3
High Blood Pressure

Reports on the prevalence of high blood pressure in the elderly indicate that between 30 and 50 percent of persons over the age of 50 may have chronic hypertension.7,25 Elevated levels of both diastolic blood pressure (DBP) and systolic blood pressure (SBP) are strong predictors of subsequent cardiovascular disease in the elderly.38 In the past two years there has been an explosion of new knowledge on the epidemiology, pathophysiology, and treatment of high blood pressure in older individuals.7

Because the risk of future cardiovascular morbid and mortal events rises in a continuous fashion as either systolic blood pressure or diastolic blood pressure rises, there is no threshold of either systolic or diastolic pressure that can be described definitively as hypertensive.40 Nonetheless, for operational purposes, this chapter will use the following definitions based on clinical conventions and on recommendations issued in 1985 by a National Heart, Lung and Blood Institute advisory committee (the Subcommittee on Hypertension Definition and Prevalence). Isolated systolic hypertension is defined as a systolic blood pressure greater than or equal to 160 millimeters of mercury (mmHg) and a diastolic pressure of less than 90 mmHg. Systolic/diastolic hypertension is defined as a diastolic blood pressure greater than or equal to 90 mmHg. This chapter focuses on the risk associated with high blood pressure, the efficacy and cost-effectiveness of detection and treatment (for the prevention of future complications), and recommendations regarding high blood



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The Second Fifty Years: Promoting Health and Preventing Disability 3 High Blood Pressure Reports on the prevalence of high blood pressure in the elderly indicate that between 30 and 50 percent of persons over the age of 50 may have chronic hypertension.7,25 Elevated levels of both diastolic blood pressure (DBP) and systolic blood pressure (SBP) are strong predictors of subsequent cardiovascular disease in the elderly.38 In the past two years there has been an explosion of new knowledge on the epidemiology, pathophysiology, and treatment of high blood pressure in older individuals.7 Because the risk of future cardiovascular morbid and mortal events rises in a continuous fashion as either systolic blood pressure or diastolic blood pressure rises, there is no threshold of either systolic or diastolic pressure that can be described definitively as hypertensive.40 Nonetheless, for operational purposes, this chapter will use the following definitions based on clinical conventions and on recommendations issued in 1985 by a National Heart, Lung and Blood Institute advisory committee (the Subcommittee on Hypertension Definition and Prevalence). Isolated systolic hypertension is defined as a systolic blood pressure greater than or equal to 160 millimeters of mercury (mmHg) and a diastolic pressure of less than 90 mmHg. Systolic/diastolic hypertension is defined as a diastolic blood pressure greater than or equal to 90 mmHg. This chapter focuses on the risk associated with high blood pressure, the efficacy and cost-effectiveness of detection and treatment (for the prevention of future complications), and recommendations regarding high blood

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The Second Fifty Years: Promoting Health and Preventing Disability pressure and its management directed toward elderly persons, health care professionals, and policymakers. The chapter does not discuss details of clinical diagnosis or treatment because these issues have been recently reviewed elsewhere.7 BURDEN Several epidemiologic studies have indicated that, in most countries, average systolic blood pressure increases throughout the life span whereas average diastolic blood pressure rises until ages 55 to 60 and then levels off.38 This increase in blood pressure occurs in persons who have previously been classified as hypertensive and those classified as normotensive. However, data from the Framingham longitudinal research and other studies indicate that not all individuals experience an aging-related increase in blood pressure.38 In addition, population studies from nonindustrialized societies indicate that average blood pressure among such groups does not tend to rise with age.51 Estimates of the true prevalence of high blood pressure vary greatly depending on the age and race of the population, the blood pressure level used to define hypertension, and the number of measurements made.15 The prevalence of both systolic/diastolic high blood pressure and isolated systolic high blood pressure is considerable in persons over the age of 50. Because levels of diastolic blood pressure tend to level off around age 55, the prevalence of systolic/diastolic high blood pressure tends to be constant for persons aged 50 and older.25 Therefore, although some authors speak in general terms of the rise in prevalence of high blood pressure with age, the prevalence of systolic/diastolic high blood pressure rises little with age.50 Actually, it is the rise in isolated systolic high blood pressure that accounts for most of the overall increase; the prevalence of systolic/diastolic high blood pressure in persons over the age of 50 is about 15 percent in whites and 25 percent in blacks.33 The prevalence of isolated systolic high blood pressure varies with increasing age from 1 or 2 percent at age 50 to greater than 20 percent over age 8032,50,57 and does not appear to differ according to race. Therefore, the total prevalence of high blood pressure in the elderly is not quite as high as the 50 to 60 percent figure that is frequently reported.63 Unfortunately, there are only limited data to estimate the rate of onset of new incidence cases of high blood pressure in the elderly. Follow-up analyses of the National Health and Nutrition Examination Survey 1 (NHANES1) data indicate that the incidence of high blood pressure (defined as SBP > 95 mmHg, based

