CTF Structured Abstract: Screening for Hypertension in Adults

Canadian Task Force on Preventive Health Care

Structured Abstract

Please note: In 2003, the CTF updated its Grades of Recommendations to include an "I Recommendation" for situations where insufficient evidence exists to allow a recommendation to be made. (Formerly, these situations were captured under a "C Recommendation".) This change is not retroactive, and all "C Recommendations" made prior to 2003 have not been reevaluated in light of the new "I" recommendation grade. For a discussion of these recommendation grades, please link to the 2003 article in the Canadian Medical Association Journal here.

Screening for Hypertension in Young and Middle-Aged Adults

Prepared by Alexander G. Logan, MD, FRCPC, Professor of Medicine, University of Toronto, Ontario

These recommendations were finalized by the Task Force in March 1994

Objective
Burden of Suffering
Options
Outcomes

Evidence
Values
Benefits, Harms, and Costs
Recommendations

Validation
Sponsors
Selected References

Objective

To make recommendations for the screening and treatment of hypertension in young and middle aged adults in Canada.

Burden of Suffering

Estimates from several BP surveys over the past decade suggest that up to 15% of the adult population have definite or established hypertension and that an almost equal percentage have labile hypertension characterized by elevations of BP on some, but not all, occasions. Epidemiological and actuarial studies have repeatedly demonstrated that cardiovascular morbidity and mortality are substantially higher in hypertensives, compared with normotensives at all ages and in both sexes. Because hypertension is an important contributor to the principal cardiovascular diseases which account for more than 40% of all deaths in Canada, good BP control will have a major beneficial effect on health care costs. Hypertension is a major contributor to pressure-related events such as stroke, congestive heart failure and ruptured aortic aneurysm, and a significant risk factor for atheromatous complications such as coronary heart disease and occlusive peripheral arterial disease. The absolute risk of cardiovascular disease amongst equally hypertensive individuals varies substantially, depending upon a history of previous cardiovascular disease or the presence of associated risk factors including hypercholesterolemia, cigarette smoking, glucose intolerance, left ventricular hypertrophy, older age, and male gender.

Options

Blood pressure measurement is usually done by health professionals using mercury sphygmomanometers or by self monitoring. Nondrug treatment of hypertension can include dietary interventions, weight reductions, reduction of alcohol consumption, increased physical activity, and sodium restrictions. Drug treatment of hypertension includes diuretics, b -adrenergic blockers, calcium entry blockers, angiotensin converting enzyme and receptor blockers, and alpha-adrenergic blockers. Drugs that are no longer prescribed are reserpine, alpha-methyldopa, guanethidine, hydralazine, and clonidine. Drugs that have insufficient data on long-term benefits and risks for consideration in this guideline are calcium entry blockers, angiotensin converting enzyme inhibitors, and alpha-adrenergic blockers.

Outcomes

Treatment outcomes include reduced blood pressure, decreased cardiovascular events and stroke, and decreased mortality (all cause, cardiac, and noncardiac).

Evidence

MEDLINE was searched for 1966 to March 1994 using the keyword hypertension with the subheadings complications, diagnosis, drug therapy, epidemiology, prevention and control, and therapy and for 1984 to 1994 for review articles on the topic. Bibliographies were also checked for relevant studies.

Recommendations were graded as:

A Good evidence to support the recommendation that the condition be specifically considered in a PHE.

B Fair evidence to support the recommendation that the condition be specifically considered in a PHE.

C Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds.

D Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

E Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

Quality of evidence was rated according to 5 levels:

I Evidence from at least 1 properly randomized controlled trial (RCT).

II-1 Evidence from well-designed controlled trials without randomization.

II-2 Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.

II-3 Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.

III Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.

Values

The 13-member Task Force of experts in family medicine, geriatric medicine, pediatrics, psychiatry and epidemiology used an evidence-based method for evaluating the effectiveness of preventive health care interventions. Recommendations were not based on cost-effectiveness of options. Patient preferences were not discussed.

Background papers providing critical appraisal of the evidence and tentative recommendations prepared by the chapter author were pre-circulated to the members. Evidence for this topic was presented and deliberated upon in 1- to 2-day meetings, 2 to 3 times per year from January 1993 to June 1993. Consensus was reached on final recommendations.

