Screening for Hypertension

 
Recommendation:
 
Blood pressure should be measured regularly in all persons 
aged 3 and above (see Clinical Intervention).
 
Burden of Suffering
 
Hypertension may occur in as many as 58 million Americans.1 
It is a leading risk factor for coronary artery disease, 
congestive heart failure, stroke, renal disease, and 
retinopathy. These complications of hypertension are among 
the most common and serious diseases in the United States, 
and successful efforts to lower blood pressure could thus 
have substantial impact on population morbidity and 
mortality. Heart disease is the leading cause of death in 
the United States, accounting for over 765,000 deaths each 
year, and cerebrovascular disease, the third leading cause 
of death, accounts for 150,000 deaths each year.2 
Hypertension is more common in blacks and the elderly.1
 
Efficacy of Screening Tests
 
The most accurate devices for measuring blood pressure 
(e.g., intraarterial catheters) are not appropriate for 
routine screening because of their invasiveness, technical 
limitations, and cost. Office sphygmomanometry (the blood 
pressure cuff) remains the most appropriate screening test 
for hypertension in the asymptomatic population. Although 
this test is highly accurate when performed correctly, 
false-positive and false-negative results (i.e., recording 
a blood pressure that is not representative of the 
patient's mean blood pressure) do occur in clinical 
practice.3 A recent study found that 21% of persons 
diagnosed as mildly hypertensive based on office 
sphygmomanometry had no evidence of hypertension when 
24-hour ambulatory recordings were obtained.4
 
Errors in measuring blood pressure may result from 
instrument, observer, and/or patient factors.5 Examples of 
instrument error include manometer dysfunction, pressure 
leaks, stethoscope defects, and bladders of incorrect width 
and length for the patient's arm size. The observer can 
introduce errors due to sensory impairment (difficulty 
hearing Korotkoff sounds or reading the manometer), 
inattention, inconsistency in recording Korotkoff sounds 
(e.g., Phase IV vs. Phase V), and subconscious bias (e.g., 
digit preference'' for numbers ending with zero or 
preconceived notions of normal'' pressures). The patient 
can be the source of misleading readings due to posture and 
biological factors. Posture (i.e., lying, standing, 
sitting) and arm position in relation to the heart can 
affect results by as much as 10 mm Hg.5 Biological factors 
include anxiety, meals, tobacco, temperature changes, 
exertion, and pain. Due to these limitations in the 
test-retest reliability of blood pressure measurement, it 
is commonly recommended that hypertension be diagnosed only 
after more than one elevated reading is obtained on each of 
three separate visits.1
 
Additional factors affect accuracy when performing 
sphygmomanometry on children; these difficulties are 
especially common when testing infants and toddlers under 
age 3.6 First, there is increased variation in arm 
circumference, requiring greater care in the selection of 
cuff sizes. Second, the examination is more frequently 
complicated by the anxiety and restlessness of the patient. 
Third, the disappearance of Korotkoff sounds (Phase V) is 
often difficult to hear in children and Phase IV values are 
often substituted. Fourth, erroneous Korotkoff sounds can 
be produced inadvertently by the pressure of the 
stethoscope diaphragm against the antecubital fossa. 
Finally, the definition of pediatric hypertension has 
itself been uncertain because of confusion over normal 
values during childhood. Previous criteria using population 
data to define the 95th percentile at different ages were 
erroneously high.7 Revised criteria for pediatric 
hypertension, based on data from over 70,000 children, have 
recently been published6 (see Clinical Intervention).
 
Effectiveness of Early Detection
 
There is a direct relationship between the magnitude of 
blood pressure elevation and the benefit of lowering 
pressure. In persons with malignant hypertension, the 
benefits of intervention are most dramatic; treatment 
increases five-year survival from near zero (data from 
historical controls) to 75%.8 The efficacy of treating 
moderate hypertension (diastolic blood pressure above 104 
mm Hg) is also clear, as demonstrated in the Veterans 
Administration Cooperative Study on Antihypertensive 
Agents.9-11 In this randomized double-blind controlled 
trial, middle-aged men with diastolic blood pressure above 
104 mm Hg experienced a significant reduction in 
cardiovascular events after treatment with antihypertensive 
medication. 