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The Second Fifty Years: Promoting Health and Preventing Disability on one blood pressure measurement) increases by about 5 percent for each 10-year interval after age 18 and peaks between 55 to 64 years of age. The reported incidence rates from the NHANES data over an average of 9.5 years of follow-up were approximately 20 percent for white men and women over the age of 55 and 30 and 40 percent for black males and females, respectively. Based on the definition used, these rates would include both systolic/diastolic high blood pressure and isolated systolic high blood pressure. The estimates are inflated, however, because they are based on only one blood pressure reading per study (the original survey and the follow-up) taken more than 9 years apart. Analysis of Framingham data (also based on one reading but measured biennially) indicates that the cumulative incidence of isolated systolic blood pressure is about 418 per 1,000 in men and 533 per 1,000 in women.77 Because of differences in definition and in the frequency of and intervals between measurements, these data are difficult to interpret. Nonetheless, it appears that the number of new incidence cases of isolated systolic high blood pressure continues to increase in persons over age 55. Although the clinical treatment of high blood pressure has classically focused on diastolic blood pressure levels, epidemiologic data indicate that, for middle-aged and older adults, the systolic blood pressure level is more predictive of future cardiovascular morbidity and mortality.13,37 Both systolic pressure and diastolic pressure, however, remain independently predictive of future vascular events. Analyses of Framingham data indicate that 42 percent of strokes in elderly men and 70 percent of strokes in elderly women are directly attributable to hypertension.37 Again, systolic blood pressure appears to be slightly more predictive of strokes than diastolic blood pressure, and the risk gradients for systolic blood pressure do not wane with advancing age. When all cardiovascular risk factors in the elderly are taken into account, it is clear that increased systolic blood pressure levels are the single greatest risk (other than age itself) for increased cardiovascular disease in persons over the age of 50.38 It is also clear that increased blood pressure interacts with other cardiovascular risk factors to compound the risks. For instance, although total serum cholesterol lessens somewhat as a cardiovascular risk factor in the elderly, it still confers some element of risk (especially when fractionated into the low-density lipoprotein/high-density lipoprotein [LDL/HDL] ratio) and compounds the risk for hypertensives.38 In addition, recent reports from the Framingham study indicate that left ventricular hypertrophy is more prevalent in older persons and highly correlated with increased systolic blood pressure.59 It has been known for some

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The Second Fifty Years: Promoting Health and Preventing Disability years that the development of left ventricular hypertrophy is itself an independent cardiovascular risk factor.36 It is also becoming clear that left ventricular hypertrophy in hypertensives confers increased risk of ventricular arrhythmias.43 Finally, data from the National Center for Health Statistics indicate that coronary heart disease is the most common cause and cerebrovascular disease the third most common cause of mortality and morbidity in persons over the age of 50. Even as age advances into the seventies and eighties, coronary heart disease and cerebrovascular disease continue to be among the three most common causes of both mortality and morbidity. Further data from the National Center for Health Statistics indicate that coronary heart disease and cerebrovascular disease account for a majority of the disability seen in the population between the ages of 50 and 75. After the age of 75, degenerative processes such as arthritis and dementia began to account for approximately an equivalent amount of disability. In terms of disease-related disability and health care expenditures for persons over the age of 50, cardiac and circulatory disorders are responsible for more than 50 percent of such expenses. PATHOPHYSIOLOGY The pathophysiology of both systolic/diastolic high blood pressure and isolated systolic high blood pressure in the elderly involves an increase in peripheral vascular resistance.7,45 Certainly, as humans age, structural changes in the blood vessels account for some of the change in peripheral resistance.30 It is also possible that functional changes in the vascular smooth muscle are a contributory factor.1,7 Actually, the overall pathophysiology of high blood pressure in black and elderly persons exhibits a similar profile.7,44,73 Both black and elderly hypertensives tend to be sodium sensitive and have low renin levels, as well as increased vascular resistance. It has been suggested that black hypertensives are particularly likely to conserve sodium with expansion in extracellular volume and consequent development of high blood pressure.44,73 UTILITY OF SCREENING Several studies have shown that the casual office blood pressure measurement is strongly predictive of subsequent cardiovascular and cerebrovascular events.37 Yet recent analyses of data collected in a national multicenter clinical trial (the Hypertension Detection and Follow-up Program) indicate that the average of multiple measures

