Report of the Canadian Hypertension Society Consensus Conference
Report of the Canadian Hypertension Society Consensus Conference
Canadian Medical Association Journal 1993; 149: 815-820
[en bref]
Paper reprints of the full text may be obtained from: Dr. Richard A. Reeves, Director, Cardiovascular Clinical Research, Bristol-Myers Squibb Pharmaceutical Research Institute, PO Box 4000, Princeton, NJ 08543- 4000
© 1993 Canadian Medical Association
Hypertension is an important challenge in the medical management of elderly people (defined here as 65 years of age or older). Although many of the previous recommendations remain valid, several important clinical trials in the elderly have been completed in the interim. Isolated systolic hypertension has finally been subjected to a treatment trial. Other reasons for a 5-year update include the new information on risk factors for cardiovascular disease and their interaction with high blood pressure in the elderly, a better understanding of diagnostic problems in the elderly, newer data on treatment-related side effects and quality of life, and further comparative studies of antihypertensive agents.
Recommendation 1: Measure the blood pressure of all elderly patients seen in the office (grade D[2]).
Recommendation 2: When possible, also measure the blood pressure after the patient has been standing for 2 minutes (grade D[2]).
Recommendation 3: Only investigate secondary hypertension in patients in whom invasive intervention is possible and who either have had rapid and high elevation of blood pressure or are resistant to or intolerant of standard treatment (grade D[2]).
Stiffness of the arteries can be an important source of error in elderly patients, causing false elevation of the diastolic blood pressure measured by the cuff method (often by as much as 20 to 30 mm Hg[5,6]), but is fortunately uncommon, involving only 2% to 5% of elderly outpatients.[6,7]
Recommendation 4: For elderly patients with high blood pressure as measured with a cuff but without end-organ damage, intra-arterial measurement by an experienced physician can be useful (although it is rarely required) to rule out pseudohypertension (grade C).
Decision making about treatment
Recommendation 5: In elderly patients target-organ damage indicating a need for antihypertensive treatment includes thoracic or abdominal aortic aneurysm (grade C[2]).
Several large, well-conducted randomized controlled trials have recently been reported (Table 3, Fig. 1). These studies included relatively healthy elderly people; generalization to sicker people should take this into consideration.
Recommendation 6: People 60 years of age or more who have a systolic blood pressure of 160 mm Hg or higher should be treated for hypertension (grade A[8-13]).
Evidence from controlled trials is lacking for the management of the unusual elderly patient who has isolated diastolic hypertension : a diastolic pressure greater than 90 mm Hg but a systolic pressure less than 160 mm Hg. The conference participants generally felt that such patients should be managed according to the guidelines for younger patients with diastolic hypertension; that is, given treatment when the diastolic pressure is 100 mm Hg or lower if there is target-organ damage[14] (including target-organ damage in the elderly) (grade D recommendation). However, the evidence-based recommendation that was approved read as follows:
Recommendation 7: (a) Patients aged 60 to 80 years who have a diastolic blood pressure of 105 mm Hg or higher should be treated (grade A[9,13]); (b) individual judgement should be used for elderly patients with a diastolic blood pressure of 90 to 104 mm Hg when the systolic blood pressure is less than 160 mm Hg (grade D).
For people over the age of 80 years there is little trial evidence, especially for less healthy patients. However, in view of the high absolute risk and particularly the serious consequences of cerebrovascular accident, treatment can reasonably be advocated on the basis of the beneficial results found in patients aged 60 to 80 years.
Recommendation 8: For newly diagnosed hypertension in patients older than 80 years, investigation and therapy should be cautious and individualized (grade D).
General guidelines for treatment
Recommendation 9: Smoking cessation can be strongly recommended to decrease cardiovascular risk at any age (grade D[15]).
Elderly people are more heterogeneous than younger ones in mood, life satisfaction, intellectual performance, physiologic reserve and mobility.
Recommendation 10: Even more than chronologic age, factors such as coexisting disease and concurrent drug therapy must be considered in investigating and treating hypertension in the older patient.