Persons with mild hypertension (diastolic blood pressure of 
90-104 mm Hg) also benefit from treatment. This was 
confirmed in the Hypertension Detection and Follow-Up 
Program, a randomized controlled trial involving nearly 
11,000 hypertensives.12 The intervention group received 
standardized pharmacologic treatment (stepped care'') while 
the control group was referred for community medical care. 
There was a statistically significant 17% reduction in 
five-year all-cause mortality in the group receiving 
standardized drug therapy; the subset with mild 
hypertension experienced a 20% reduction in mortality.12 
Deaths due to cerebrovascular disease, ischemic heart 
disease, and other causes were also significantly reduced 
in the stepped care group.13 Similar results have been 
reported in other studies, such as the Australian National 
Blood Pressure Study14 and the Medical Research Council 
trial.15 Although treatment of hypertension is associated 
with multiple benefits, the greatest effect appears to be 
in the prevention of cerebrovascular disease.16 Improved 
treatment of high blood pressure has been credited with the 
greater than 50% reduction in age-adjusted stroke mortality 
that has been observed since 1972.1,17
 
Although the efficacy of antihypertensive treatment has 
been well established in clinical research, certain factors 
may influence the magnitude of benefit achieved in actual 
practice. First, the benefits of treatment may be less 
significant or less well proven in certain population 
groups, such as children. Second, nonpharmacologic 
first-line therapy (e.g., weight reduction, exercise, 
sodium restriction, decreased alcohol intake) may be less 
effective than drug therapy in achieving significant and 
consistent blood pressure reductions. Although it is known 
that weight reduction and sodium restriction can lower 
blood pressure,18,19 the magnitude and duration of 
reduction in actual practice may be limited by biological 
factors (e.g., hypertensives who are not salt-sensitive'') 
and the difficulties of maintaining behavioral changes 
(e.g., weight loss). Finally, compliance with drug therapy 
may be limited by the inconvenience, side effects, and cost 
of these agents.20,21
 
Recommendations of Others
 
Revised recommendations for adults from the National Heart, 
Lung, and Blood Institute were issued recently by the Joint 
National Committee on Detection, Evaluation, and Treatment 
of High Blood Pressure,1 and similar recommendations have 
been issued by the American Heart Association.22 These call 
for routine blood pressure measurement at least once every 
two years for persons with a diastolic blood pressure below 
85 mm Hg and a systolic pressure below 140 mm Hg. 
Measurements are recommended annually for persons with a 
diastolic blood pressure of 85-89 mm Hg. Persons with 
higher blood pressures require more frequent measurements. 
The Canadian Task Force recommends that all persons aged 25 
and over receive a blood pressure measurement during any 
visit to a physician.23 The American Academy of Pediatrics 
and the National Heart, Lung, and Blood Institute recommend 
that children and adolescents receive annual blood pressure 
measurements from ages 3-20.6
 
Discussion
 
It is clear from several large clinical trials that 
lowering blood pressure is beneficial and that the 
population incidence of several leading causes of death can 
be reduced through the detection and treatment of high 
blood pressure. An average diastolic blood pressure 
reduction of 6-8 mm Hg across the population could reduce 
the incidence of coronary artery disease by 25% and the 
incidence of strokes by 50%.24 At the same time, it is 
important for clinicians to minimize the potential harmful 
effects of detection and treatment. For example, if 
performed incorrectly, sphygmomanometry can produce 
misleading results. Some hypertensive patients thereby 
escape detection (false negatives) and some normotensive 
persons receive inappropriate labeling (false positives), 
which may have certain psychological, behavioral, and even 
financial consequences.25 Treatment of hypertension can 
also be harmful as a result of medical complications, 
especially related to drugs. Clinicians can minimize these 
effects by using proper technique when performing 
sphygmomanometry, making appropriate use of 
nonpharmacologic methods, and prescribing antihypertensive 
drugs with careful adherence to current guidelines.
 