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The Second Fifty Years: Promoting Health and Preventing Disability of blood pressure over several different visits is more likely to approximate a person's true individual blood pressure.55 In addition, studies have indicated that, at times, the office measurement of blood pressure consistently overestimates blood pressure in certain persons known to have "white coat hypertension."53 According to some recent research, values for ambulatory blood pressure measurement in middle-aged persons may be more predictive of end organ damage than are casual measures of office blood pressure.75 Questions remain, however, as to how prevalent pseudohypertension is in elderly persons, and this topic is an important area for continued investigation. Currently, it would appear that multiple office blood pressure measurements or, in selected situations, ambulatory blood pressure measurements are highly predictive of subsequent cardiovascular risk. Therefore, office or ambulatory blood pressure monitoring is sufficiently sensitive and specific as a screening test for true high blood pressure. Furthermore, although some investigators have recently determined that indirect assessment of blood pressure with a mercury sphygmomanometer may cause spuriously high readings of blood pressure in older persons with calcified arteries (as compared with direct intra-arterial measurement),60,71 experience with mass screening programs indicates that mercury sphygmomanometer blood pressure measurement is an acceptable screening test for a large majority of the population.56 EVIDENCE THAT TREATMENT IS BENEFICIAL The discussion in this section emphasizes data obtained from large, properly conducted randomized controlled trials. In instances in which such data are not available, data from cohort or case-control studies are reported. For the purposes of this analysis, studies of the efficacy of treating diastolic high blood pressure in the elderly are limited to randomized trials whose design and sample size are adequate to generate sufficient statistical power—specifically, to have greater than a 50/50 chance of detecting a 25 percent reduction in mortality or morbidity endpoints. In reviewing the studies discussed below, the reader should be aware that there is great variability among clinical trials in the way endpoints are classified. Because of the different ways events are categorized and because of limited sample sizes that do not allow for subgroup comparisons, it is often difficult to distinguish the impact of treatment on rates of specific endpoints such as stroke, congestive heart failure, or myocardial infarction.

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The Second Fifty Years: Promoting Health and Preventing Disability Evidence That Treatment of Systolic/Diastolic High Blood Pressure Is Beneficial There is ample evidence from large multicenter controlled trials that the treatment of systolic/diastolic high blood pressure in individuals between the ages of 50 and 69 years of age is beneficial.33,49,72 The results of these trials are summarized in Table 3-1. For persons over the age of 50, the Veterans Administration (VA) study reported a reduction (nonsignificant) in aggregate cardiovascular morbidity, the Hypertensive Detection and Follow-up Program (HDFP) reported a reduction in total mortality, and the Australian Trial on Mild Hypertension reported a trend toward reduced stroke and aggregate is chemic heart disease. The only subgroup data available on the effects of treatment analyzed by race and sex come from the HDFP and do not indicate that race and sex significantly affect the benefits of treatment. Because most major high blood pressure trials had studied only selected groups of ''young old" persons, the European Working Party on Hypertension in the Elderly was designed to study whether medication treatment of diastolic high blood pressure in older subjects reduced morbidity or mortality. This trial enrolled persons over the age of 60 (mean age, 72 years) into treatment or placebo groups.3 After an eight-year follow-up, analysis revealed no effects of medication on mortality from all causes but did show a significant (27 percent) reduction in the cardiovascular mortality rate. There was also a statistically significant (38 percent) reduction in cardiac mortality and a nonsignificant (P = .12) but impressive 32 percent reduction in cerebrovascular mortality. Treatment appeared to be effective for persons with entry systolic blood pressure from 160 to 239 mmHg, but the treatment did not appear to have an impact on participants with entry diastolic blood pressure in the range 90 to 95 mmHg.4 The reduction in endpoints seen in the intervention group disappeared in persons over the age of 80, suggesting that treatment might not be effective in persons of advanced age. However, the number of participants aged 80 and older was small, and these subgroup data thus are not definitive. Persons over the age of 80 with diastolic high blood pressure who are relatively biologically "young" could be treated; the rationale for treating biologically frail persons aged 80 or older (particularly those with substantial noncardiovascular comorbid problems) may be less compelling. In general, as shown in Table 3-2, treated patients over 60 years of age have relative reductions in cardiovascular morbidity or mortality similar to the reductions that occur in patients under 50 years of

