As of 2005 data, at least 73.6 million people older than 20 years in the United States have hypertension, defined as systolic blood pressure greater than or equal to 140 mm Hg or diastolic blood pressure greater than or equal to 90 mm Hg, or both. This translates to one in four adults and more than half of those older than 60 years of age. The incidence of hypertension increases with age. If an individual is normotensive at age 55, the lifetime risk for hypertension is 90%. High blood pressure resulted in the death of 57,356 Americans in 2005. From 1995 to 2005, the death rate from hypertension rose 25.2% and the actual number of deaths rose 56.4%. Of persons with high blood pressure, 78.7% are aware of their diagnosis. Of this group, 69% are under treatment, 45% are well controlled, and 55% are not. Hypertension is most prevalent among the black population, affecting one of every three African Americans. Non-Hispanic blacks and Mexican Americans are also more likely to suffer from high blood pressure than non-Hispanic whites.
The National High Blood Pressure Education Program (NHBPEP), which is coordinated by the National Heart, Lung, and Blood Institute (NHBLI) of the National Institutes of Health, was established in 1972. The program was designed to increase awareness, prevention, treatment, and control of hypertension. Data from the National Health and Nutrition Examination Survey (NHANES), conducted between 1976 and 2000, revealed that of patients aware of their high blood pressure and under treatment, the number who had achieved control of their high blood pressure had increased (Table 34-1). Coincident with these positive changes was a dramatic reduction in morbidity and mortality (40%-60%), including stroke and myocardial infarction (MI) secondary to hypertension. However, the most recent NHANES III survey, conducted in 1999-2000, showed a leveling off of improvement.
|II (1976-1980)||III (Phase 1, 1988-1991)||III (Phase 2, 1991-1994)||1999-2000|
High blood pressure is easily detected and usually controlled with appropriate intervention. Of the patients with high blood pressure, 78.7% are aware of their diagnosis. Among this group, 69% are under treatment, 45% are well controlled, and 55% are not. In addition, the incidence of end-stage renal disease and the prevalence of heart failure continue to increase. Both conditions have been linked to uncontrolled hypertension.
In 2003, the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VII) was released. It provided updated recommendations based on recent studies, including more concise clinical guidelines and a simplified blood pressure classification (Table 34-2). The eighth edition is anticipated to be released in Fall of 2011.
|Initial Drug Therapy|
|BP Classification||SBPa (mm Hg)||DBPa (mm Hg)||Lifestyle Modification||Without Compelling Indication||With Compelling Indication (see Table 34-5)|
|Normal||< 120||and < 80||Encourage||No antihypertensive drug indicated||Drug(s) for compellingindicationsb|
|Stage 1 hypertension||140-159||or 90-99||Yes||Thiazide-type diuretics for most; may consider ACE inhibitor, ARB, β-blocker, calcium channel blocker, or combination||Drug(s) for compellingindicationsc; other antihypertensive drugs (diuretics, ACE inhibitors,β-blockers, calcium channel blockers) as needed|
|Stage 2 hypertension||≥160||or ≥100||Yes||Two-drug combination for mostc (usuallythiazide-type diuretic and ACE inhibitor or ARB or β-blocker or calcium channel blocker)|
In 90%-95% of cases of hypertension, no cause can be identified. A role for genetics has been implicated in the development of high blood pressure (eg, hypertension is more prevalent in some families and in African Americans). Additional risk factors include increased salt intake, excess alcohol intake, obesity, sedentary lifestyle, and certain personality traits, including aggressiveness and poor stress coping skills.
In only 5% of cases can a cause for hypertension be found; however, it is reasonable to look for an underlying cause in patients diagnosed with hypertension. History or physical examination may suggest an underlying etiology, or the first clue may come later when patients fail to respond appropriately to standard drug therapy. In addition, secondary hypertension should be considered in those with sudden onset of hypertension; in those with suddenly uncontrolled blood pressure that had previously been well controlled; and in patients younger than 30 years of age without a family history of hypertension.
Etiologies of secondary hypertension that must be considered in the appropriate patient include use of certain medications such as oral contraceptives, sympathomimetics, decongestants, nonsteroidal anti-inflammatory drugs, appetite suppressants, antidepressants, adrenal steroids, cyclosporine, and erythropoietin. All of these medications can contribute to an elevation in blood pressure. Hypertension can also be related to excessive use of caffeine, ingestion of licorice, or use of illicit drugs such as cocaine or amphetamines.
Hypertension can also occur secondary to acute and chronic kidney disease, which might be suggested by a flank mass, elevated creatinine level, or abnormal findings such as proteinuria, hematuria, or casts on routine urinalysis. Rarely, hypertension may be related to renal artery stenosis, particularly if onset is before the age of 20 or after the age of 50 years. Abdominal bruits with radiation to the renal area may be heard. Other causes to consider in the differential diagnosis include hypo- or hyperthyroidism, primary hyperaldosteronism, Cushing syndrome, coarctation of the aorta, pheochromocytoma, and sleep apnea syndrome in the appropriate clinical presentation. When such causes are entertained, appropriate evaluation should be undertaken.