Benefits, Harms, and Costs

The mercury sphygmomanometer is an accurate and dependable instrument for detection of hypertension and is usually considered to be the standard for measurement of blood pressure. Two or more readings should be averaged. The primary definition of hypertension is diastolic blood pressure below above 90 mmHg although in some situations such as renal disease in patients with diabetes this minimum should be lower.

Nondrug therapies (weight reduction in overweight persons, moderation in alcohol consumption, increased physical activity, and sodium restriction) reduced blood pressure in short-term studies but no data exist to show reductions in cardiovascular mortality or morbidity. Despite the absence of evidence on long-term safety, acceptability and effectiveness of nondrug therapies, they are considered a useful starting point for treatment or important adjunct to drug therapy.

Young and middle aged patients (age 21 to 64 years) with diastolic blood pressure ł 90 mm Hg benefit from drug therapy. High-risk patients benefit from drug therapy and low-risk patients can start with nondrug treatments.

Meta-analyses of drug therapy show that a reduction of stroke mortality in elevated diastolic blood pressure results in a 42% reduction in fatal and non-fatal strokes (95% CI 33% to 50%) and a 14% reduction in coronary heart disease (CI 4% to 22%).

Side effects of medication are substantial and in 1 trial 20% of participants in the active treatment group had stopped medication by 5 years.

Young and middle aged patients (age 21 to 64 years) with diastolic blood pressure ł 90 mm Hg benefit from drug therapy. For high-risk patients, drug therapy is generally indicated right away, while low-risk patients can start with nondrug treatments, and progress to drug therapy, as needed.

Multifactorial intervention trials of primary prevention in high-risk patients generally have been disappointing.

Recommendations

Recommendation grade [A, B, C, D, E] and level of evidence [I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations in support of individual recommendations are identified in the guideline text.

Fair evidence exists to include measurement of blood pressure in the PHE of young and middle-aged adults [B, III]. Clinicians should average at least 2 readings on each of 3 occasions over a period of 6 months. Case-finding should be considered in all persons aged 21 to 64 years.
Good evidence exists to consider starting treat, using pharmacologic therapy, in persons aged 21 to 64 with diastolic pressures ł 90 mm Hg [A, I].
Insufficient evidence exists to include or exclude treatment of elevated diastolic blood pressure in persons under the age of 21 years [C, III] or persons with isolated systolic pressure ł 140 mm Hg and diastolic pressure < 90 mm Hg [C, III]. {This recommendation has been updated by the Canadian Hypertension Society based on new evidence (Reeves RA, Fodor JG, Gryfe CI, Patterson C, Spence JD. Report of the Canadian Hypertension Society Consensus Conference: 4. Hypertension in the elderly. Can Med Assoc J 1993;149: 815-20).} (R. Brian Haynes, personal communication)

Validation

This report was externally peer reviewed. This report was externally peer-reviewed. Most agencies agree on definitions of hypertension but disagree on when to start pharmacologic treatment (between 90 and 100 mm Hg for diastolic pressure). Most agencies agree that a reduction in diastolic pressure to below 90 mm Hg is an appropriate goal of treatment. Most guidelines recommend diuretics or b -blockers as initial treatment for patients with no specific contraindications. The World Health Organization/International Society of Hypertension guidelines suggest that any particular class of antihypertensive agents may be chosen. The U.S. Preventive Services Task Force recommends that blood pressure be monitored in all persons starting at 3 years of age.

Selected References

Source Document

Logan AG Screening for hypertension in young and middle-aged adults. In: Canadian Task Force on the Periodic Health Examination. Canadian Guide to Clinical Preventive Health Care. Ottawa: Health Canada, 1994; 636-48.

Other

Canadian Task Force on the Periodic Health Examination: The periodic health examination: 2. 1984 update. Can Med Assoc J. 1984;130:1278-85.

Link to Full Text of this review

Link to Summary Table of Recommendations of this review

Link to Selected References list of this review

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A	Good evidence to support the recommendation that the condition be specifically considered in a PHE.
B	Fair evidence to support the recommendation that the condition be specifically considered in a PHE.
C	Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds.
D	Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.
E	Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

I	Evidence from at least 1 properly randomized controlled trial (RCT).
II-1	Evidence from well-designed controlled trials without randomization.
II-2	Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.
II-3	Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.
III	Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.