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The Second Fifty Years: Promoting Health and Preventing Disability TABLE 3-1 Randomized Trials of the Treatment of Diastolic High Blood Pressure in the Elderly: Summary of Design and Outcome Studya Type Age (yrs.) Blood Pressure (mmHg)b Medicationc Outcome VA Randomized, double-blind, placebo-controlled 60–69 DBP 90–114 HCTZ/Reserpine A 32% decrease in cardiovascular morbidity, did not reach significance. Magnitude of difference consistent with overall study. HDFP Randomized, special care vs. referred care 60–69 DBP 90–115 CTLD/Reserpine or alphamethyldopa Statistically significant 16.4% reduction in total mortality for special care group. Austr. Randomized, double-blind, placebo-controlled 60–69 DBP 95–109 CTZ/various second step A 39% reduction in trial endpoints for this treatment subgroup; did not reach statistical significance but reduction similar to overall study group. EWPHE Randomized, double-blind, placebo-controlled 60–97 DBP 90–119 SBP 160–239 HCTZ-triamterene/alpha-methyldopa Significant 38% reduction in cardiac mortality; 32% reduction in cerebrovascular mortality did not quite reach significance. Coope Randomized, single-blind, no placebo for controls 60–79 DBP ≥ 05 SBP ≥ 1 70 Beta blocker/BNFZD A 30% reduction in fatal strokes; no effect on myocardial infarction. a VA = Veterans Administration Cooperative Study (see reference no. 73); HDFP = Hypertension Detection and Follow-up Program (see reference nos. 32 and 33); Austr = Australian Trial on Mild Hypertension (see reference no. 50); EWPHE = European Working Party on Hypertension in the Elderly (see reference nos. 2 and 3); Coope = Coope and Warrender study (see reference no. 16). b DBP = diastolic blood pressure; SBP = systolic blood pressure. c HCTZ = hydrochlorothiazide; CTZ = chlorothiazide; BNFZD = benfluorothiazide; CTLD = chlorthalidone.

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The Second Fifty Years: Promoting Health and Preventing Disability TABLE 3-2 Impact of Antihypertensive Therapy on Cardiovascular Morbidity and Mortality by Age Group   Relative Reductiona (percentage) Absolute Reductionb (per 1,000 person-years) Study < 50 Years >60 Years < 50 Years >60 Years Veterans Administration Cooperative (morbidity) 55 59 21 100 Hypertension Detection and Follow-up Program (mortality) 6 16 2 25 Australian Trial on Mild Hypertension (cardiovascular trial endpoints) 20 26 5 10 a Relative reduction = the percentage of decline in the event rate in the intervention group compared with the placebo group. b Absolute reduction = the total number of events prevented in the treatment group versus the comparison group per 1,000 person-years of treatment. age.7 Yet when these data are analyzed by the absolute number of events prevented per 1,000 person-years of treatment, it is also clear that more total events are prevented in participants over age 60.7 Elderly persons have higher rates of cardiovascular events; if they experience the same percentage of benefit as younger persons from drug treatment for diastolic high blood pressure, then the reduction in total number of events is greater in the older persons. Therefore, the benefit attributable to the treatment of diastolic high blood pressure increases with age and with the severity of the diastolic high blood pressure. The absolute benefit from drug treatment of diastolic high blood pressure in persons over the age of 60 varies from 10 events prevented per 1,000 person-years for individuals with mild diastolic high blood pressure (90 to 104 mmHg) to 100 events per 1,000 person-years for individuals with moderate diastolic high blood pressure (105 to 115 mmHg). Evidence That Treatment of Isolated Systolic High Blood Pressure Is Beneficial To date there are no data from randomized controlled trials to demonstrate that treatment of isolated systolic high blood pressure

