- Prehypertension: systolic pressure of 120–139
mm Hg or diastolic pressure of 80–90 mm Hg.
- Stage 1 hypertension: systolic pressure of 140–159
mm Hg or diastolic pressure of 90–99 mm Hg.
- Stage 2 hypertension: systolic pressure of ≥ 160 mm Hg or
diastolic pressure of ≥ 100 mm Hg.
- Measure on three separate occasions.
- In diabetic patients, diastolic pressure > 80 mm Hg, systolic
pressure > 130 mm Hg, or both, on three separate occasions.
Hypertension is a major modifiable risk factor for cardiovascular disease that can, if untreated, result in serious morbidity and
mortality from cardiac, cerebrovascular, vascular, and renal disease.
In excess of 62 million persons in the United States are estimated
to have hypertension, and only about 70% of these individuals
are aware of their diagnosis. Of those, only a third are at their
therapeutic goal. The potential for death and disability is therefore
quite high and represents a serious public health issue. Once the
diagnosis of hypertension is made and therapy instituted, elevated
blood pressure can be lowered, reducing the risk of cardiovascular
disease in most patients. Major antihypertensive trials, in large
populations, have conclusively demonstrated that there is a direct continuous
relationship between the level of blood pressure and cardiovascular
morbidity and mortality. These studies have shown that treating
all levels of hypertension significantly decreases fatal and nonfatal
stroke, coronary events, heart failure, and chronic kidney disease
and renal failure. The wide array of antihypertensive agents is
very effective in reducing blood pressure. Despite similar blood
pressure and overall mortality reductions, the reductions in incidence
of stroke, coronary ischemic events, heart failure, and renal failure
are not the same for all classes of antihypertensive agents. The
reasons for these differences have not been totally explained and
are the topic of much speculation.
A growing body of direct and inferential evidence suggests that reduction of blood pressure should not be the only goal of antihypertensive
therapy. Therapy should also be directed toward controlling all of the patient’s modifiable cardiovascular risk factors, including dyslipidemia, smoking, obesity, physical inactivity, microalbuminuria, and diabetes mellitus.
Until recently, high blood pressure was synonymous with hypertension; now, however, data suggest that there is considerably more to hypertension than increased blood pressure. Several metabolic and functional
abnormalities have even been observed in the children of hypertensive
patients prior to blood pressure elevation that are similar to,
but of a lesser magnitude than, those found in their parents. Hypertension
is also associated with insulin resistance and glucose intolerance.
Insulin levels are consistently higher in hypertensive patients
than in normotensive persons. Hyperinsulinemia is worsened by thiazide
diuretics, especially in the presence of β-blocker
therapy. Hyperinsulinemia produces a proliferation of vascular smooth muscle
and fibrous tissue and adversely affects the serum lipid profile.
Renin and angiotensin levels are also important factors in determining both the response to therapy and the prognosis. Hypertensive patients
with high renin levels have a greater incidence of myocardial infarction
than do similar patients with lower levels. Normotensive young adults
with a family history of hypertension have been found to have thicker
left ventricular (LV) walls and alterations of LV diastolic filling
in comparison with control subjects. Although not frankly abnormal,
these latter two findings are similar to but less severe than those observed
in hypertensive patients. Renal reserve also appears diminished
in the children of hypertensive parents. LV hypertrophy, a direct
result of hypertension, is twice as prevalent in patients with prehypertension
than in normotensive persons, demonstrating target organ effects
of blood pressures that were previously thought to be normal. Hypertension,
therefore, is a multisystem disorder with involvement of the cardiovascular, neuroendocrine,
and renal systems with a strong genetic component.
Blood pressure gradually increases throughout childhood and adolescence.
The best predictor of the level of future blood pressure is the
relative level of blood pressure of a child in relation to his or
her peers. During childhood and adolescence, body weight is a major
determinant of blood pressure, with heavier children having higher
blood pressures. High blood pressure is uncommon under the age of
20; if present, it is usually associated with renal insufficiency,
renal artery stenosis, or coarctation of the aorta. The initial
presentation of high blood pressure usually occurs in the third
to the sixth decade, and blood pressure may fluctuate significantly
during the early course of the disease. The prevalence of hypertension
increases with age and is greater in men than women. In the elderly
population, the gender distribution reverses, and more women than
men have high blood pressure. More than 50% of the US population
age 60–69 years and 75% of those 70 years or older
Large epidemiologic and intervention trials have clearly defined the risks of elevations of blood pressure and the benefits of treatment.
Evidence of target organ damage has been demonstrated at lower levels
of blood pressure than was previously known. As a result, the definition
of hypertension has been revised. The new definition includes a new
classification of prehypertension, which is thought to identify
individuals at increased risk for hypertension and therefore require
closer follow-up. Everyone should be screened for the presence of
high blood pressure; testing should be done routinely in the physician’s
office or at one of the larger community screening activities.
These activities are typically targeted at those at greater risk for high blood pressure: older individuals, individuals with previously
high-normal blood pressures (prehypertension), blacks, sedentary individuals,
and those with a family history of hypertension.
Ethnic and Socioeconomic Factors
Blacks have both an earlier onset and a greater prevalence of high blood pressure than do whites, Asians, and Native Americans at all
ages. Over the age of 50 years, hypertension is prevalent in more
than 40% of black males, compared with approximately 27% in
white males. Severe high blood pressure (diastolic blood pressure