Hypertension: Beyond JNC 7

In the United States, 1 in every 3 adults, or ~65 million individuals, has hypertension.¹ Only 60% of hypertension patients are currently being treated, and only 34% have their hypertension adequately controlled.² Numerous other individuals, however, are unaware that they may have hypertension.

The most recent National Health and Nutrition Examination Survey data presented at the 2005 American Society of Hypertension scientific meeting indicate that hypertension is a growing health concern. Approximately 80% of individuals with hypertension are overweight or obese. Hypertension occurs in 46% of African Americans, 32% of Caucasians, 29% of Hispanic Americans, and 33% of other ethnic groups.¹ According to the results contained in the report entitled Health, United States 2005, prepared by the Centers for Disease Control and Prevention National Center for Health Statistics, ~50% of Americans 55 to 64 years of age have hypertension.³ The prevalence of the disease is dependent on many variables, such as age, race, and medical history.

With proper treatment and early intervention, morbidity and mortality rates can be decreased significantly. It is imperative that individuals be educated about the complications of hypertension if it is left untreated.

The disease usually is asymptomatic, and often it is not detected until target organs are affected. Many patients find out that they have hypertension during routine medical examinations. Sustained increased arterial pressure can cause damage to the blood vessels in the heart, kidneys, or brain and ultimately leads to an increased incidence of renal failure, congestive heart failure, coronary disease, and stroke.⁴

Etiology and Classification

Blood pressure is the force of blood against the arterial walls as it travels through the circulatory system. It may vary from moment to moment and is dependent on the patient's level of activity or emotional state. Hypertension is defined as consistently having a systolic blood pressure of >140 mm Hg or a diastolic blood pressure of >90 mm Hg.

A specific cause of hypertension, also known as secondary hypertension, can be determined in ~10% to 15% of all diagnosed cases. In cases where no specific cause can be found, patients are referred to as having essential hypertension.⁵ Risk factors for developing hypertension include lifestyle factors, uncontrolled variables, medical conditions, and some pharmacologic agents (Tables 1-4).⁶

In May 2003, the Seventh Report of the Joint National Committee (JNC 7) on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure established new guidelines for hypertension⁷ (Table 5).

The prehypertension category was added because there is a high probability that individuals whose blood pressure falls within this range also may suffer from myocardial or cerebral infarctions, congestive heart failure, or renal disease. Prehypertensive individuals need to be educated and informed of the risks involved so that they can take early steps in preventing cardiovascular disease.

The JNC 7 guidelines provide information regarding the management of hypertension in specific patient populations, such as the elderly and certain ethnic groups, as well as individuals with comorbid conditions (Table 6).

New Definition of Hypertension Proposed

In May 2005, just 2 years after the publication of the JNC 7 guidelines, the American Society of Hypertension proposed a new definition of hypertension. The society established the Writing Group of the American Society of Hypertension (WG-ASH) to formulate the new definition. The writers predict that expanding the definition will lead to new approaches to researching hypertension?in particular, the early stages of the condition?and maybe even to new means of treating the disease.⁸ The proposed definition would include the following⁹:

• Hypertension is a progressive cardiovascular syndrome arising from complex and interrelated etiologies.
• Early markers of the syndrome often are present before elevated blood pressure is observed. Therefore, hypertension cannot be classified solely by discrete blood pressure thresholds.
• Progression is strongly associated with functional and structural cardiac and vascular abnormalities that damage the heart, kidney, brain vasculature, and other organs and lead to premature morbidity and death.

For more information about this proposed issue, contact the American Society of Hypertension. Its Web site is www.ash-us.org.

Diagnosis

Because most individuals with hypertension do not exhibit any symptoms or feelings of malaise, they may assume that their blood pressure is normal. Occasionally, if the blood pressure reaches extreme levels, individuals may experience some symptoms, such as the following:

• Dizziness
• Diplopia
• Headache
• Shortness of breath
• Chest pain
• Abdominal pain

Treatment

Although there is no known cure for hypertension, it is treatable using various pharmacologic and nonpharmacologic measures. Therapy is dependent on the extent of the hypertension. In all cases, lifestyle modifications, such as exercise and dietary changes, are to be encouraged. In mild cases of hypertension with no risk factors, nonpharmacologic therapies can be initiated as the sole form of therapy for a period of time, at the discretion of the physician. If these therapies are not successful, then drug therapy should be implemented. In cases where risk factors (cardiovascular disease, renal disease, or diabetes) are present, drug therapy should be considered the first line of defense.

Pharmacologic Therapies

Several classes of antihypertensive agents (Table 7¹⁰) are available to treat hypertension by various mechanisms of action. Currently, agents are available as single-entity or combination formulations, which include diuretic combinations, beta-blockers and diuretics, angiotensin-converting enzyme inhibitors (ACEIs) and diuretics, angiotensin II receptor blockers (ARBs) and diuretics, and calcium channel blockers and diuretics. The choice of therapy must be tailored to meet the specific needs of each patient, taking into consideration an individual's medical history and concurrent medication profile.

Diuretics typically are the first line of therapy in the treatment of hypertension. The JNC 7 recommends that individuals who meet the criteria for the initiation of drug therapy be started on thiazide diuretics. These drugs may be used alone or in conjunction with other antihypertensive agents, such as ACEIs, ARBs, beta-blockers, or calcium channel blockers. The use of thiazide diuretics has proven to be beneficial according to the results obtained by the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial.

The Role of the Pharmacist

The pharmacist can play an indispensable role in assisting those afflicted with hypertension by educating them about the significance of being compliant with the drug therapy prescribed and the lifestyle modifications recommended by their physicians. Whereas hypertension has been known as the "silent killer," education is the key to controlling and possibly preventing this disease from taking the lives of so many individuals each year. Successful treatment of hypertension involves commitment to quality of care and dedication to maintaining a healthy lifestyle.

Ms. Terrie is a clinical pharmacy writer based in the northern Virginia area.

For More Information on Hypertension

Please visit the following Web sites:

National Heart, Lung, and Blood Institute at www.nhlbi.nih.gov

American Heart Association at www.americanheart.org

American Society of Hypertension at www.ash-us.org

For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. A. Stahl, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: astahl@ascendmedia.com.