Clinical Intervention
 
Blood pressure should be measured regularly in all persons 
aged 3 and above. The optimal interval for blood pressure 
screening has not been determined and is left to clinical 
discretion. Current expert opinion is that persons thought 
to be normotensive should receive blood pressure 
measurements at least once every two years if their last 
diastolic and systolic blood pressure readings were below 
85 mm Hg and 140 mm Hg, respectively, and annually if the 
last diastolic blood pressure was 85-89 mm Hg.1 
Sphygmomanometry should be performed in accordance with 
recommended technique.*1 Hypertension should not be 
diagnosed on the basis of a single measurement; elevated 
readings** should be confirmed on more than one reading at 
each of three separate visits. Once confirmed, patients 
should receive counseling regarding exercise (see Chapter 
49), weight reduction, dietary sodium intake (Chapter 50), 
and alcohol consumption (Chapter 47).1 Other cardiovascular 
risk factors, such as smoking and elevated serum 
cholesterol, should also be discussed (Chapters 2 and 48). 
Antihypertensive drugs should be prescribed in accordance 
with recent guidelines1 and with attention to current 
techniques for improving compliance.20,21
 
Notes
 
*Guidelines for Sphygmomanometry
 
  Patient should be seated with arm bared, supported, and 
positioned at heart level.
 
  Patient should have refrained from smoking or ingesting 
caffeine within 30 minutes before measurement.
 
  Measurement should begin after five minutes of quiet 
rest.
 
  An appropriate cuff size (child, adult, large adult) 
should be selected; the rubber bladder should encircle at 
least two thirds of the arm.
 
  Measurements should be taken with a mercury 
sphygmomanometer, a recently calibrated aneroid manometer, 
or a validated electronic device.
 
  Both systolic and diastolic pressures should be recorded; 
the disappearance of sound (Phase V) indicates the 
diastolic pressure.
 
  Two or more readings should be averaged; if the first two 
differ by more than 5 mm Hg, additional readings should be 
obtained.
 

**In adults, current blood pressure criteria for the 
diagnosis are a diastolic pressure of 90 mm Hg or greater 
or a systolic pressure of 140 mm Hg or greater.1()  In 
children, the criteria vary with age:6
 
Pediatric Blood Pressure
 
Age (Yrs)  Diastolic (mm Hg)  Systolic (mm Hg)
 
0-2    	   74		    	   112
 3-5    	   76		    	   116
 6-9    	   78		    	   122
 10-12  	   82		    	   126
 13-15  	   86		    	   136
 
References
 
1.
 
1988 Joint National Committee. The 1988 report of the Joint 
National Committee on Detection, Evaluation, and Treatment 
of High Blood Pressure. Arch Intern Med 1988; 148:1023-38.
 
2. National Center for Health Statistics. Advance report of 
final mortality statistics, 1986. Monthly Vital Statistics 
Report [Suppl], vol. 37, no. 6. Hyattsville, Md.: Public 
Health Service, 1988. (Publication no. DHHS (PHS) 
88-1120.)
 
3.
 
Tifft CP. Are the days of the sphygmomanometer past? Arch 
Intern Med 1988; 148:518-9.
 
4.
 
Pickering TG, James GD, Boddie C, et al. How common is 
white coat hypertension? JAMA 1988; 259:225-8.
 
5.
 
Kirkendall WM, Feinleib M, Freis ED, et al. Recommendations 
for human blood pressure determination by 
sphygmomanometers. Subcommittee of the AHA Postgraduate 
Education Committee. Circulation 1980; 62:1146A-55A.
 
6.
 
Task Force on Blood Pressure Control in Children. Report of 
the Second Task Force on Blood Pressure Control in 
Children--1987. Pediatrics 1987; 79:1-25.
 