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The Second Fifty Years: Promoting Health and Preventing Disability lowers subsequent rates of cardiovascular morbidity or mortality. In addition to the epidemiologic data reviewed above, however, there are data from one large cohort study indicating that, over a seven-year follow-up period, control of systolic pressure in treated hypertensives tended to result in more beneficial cardiovascular morbidity and mortality.6 Moreover, data from the Systolic Hypertension in the Elderly Program pilot study suggest that isolated systolic hypertension can be treated easily with minimum side effects.31 Impact of Treatment on Cerebrovascular Versus Coronary Heart Disease Clinical trials of the treatment of diastolic high blood pressure have shown that treatment reduces the rate of strokes and heart failure but has little effect on coronary heart disease rates.23 Possible explanations for this lack of benefit include the following: (1) the study cited may have had too short a duration to demonstrate a benefit in terms of the natural history of coronary heart disease; (2) some of the subjects in the studies may have experienced too vigorous a lowering of diastolic blood pressure, which may have adversely affected coronary artery blood flow, particularly to the subendocardial layer during diastole;20 or (3) it is possible that diuretics (which increase lipids and glucose and lower potassium) may have had adverse effects.40 Currently, the dilemma remains regarding the effect on coronary heart disease of treatment of high blood pressure. Target goals for blood pressure lowering should be modest. Three recent descriptive studies have shown that there may be a J-shaped relationship between treated levels of diastolic blood pressure and mortality from myocardial infarction; that is, those patients with the greatest lowering of diastolic pressure actually had higher rates of fatal myocardial infarction than did patients with more modest lowering. Two recent studies in middle-aged hypertensives,20,67 and one in elderly hypertensives6 have also shown this effect. Therefore, a modest lowering of DBP to about 85 to 88 mmHg appears most appropriate for the elderly. Impact of the Treatment of High Blood Pressure on Total Mortality With the exception of the Hypertension Detection and Follow-up Program, none of the large multicenter trials shown in Table 3-2 have demonstrated that treatment of high blood pressure has an impact on total mortality. Some have viewed this finding as a

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The Second Fifty Years: Promoting Health and Preventing Disability rationale for not recommending treatment for high blood pressure; it should be noted, however, that the size of the samples used in these clinical trials were inadequate to test a hypothesis with regard to effects of treatment on total mortality. When the results of all randomized trials of the treatment of diastolic high blood pressure were recently pooled in a meta-analysis, it appeared that a small but significant reduction in total mortality may have occurred across all age groups.42 The data are inadequate, however, to draw conclusions about the impact of the treatment of high blood pressure on total mortality in persons over the age of 50. Adverse Effects of Antihypertensive Therapy Concerns about toxicity resulting from antihypertensive therapy in the elderly have led many authors to advise restraint or even therapeutic nihilism with respect to the treatment of high blood pressure in this group.76 Theoretically, there are several reasons why the risk/benefit ratio for the treatment of high blood pressure might increase with age. It is believed that the elderly are particularly susceptible to many of the side effects of antihypertensive medication.34,76 For instance, elderly patients are more likely to develop hyponatremia and hypokalemia when treated with standard doses of diuretics.27,34 It is also thought that older patients are more likely to develop side effects such as depression and confusion when treated with antihypertensive medications that affect the central nervous system (e.g., beta-blockers or drugs that affect the alpha adrenergic nervous system).9 There is good evidence to indicate that the baroreceptor reflex becomes less sensitive with age.28,41 As a result, the elderly could be more sensitive to the postural hypotensive effects of antihypertensive medications, with a consequent increased propensity for falls and fractures.14 Although some have argued that elderly persons with high blood pressure actually need higher blood pressure for adequate perfusion of vital organs (e.g., the brain and kidney),35 most studies have not shown that judicious use of antihypertensive medications in the elderly has a significant adverse effect on either renal or cerebral perfusion.12,55,68 It is clear from the work of Strandgaard that in middle-aged patients with chronic essential hypertension the pressure-flow curve for cerebral auto-regulation is reset to the right. The chronic hypertensive thus would be more susceptible to cerebral hypoperfusion if mean arterial pressure were lowered substantially and acutely.66 It is quite possible that a similar situation might exist in an elderly patient who had high blood pressure for a number of

