Management of Hypertension: An Overview of JNC 7
Hypertension is a common disorder that affects approximately 1 billion people and contributes to 1 in 8 deaths: it is the third leading cause of death worldwide.1 Approaches to the management of hypertension are constantly evolving and being refined on the basis of findings obtained from well-designed, adequately controlled clinical trials. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7)2 was released in May 2003. The purposes of this article are to update the previously published guidelines (JNC 6)3 and to provide an evidence-based approach for the evaluation and management of elevated blood pressure.
Changes in Classification System
Under the JNC 7 guidelines, the normal blood pressure for adults aged 18 years or older is a systolic pressure of <120 mm Hg and a diastolic pressure of <80 mm Hg. The categories of "Normal" and "High Normal" blood pressure were removed and replaced with a new category, "Prehypertension." Additionally, JNC 7 simplified the classification system by eliminating "Stage 3 Hypertension" and combining it with "Stage 2 Hypertension," because of the similarity in management. Collectively, this new and simplified classification of blood pressure (Table 1) reflects the recognition of the value of early detection and the need for aggressive management, particularly in patients with comorbid conditions and those in Stage 2 Hypertension.
Changes in Approach to Treatment
JNC 7 sets a novel approach to the management of hypertension with emphasis on patients classified as prehypertensives. Such individuals are at increased risk for the development of hypertension and, therefore, should be encouraged to undergo lifestyle modification as well as frequent monitoring. Nonetheless, in the presence of compelling indications (eg, diabetes mellitus or kidney disease), prehypertensive patients should receive pharmacologic agents that have been proven beneficial in such comorbidities: for example, angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs).
In addition to lifestyle modification, patients who fall into Stage 1 Hypertension should receive drug therapy??preferably with a thiazide-type diuretic. Lastly, patients in Stage 2 Hypertension require more aggressive management. Such patients should be initiated on 2 antihypertensive agents, one of them a thiazide-type diuretic.
Based on the changes in classification, the approach to the management of hypertension also is simplified (Figure). The treatment approach is determined based on the classification of blood pressure, the presence of compelling indications, and the stage of hypertension.
Increase in Hypertension Risk with Age
According to the results of the Framingham Heart Study,4 people who are normotensive by age 55 have a 90% lifetime risk for the development of hypertension. With rapid advances in medical therapies, patients are living longer. Hence, nearly all individuals will eventually require antihypertensive drug therapy. Early detection and prevention will result in better outcomes.
Systolic Blood Pressure
Isolated systolic hypertension (ISH) affects approximately half of people >60 years.5 Although it was once considered a part of the aging process, current data suggest that ISH confers a substantial cardiovascular (CV) risk in patients over the age of 50.6,7 Furthermore, it has been shown that ISH is a significant predictor of CV risk, more so than diastolic blood pressure.8,9 Therefore, ISH is not a benign condition and should not be ignored.
Prevention and Lifestyle Modification
Small elevations in blood pressure result in a significant increase in CV risk: the risk of CV disease doubles with each increment of 20/10 mm Hg above 115/75 mm Hg.10 Thus, health-promoting lifestyle modification should be recommended to all patients, and more so for those classified as prehypertensives. Components of lifestyle modification, which have demonstrated effectiveness in reducing blood pressure, include the following:
- Weight reduction in patients who are obese to achieve a body mass index of 18.5 to 24.9
- A decrease in daily sodium intake to ??2.4 g
- Regular aerobic physical activity of 30 minutes daily on most days of the week
- Moderation of alcohol consumption
Additionally, patients should be encouraged to adopt the Dietary Approaches to Stop Hypertension (DASH) plan.11 Such a diet is rich in fruits, vegetables, and low-fat dairy products, with reduced content of total and saturated fat. This diet has been shown to be beneficial in reducing elevated blood pressure levels, particularly when combined with low sodium intake.12 Lastly, patients who smoke should be directed to smoking-cessation programs.
Selecting the most appropriate drug class depends not only on the patient's blood pressure, but also on the presence of compelling indications. JNC 7 recommends that patients meeting the criteria for drug therapy be started on thiazide-type diuretics, either alone or in combination with a drug from one of the other drug classes: ACEIs, ARBs, beta-blockers (BBs), or calcium channel blockers (CCBs). The beneficial effects of thiazides are supported by data obtained from the ALLHAT trial,13 the largest trial ever dealing with hypertension. Thiazide diuretics appear to be as effective as other antihypertensive agents. In addition, they are the most cost-effective antihypertensives to date.
JNC 7 provides a blueprint for the management of hypertension in select populations, such as the elderly and people with certain racial backgrounds, as well as patients with comorbid conditions. Drug treatment should be individualized. Drug selection is supported by clinical trials documenting efficacy and favorable outcomes. Other considerations include the patient's past and current medication history, cost, and tolerability. Table 2 includes a list of compelling indications with first-line and alternative treatment options.
Hypertension and Angina Pectoris
JNC 7 recommends BBs or long-acting CCBs as first-line agents. Patients with acute coronary syndrome (unstable angina or myocardial infarction) should be initiated on BBs and ACEIs. After myocardial infarction, BBs, ACEIs, and aldosterone antagonists have been shown to be beneficial.
Hypertension and Heart Failure
ACEIs and BBs should be instituted in hypertensive patients with asymptomatic heart failure. Recent data suggest that patients with symptomatic ventricular dysfunction or end-stage heart disease also would benefit from other agents such as BBs, ARBs, and aldosterone antagonists. In cases of inadequate blood pressure control, the long-acting CCB amlodipine provides a safe option for the hypertensive patient with heart failure.14
Hypertension and Diabetes Mellitus
JNC 7 suggests thiazide-type diuretics, BBs, ACEIs, ARBs, and CCBs for patients with hypertension and diabetes mellitus. These agents have shown benefit in reducing the incidence of CV disease and stroke in diabetic patients.
Hypertension and Renal Disease
JNC 7 recommends that patients with hypertension and renal disease receive ACEIs or ARBs. Dose-related biochemical adverse effects, such as an increase in serum creatinine (~35% above baseline) or mild hyperkalemia, should not limit the use of these agents. Nonetheless, patients should be closely monitored. Often, a minimum of 2 to 3 agents is needed to control blood pressure in patients with renal disease. A combination including a diuretic is beneficial. Optimal doses of loop diuretics should be considered.
Hypertension and Cerebrovascular Disease
A combination of an ACEI and a thiazide-type diuretic is given a firm recommendation for reducing stroke rates. Nonetheless, the benefits of acute lowering of blood pressure during stroke are still unclear.
Hypertension is among the most commonly encountered disorders in the ambulatory setting. The guidelines from the JNC 7 are practical and easily applied to hypertensive patients. Compliance with the guidelines will result in improved patient outcomes.
Dr. Balbisi is an assistant clinical professor at St. John's University, College of Pharmacy & Allied Health Professions, and clinical coordinator of ambulatory medicine at Queens Hospital Center, Jamaica, NY.
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