rather than the exception. It is important for physicians to initiate therapy with low doses of 2 different classes of drugs or be prepared to add a second and even a third drug class to achieve optimal control, rather than pushing the doses of drugs to high and potentially toxic levels. A diuretic should always be included with ACE inhibitor or ARB therapy. The focus on risk stratification is useful and is comparable to the NCEP ATPIII guidelines for lipids. Highest-risk patients are those with established vascular disease, diabetes, metabolic syndrome, or mild renal disease (proteinuria, elevated creatinine). The target BP in all of these conditions should be the "optimal" blood pressure of < 120/80 mm Hg. Hypertension may not be the sexiest subject for cardiologists and primary care physicians, but it is truly an important condition requiring commitment and vigilance. Highly effective drugs are available, which decrease events and save lives. JNC-7 is an effective road map for those who are not yet on board.
Dr. Abrams is Professor of Medicine, Division of Cardiology, University of New Mexico, Albuquerque, NM.