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The Second Fifty Years: Promoting Health and Preventing Disability years. Further work indicates that cautious, slow lowering of blood pressure to normal levels in the chronic hypertensive together with continued control results in a resetting of the cerebral pressure-flow auto regulation curve to the left—the more normal configuration.10,63 A few studies in middle-aged hypertensives suggest that acute initiation of antihypertensive drugs can lower cerebral perfusion modestly,12 but chronic administration of appropriate doses of antihypertensive medications does not adversely affect cerebral blood flow.12,66,67 It is surprising that there are few data from large-scale clinical trials regarding the toxicity of antihypertensive medication in the elderly. A group of investigators from the Hypertension Detection and Follow-up Program reported that the total rate of adverse effects from the treatment of mild to moderate systolic/diastolic high blood pressure was less for the subgroup aged 60 to 69 at entry than for those under the age of 50.22 These data are helpful but should be viewed with caution: persons in the 60-69 age range are classified as the "young old" and may not be as susceptible to side effects as the "old old" (aged 75 and older). In addition, such trials tend to select "well" subjects and are not necessarily representative of elderly patients who have one or more serious comorbid diseases. The largest available data set on the toxicity of antihypertensive therapy in the elderly comes from the European Working Party on Hypertension in the Elderly and its randomized study of the efficacy of the treatment of systolic/diastolic high blood pressure in a cohort of patients with a mean age at entry of 72 years.4 Early reports from this trial indicate that treatment with a thiazide-triamterene combination (followed by alphamethyldopa as a second-step agent when needed) resulted in mild increases in glucose intolerance, serum creatinine, and uric acid and a mild decrease in serum potassium in the treatment group.2 Treatment does not appear to have had a significant long-term effect on serum cholesterol levels.5 To date, only limited data on side effects have been reported, but there was no significant difference between the treatment and control groups in the rate at which patients were dropped from the study because of presumed drug-related side effects. The biochemical side effects listed above were not thought to outweigh the benefits of treatment. Questions still remain about possible negative impacts of antihypertensive therapy on the quality of life for elderly patients. Only a few trials of antihypertensive drug therapy (in any population, young or old) have adequately quantified the impact of reported adverse effects on subjects' quality of life.19,70 Most trials have simply counted the total number of reported adverse effects without attempting to describe either qualitatively or quantitatively their

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The Second Fifty Years: Promoting Health and Preventing Disability impact on physical, emotional, or cognitive function or overall perceptions of quality of life.67 Quality of life issues that are important to the elderly and that may be influenced by antihypertensive therapy (but that have not been well studied) include emotional state (depression, life satisfaction, anxiety), cognitive or intellectual processing (memory, psychomotor speed, problem solving), physical functioning (ability to perform self-care tasks, upper and lower extremity speed, gait and balance), and social interaction (social activities, contacts).75 The adage, "in the elderly it is as important to add life to years as years to life," is relevant here. NONPHARMACOLOGIC THERAPY Nonpharmacologic therapy, including weight loss, sodium restriction, moderate consistent aerobic exercise, and relaxation therapy all may be helpful in individual patients, particularly those with borderline elevations of blood pressure.40 Unfortunately, the only available studies of the efficacy of these measures have been conducted in young to middle-aged patients.61 Currently, data indicate that, if the patient is overweight, moderate weight loss is the most effective nonpharmacologic treatment for high blood pressure, although questions remain regarding the efficacy of weight loss because many patients regain the lost weight over an extended period of time.11 Studies of sodium restriction indicate that approximately one-third of hypertensive patients respond to sodium restriction, especially if sodium intake can be decreased below 80 milliequivalents per day.69 There is some evidence that elderly hypertensives are more sodium sensitive than younger hypertensives, particularly among blacks.68,78 Because the diet of many elderly persons includes substantial quantities of prepackaged or canned foods that are high in sodium, clinicians frequently find that their elderly patients would rather take a diuretic than severely restrict their salt intake. The limited data currently available on the impact of exercise and relaxation therapy on high blood pressure indicate that both interventions can have modest, short-term beneficial effects on blood pressure. SUMMARY OF INTERVENTION DATA In summary, it appears that treatment of diastolic high blood pressure in elderly persons is warranted but that the magnitude of benefit may be marginal in persons of advanced age or persons with very mild high blood pressure. In those cases, it is important to consider other parameters such as quality of life or economic status.