Recommendation 11: The initial therapy for mild hypertension should be nonpharmacologic (grade D). (See later section on nonpharmacologic treatment.)
Nonsteroidal anti-inflammatory drugs (NSAIDs), commonly prescribed for elderly patients, will antagonize most antihypertensive drugs[16] with the possible exception of sulindac;[17] the data specifically on the elderly are sparse.
Recommendation 12: Most NSAIDs (but not low-dose acetylsalicylic acid) can increase blood pressure[16] and should be discontinued if possible (grade B).
Recommendation 13: In general, antihypertensive treatment should be continued in hypertensive patients as they age beyond 80 years (grade D).
Recommendation 14: For patients who have been normotensive for more than 1 year a trial of treatment reduction and possible discontinuation with close monitoring of blood pressure thereafter may be worth while (grade C[18]).
Drug treatment
Recommendation 15: In general, the initial drug dose in elderly patients should be half of the usual recommended dose, to be increased gradually. Patients should be observed for changes in blood pressure and the development of side effects. (This recommendation is based on level-II evidence on diuretics [19-21] and kinetic differences for calcium entry blockers.[22-24])
Recommendation 16: The number of tablets and different drugs should be kept to a minimum. During long-term treatment in the elderly once-daily preparations are preferred for optimum compliance (grade B[25]).
Recommendation 17: Since mental impairment and orthostatic hypotension are particularly common in older people, patients should be closely monitored for these conditions as possible adverse effects of antihypertensive agents (grade D).
Recommendation 18: No outcome data exist to support different treatments in elderly patients who have or do not have echocardiographic evidence of left ventricular hypertrophy or to favour therapies known to reduce the hypertrophy (grade D).
Nonpharmacologic treatment
Recommendation 19: Nonpharmacologic treatment in elderly patients can be encouraged as an adjunct to drug therapy (grade D).
Recommendation 20: The reduction of excess alcohol intake can be recommended in elderly patients by extrapolation from grade B studies in younger subjects (grade D).
The next two recommendations are made with the provisos that there be appropriate attention to the general nutritional requirements of elderly patients and a recognition that compliance may be difficult and efficacy only modest.
Recommendation 21: Restriction of dietary sodium can help to lower blood pressure in the elderly (grade B[26,27]).
Recommendation 22: Weight reduction can be recommended for obese elderly patients by extrapolation from grade B studies in younger subjects (grade D).
First-choice monotherapy
Recommendation 23: For uncomplicated hypertension without obvious contraindication or a history of previous thiazide intolerance the preferred initial therapy is thiazide diuretics[2,8,10] (grade A). Smaller doses (12.5 mg daily of hydrochlorothiazide, 12.5 mg of chlorthalidone every other day or the equivalent) should be used initially.[3] Daily maintenance doses of 12.5 to 25 mg of hydrochlorothiazide are usually effective (grade B), even in the presence of the moderately impaired renal function often seen in older people.[2] A few patients may require 50 mg of hydrochlorothiazide daily or the equivalent.
Although the topic was outside the management area and therefore not put to a vote, there was support for asking the pharmaceutical industry and the Health Protection Branch, Department of National Health and Welfare, to make available 12.5-mg tablets of hydrochlorothiazide and chlorthalidone. At present, to avoid overly large daily doses, older patients may be faced with the mechanically difficult task of splitting a large tablet or the mental challenge of remembering to take a diuretic on alternate days.
Recommendation 24: Other agents are preferable in patients who have demonstrated intolerance of low-dose diuretic therapy, coexistent carbohydrate intolerance or non-insulin- dependent diabetes mellitus and in those who have a history of gouty arthritis (grade B[3]).