A healthy lifestyle is hailed both as prevention and as initial therapy for hypertension (Table 34-3). Clinical trials assessing both prevention (Trials of Hypertension Prevention—Phase II, TONE) and nonpharmacologic treatment of mild hypertension (TOMHS, DASH, low-sodium DASH, PREMIER) support the positive impact of maintaining optimal weight, a regular aerobic exercise program, and a diet low in sodium, saturated fat, and total fats and rich in fruits and vegetables. Excessive alcohol intake should be reduced and smoking cessation encouraged.
|Modification||Recommendationb||Approximate SBP Reduction (range)|
|Weight reduction||Maintain normal body weight (BMI 18.5-24.9 kg/m2)||5-20 mm Hg/10 kg weight loss|
|Adopt DASH eating plan||Consume a diet rich in fruits, vegetables, and low-fat dairy products with a reduced content of saturated and total fat||8-14 mm Hg|
|Dietary sodium reduction||Reduce dietary sodium intake to no more than 100 mmol/d (2.4 g sodium or 6 g sodium chloride)||2-8 mm Hg|
|Physical activity||Engage in regular aerobic physical activity such as brisk walking (at least 30 min/d, most days of the week)||4-9 mm Hg|
|Moderation of alcohol consumption||Limit consumption to no more than 2 drinks (1 oz or 30 mL ethanol; eg, 24 oz beer, 10-oz wine, or 3 oz 80-proof whiskey) per day in most men and to no more than 1 drink per day in women and lighter weight persons||2-4 mm Hg|
Before patients with hypertension can be offered adequate treatment, they must be properly diagnosed. Because patients are often asymptomatic, the risk factors for hypertension must be understood and appropriate patients screened. In addition to the modifiable risk factors noted earlier, there are nonmodifiable factors, including African-American race, family history of hypertension, and increasing age.
There are usually no physical findings early in the course of hypertension. In some patients, the presence of hypertension may be signaled by early morning headaches or, in those with severe hypertension, by signs or symptoms associated with target organ damage. Such symptoms might include nausea, vomiting, visual disturbance, chest pain, or confusion. More typically, the first indication is an elevated blood pressure measurement taken with a sphygmomanometer during a routine visit to a medical provider or after the patient has had a stroke or MI.
For proper measurement of blood pressure, the patient should be seated in a chair with his or her back supported and the arm bared and supported at heart level. Caffeine and tobacco should be avoided in the 30 minutes preceding measurement, and measurement should begin after 5 minutes of rest. The cuff size should be appropriate for the patient’s arm, defined by a cuff bladder that encircles 80% of the arm. It is important that the diagnosis be made after the elevation of blood pressure is documented with three separate readings, on three different occasions, unless the elevation is severe or is associated with symptoms requiring immediate attention (hypertensive urgency or emergency). Transient elevation of blood pressure secondary to pain or anxiety, as experienced by some patients when they enter a physician’s office (“white coat syndrome”), does not require treatment. In cases in which the diagnosis is in question, properly taken home blood pressure measurements can be useful.
A goal of JNC VII was to simplify blood pressure classification when making the diagnosis of hypertension (see Table 34-2). A new category, designated prehypertension, was added, and stages 2 and 3 from JNC VI were combined to form a single category (stage 2). These classifications are based on the average of two or more provider-obtained blood pressure measurements from a seated patient.
Patients should be encouraged to do self-monitoring of their blood pressure at home. Many easy-to-use blood pressure monitors are commercially available at reasonable cost for use at home. Validated electronic devices are recommended, and independent reviews of available devices, such as that published by Consumer Reports, are available to assist the consumer. These devices should be periodically checked for accuracy. Self-measurement can be helpful, not only in establishing the diagnosis of hypertension, but also in assessing response to medical therapy, and in encouraging patient compliance with therapy by providing regular feedback on therapy response.
Patients with documented hypertension must undergo a thorough evaluation that includes objectives advanced by JNC VII: assessment of lifestyle and identification of cardiovascular risk factors, identification of comorbidities that would guide therapy, and surveillance for identifiable causes of high blood pressure and to establish whether the patient already manifests evidence of target end-organ damage.
A thorough history should be obtained. Any prior history of hypertension should be elicited as well as response and side effects to any previous hypertension therapy. It is important to inquire about any history or symptoms suggestive of coronary artery disease or other significant comorbidities, including diabetes mellitus, heart failure, dyslipidemia, renal disease, and peripheral vascular disease. The family history should also be reviewed, with special attention to the presence of hypertension, premature coronary artery disease, diabetes, renal disease, dyslipidemia, or stroke. Use of tobacco, alcohol, or illicit drugs should be documented, as well as dietary intake of sodium, saturated fat, and caffeine. Recent changes in weight and exercise level should be queried. Current medications used by the patient should be reviewed, including over-the-counter medications and herbal formulations.