7.
 
Mehta SK. Pediatric hypertension: a challenge for 
pediatricians. Am J Dis Child 1987; 141:893-4.
 
8.
 
Hansson L. Current and future strategies in the treatment 
of hypertension. Am J Cardiol 1988; 61:2C-7C.
 
9.
 
Veterans Administration Cooperative Study Group on 
Antihypertensive Agents. Effects of treatment on morbidity 
in hypertension. III. Influence of age, diastolic pressure, 
and prior cardiovascular disease: further analysis of side 
effects. Circulation 1972; 45:991-1004.
 
10.
 
Idem. Effects of treatment on morbidity in hypertension: 
results in patients with diastolic pressures averaging 115 
through 129 mm Hg. JAMA 1967; 202:1028-34.
 
11.
 
Idem. Effects of treatment on morbidity in hypertension. 
II. Results in patients with diastolic pressures averaging 
90 through 114 mm Hg. JAMA 1970; 213:1143-52. 12.
 
Hypertension Detection and Follow-Up Program Cooperative 
Group. Five-year findings of the Hypertension Detection and 
Follow-Up Program. I. Reduction in mortality of persons 
with high blood pressure, including mild hypertension. JAMA 
1979; 242:Idem. Persistence of reduction in blood pressure 
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and Follow-Up Program. JAMA 1988; 259:2113-22.
 
14.
 
Management Committee of the Australian National Blood 
Pressure Study. The Australian therapeutic trial in mild 
hypertension. Lancet 1980; 1:1261-7.
 
15.
 
Medical Research Council Working Party. MRC trial of 
treatment of mild hypertension: principal results. Br Med J 
1985; 291:97-104.
 
16.
 
MacMahon SW, Cutler JA, Furberg CD, et al. The effects of 
drug treatment for hypertension on morbidity and mortality 
from cardiovascular disease: a review of randomized, 
controlled trials. Prog Cardiovasc Dis [Suppl] 1986; 
29:99-118. and the declining incidence of stroke. JAMA 
1987; 258:214-7.
 
17.
 
Garraway WM, Whisnant JP. The changing pattern of 
hypertension and the declining incidence of stroke. JAMA 
1987; 258:214-7.
 
18.
 
Nonpharmacological approaches to the control of high blood 
pressure. Final report of the Subcommittee on 
Nonpharmacological Therapy of the 1984 Joint National 
Committee on Detection, Evaluation, and Treatment of High 
Blood Pressure. Hypertension 1986; 8:444-67.
 
19.
 
Stamler J, Stamler R. Intervention for the prevention and 
control of hypertension and atherosclerotic diseases: 
United States and international experience. Am J Med 1984; 
76:13-36.
 
20.
 
McClellan WM, Hall WD, Brogan D, et al. Continuity of care 
in hypertension: an important correlate of blood pressure 
control among aware hypertensives. Arch Intern Med 1988; 
148:525-8.
 
21.
 
National Institutes of Health. The physician's guide: 
improving adherence among hypertensive patients. Working 
Group on Health Education and High Blood Pressure Control. 
Bethesda, Md.: Department of Health and Human Services, 
1987.
 
22.
 
Grundy SM, Greenland P, Herd A, et al. Cardiovascular and 
risk factor evaluation of healthy American adults. A 
statement for physicians by an ad hoc committee appointed 
by the Steering Committee, American Heart Association. 
Circulation 1987; 75:1340A-62A.
 
23.
 
Canadian Task Force on the Periodic Health Examination. 
1984 update. Can Med Assoc J 1984; 130:2-15.
 
24.
 
Blackburn H. Public policy and dietary recommendations to 
reduce the population level of blood cholesterol. Am J Prev 
Med 1985; 1:3-11.
 
25.
 
MacDonald LA, Sackett DL, Haynes RB, et al. Labelling in 
hypertension: a review of the behavioral and psychological 
consequences. J Chron Dis 1984; 37:933-42.
 


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