Although adding a diuretic to the regimen of a hyperlipidemic patient may appear illogical, the data on the effects of so doing are reassuring. In the pilot study of the Systolic Hypertension in the Elderly Program the cholesterol level was unchanged after 1 year of low doses of chlorthalidone.[19]
Recommendation 25: Consideration should be given to agents other than thiazide diuretics in patients with clinically important pre-existing hyperlipidemia, hyponatremia, hypokalemia or hypercalcemia (grade D). Mild hyperlipidemia or hyperuricemia is not a contraindication to low-dose diuretic therapy in elderly patients.[19]
Recommendation 26: The combination of a potassium-sparing diuretic and a thiazide diuretic could be used initially[9,10,12] and should be used if evidence of potassium depletion develops (grade B). Potassium supplements are not recommended.[2]
Recommendation 27: Loop diuretics (furosemide and ethacrynic acid) are less effective antihypertensive agents and are not recommended in the absence of congestive heart failure or severe renal insufficiency (grade D[2]).
Second-choice monotherapy
The British Medical Research Council trial, the only randomized comparison of drug classes in the elderly, indicated that a ß-blocker was less effective, less well tolerated and less beneficial than a diuretic.[10] Although the Swedish Trial in Old Patients with Hypertension achieved good results, 78% of patients begun on a ß-blocker required the addition of a diuretic.[28] Conversely, only 46% of patients who were started on a diuretic required ß-blocker supplementation. The following recommendations reflect the present uncertainty about the usefulness of ß-blockers compared with the clear benefits of diuretics.
Recommendation 28: In patients in whom diuretics are contraindicated or not preferred, initial treatment with ß-blockers in small doses is recommended (grade B[9-11]). Contraindications to the use of ß-blockers include congestive heart failure, asthma or chronic obstructive pulmonary disease, second-degree or third-degree atrioventricular block and severe peripheral vascular disease.
Recommendation 29: Beta-blockers should be used as second-choice drugs for treating hypertension in the elderly because of their lower efficacy, more frequent adverse effects and less clear benefit, especially in smokers (grade A[10]). Mild to moderate peripheral vascular disease is not a contraindication for the use of ß-blockers.[29]
Recommendation 30: Beta-blocker treatment with the addition of a thiazide diuretic when the blood pressure remains uncontrolled appears to be a useful combination for reducing the chance of cerebrovascular accident (grade A[11]).
Third-choice monotherapy
Calcium entry blockers, ACE inhibitors and several other drug classes are effective and generally safe for treating hypertension in the elderly. Compared with diuretics and ß-blockers their reduced status reflects the continuing lack of demonstrable patient benefit (i.e., reductions in rates of illness and death from hypertension). A trial of calcium entry blockers for isolated systolic hypertension is under way.[30]
Recommendation 31: Calcium entry blockers should be considered when diuretics or ß-blockers are contraindicated or not tolerated (grade D). The contraindications to the use of verapamil and diltiazem include atrioventricular block and congestive heart failure. Edema or flushing with dihydropyridines and constipation with verapamil may be problematic.
ACE inhibitors reduce blood pressure but have not been shown to reduce rates of illness or death. ACE inhibitors in combination regimens benefit younger patients with congestive heart failure, but concomitant left ventricular impairment increases the risk of hypotension from ACE inhibitors.
Recommendation 32: (a) An ACE inhibitor should be considered when diuretics or ß-blockers are contraindicated or not tolerated (grade B). Mild renal impairment does not contraindicate the use of ACE inhibitors in mild hypertension; (b) ACE inhibitors should be given in low initial doses and with caution in elderly patients (grade D). To minimize the risk of hypotension, diuretics should be withheld for 1 to 3 days before therapy with an ACE inhibitor is started.
Recommendation 33: Caution: Because of the risk of acute renal failure or hyperkalemia, in elderly patients with severe hypertension or congestive heart failure, especially those with abdominal bruits, diabetic nephropathy or decreased creatinine clearance, the serum creatinine and potassium levels should be measured before and after institution of therapy with ACE inhibitors (grade D). Acute mild increases in creatinine levels should not be considered a reason to discontinue ACE-inhibitor treatment.
Recommendation 34: Centrally acting agents and peripheral a-blockers are effective for decreasing blood pressure (grade B[31]). However, cognitive impairment resulting from therapy with methyldopa, postural hypotension from peripheral a-blockers (e.g., prazosin and terazosin[32]), drowsiness and rebound hypertension from clonidine and depression from reserpine may limit the use of these otherwise effective antihypertensive drugs in older people.[31]