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The Second Fifty Years: Promoting Health and Preventing Disability The goal for treatment should be a modest lowering of blood pressure, as noted above. Currently, there are insufficient data to draw conclusions regarding the treatment of isolated systolic high blood pressure. COST-EFFECTIVENESS OF TREATMENT FOR HIGH BLOOD PRESSURE IN PERSONS OVER 50 There have been few adequate cost-effectiveness analyses of the treatment of high blood pressure in persons over the age of 50. An early cost-benefit analysis conducted by Stason and Weinstein63 showed that the cost-benefit ratio for the treatment of diastolic high blood pressure appeared to improve as the severity of diastolic high blood pressure increased. Their analyses indicated that the cost of treatment to provide an additional year of quality-adjusted life could vary from $5,000 to more than $20,000 per year, depending on the age of the patient and compliance with treatment. In addition, their analyses indicated that the impact of treatment on quality-adjusted life years might be negligible after age 60. However, analyses of results of the European Working Party on Hypertension in the elderly4 plus new information from recent trials indicate that the treatment of moderate and severe diastolic high blood pressure (DBP > 100 mmHg) in persons over the age of 50 is probably cost-effective when compared with other standard preventive therapies. No definitive statement is possible regarding the cost-effectiveness of treating mild diastolic high blood pressure (DBP of 90 to 99 mmHg) in the elderly). In discussing cost-effectiveness, it should be pointed out that the individual benefit may be small, but the population benefit may be great. In an analysis of its treatment trial for mild hypertension, the British Medical Research Council determined that in order to prevent one stroke, 850 persons had to be treated for one year. Further analysis showed that, in the population treated, there was a 45 percent reduction in stroke incidence.80 SUMMARY In conclusion, systolic/diastolic high blood pressure and isolated systolic high blood pressure are sufficiently prevalent to be considered important risk factors in persons over the age of 50. In addition, epidemiologic studies indicate that both systolic blood pressure elevations and diastolic blood pressure elevations are significant independent risk factors for subsequent cardiovascular and cerebrovascular morbidity and mortality; however, elevation of systolic

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The Second Fifty Years: Promoting Health and Preventing Disability blood pressure is the single most powerful cardiovascular risk factor in persons over the age of 50. Because cerebrovascular and cardiovascular morbidity and mortality impose a substantial burden on the elderly, treatment of high blood pressure should be considered. Current data from randomized controlled clinical trials indicate that the treatment of moderate to severe diastolic high blood pressure in the elderly is, indeed, warranted; treatment of mild diastolic high blood pressure in the elderly should be left to the judgment of individual clinicians and patients. The data are too limited at present to make a definitive statement about the treatment of isolated systolic hypertension. RECOMMENDATIONS Services Persons aged 50 and older without known cardiovascular disease should have their blood pressure checked: once every two years if their pressure has been normal previously and they have no family history or risk factors for cardiovascular disease (see also the clinical recommendations below); at least once per year if they have a family history or other risk factors for cardiovascular disease; or at least every six months if they have a past diagnosis of high blood pressure. Persons aged 50 and older with known cardiovascular disease should have their blood pressure checked at every physician visit and at least once per year if pressure previously was normal or every six months if the individual was previously thought to be hypertensive. Clinical Note: Patient blood pressures for assessment of hypertension should be based on the average of three measures taken during three visits. Patients with diastolic blood pressure greater than 100 mmHg should be treated pharmacologically. For patients with diastolic blood pressure of 90 to 100 mmHg,

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The Second Fifty Years: Promoting Health and Preventing Disability nonpharmacologic therapy is recommended. If after three to six months, diastolic pressure is greater than 95 mmHg, a pharmacologic therapy regimen should be initiated.* For patients with systolic blood pressure greater than 160 mmHg and diastolic pressure less than 90 mmHg, physician discretion should be used regarding therapy. However, in no case should therapy be aggressively pursued in the face of continued disabling side effects. Patients should be informed of the actual expected magnitude of reduction in morbidity and mortality for pharmacologic treatment of their level of blood pressure as some may rationally prefer no treatment. Research The elderly should be included in studies of the efficacy and adverse effects of newer antihypertensive agents, treatments for mild diastolic high blood pressure, and nonpharmacologic interventions. Methods for better risk stratification of elderly hypertensives should be developed to improve the accuracy of predictions of risk and contribute to more informed treatment of mild hypertensives in high-risk strata. Studies should be conducted to examine the impact of the treatment of high blood pressure on cognitive function, mood, physical function, and quality of life. The prevalence of false-positive diagnoses of high blood pressure in the elderly should be studied. Policy Medicare and private insurance should offer reimbursement for blood pressure screening. Strategies should be devised to promote the detection and treatment of high blood pressure in those sectors of the over-50 population that are likely to have access only to periodic medical care—especially black males and isolated elderly persons. *   When pharmacological therapy is chosen, the clinician should begin with one-half the usual dose and proceed slowly. Whenever possible, adjuvant nonpharmacologic therapy should be used.

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