Nondrug approaches to hypertension  added 11/09/01

Patient Care  Jun. 15, 2001 http://pc.pdr.net/pc/public.htm?path=content/journals/p/data/2001/0615/06a01nondrug.html

Nonpharmacologic approaches to hypertension (HT) have typically yielded modest reductions in BP, largely because of difficulties with patient adherence. Yet a consensus has emerged that these therapies should be an integral part of the prevention and treatment of HT, which is the most common diagnosis among patients making primary care office visits in this country.¹ The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) places a greater emphasis on nondrug approaches than in earlier reports, recommending lifestyle modifications for all patients with HT.^2,3 Recent advances in research have led to updates of tools and guidelines for using nondrug therapies that significantly enhance the facility, efficiency, and scope of these approaches.

Moreover, the need for improved treatment for the 50 million people with HT in the United States remains clear. Although substantial progress has been made in lowering BP with drugs, the most recent nationwide data still indicate that only about 25% to 30% of people with diagnosed and treated HT have their BP controlled to 140/90 mm Hg or lower.^4,5 Current research suggests that lifestyle modifications could play an essential role in controlling high BP, if pursued with conviction and patience.

Nonpharmacologic therapies are recommended for preventing HT in people with normal or high-normal BP, for the treatment of stage 1 HT, or as an adjunct to pharmacotherapy.² The JNC VI report recommends a risk stratification approach for application of nondrug therapies, using BP level stages and disease factors as criteria (see Tables 1 and 2). Achievable goals with these approaches include enabling some patients to avoid lifelong drug therapy, enhancing the effectiveness of antihypertensive drugs, and allowing step-down or elimination of medications. Furthermore, the side effects of nondrug therapies are generally beneficial, including lowered risks for stroke, cardiovascular and kidney disease, prevention of some cancers, and better overall health.

GUIDELINE

BP stage
(mm Hg) Risk group A:
no risk factors, TOD/CCD Risk group B:
>1 risk factor not including diabetes; no TOD/CCD Risk group C:
TOD/CCD and/or diabetes,
with or without other
risk factors

High-normal
130-139/85-89 Lifestyle modification Lifestyle modification Drug therapy and lifestyle modifications*

Stage 1
140-159/90-99 Lifestyle modification up to 12 mo Lifestyle modifications up to 6 mo† Drug therapy and lifestyle modifications

Stages 2 and 3
>160/>100 Drug therapy and lifestyle modifications Drug therapy and lifestyle modifications Drug therapy and lifestyle modifications

Key: CCD, clinical cardiovascular disease; TOD, target-organ disease.
*For those with heart failure, renal insufficiency, or diabetes.
†For patients with multiple risk factors, physicians should consider drugs as initial therapy plus lifestyle modifications.

Source: Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNCVI). Bethesda, Md:National Institutes of Health, National Heart, Lung, and Blood Institute; 1997. NIH publication 98-4080. Available at: http://www.nhlbi.nih.gov/guidelines/hypertension/jncintro.htm . Accessed March 1, 2001.

GUIDELINE

Major risk factors
Age >60 y
Diabetes mellitus
Dyslipidemia
Family history of CVD (women <65 y or men <55 y)
Sex (men and postmenopausal women)
Smoking

Target-organ damage/clinical CVD
Heart diseases
   Angina/prior MI
   Heart failure
   Left ventricular hypertrophy
   Prior coronary revascularization
Nephropathy
Peripheral arterial disease
Retinopathy
Stroke or transient ischemic attack

Key: CVD, cardiovascular disease.
Source: Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNCVI). Bethesda, Md:National Institutes of Health, National Heart, Lung, and Blood Institute; 1997. NIH publication 98-4080. Available at: http://www.nhlbi.nih.gov/guidelines/hypertension/jncintro.htm . Accessed
April 23, 2001.

Under ideal conditions, lifestyle modifications can reduce BP to a degree comparable to the effect of one antihypertensive drug. The most well-supported and broadly applicable nondrug strategies for reducing BP are

• Weight loss in patients who are overweight

• A healthy diet (rich in fresh fruits, vegetables, and low-fat dairy products; low in processed foods)

• Reduced sodium intake

• Regular physical activity

• Increased dietary potassium.

For patients who drink alcohol excessively, reduction of drinking to the moderate levels of two drinks a day for men and one for women, or elimination of alcohol, may be helpful since alcohol has well-characterized aggravating effects on HT. Smoking cessation is also important to help reduce HT as well as the risk of heart disease. (Cigarettes elevate BP transiently during the act of smoking.)

Therapies with less evidence in their favor include

• Stress reduction, including behavior modification, meditation, deep breathing, and biofeedback

• Increased calcium intake

• Increased dietary magnesium.

Each of the nondrug approaches for which supporting data are strong can independently lower BP. As in drug therapy, consistent BP reduction depends on the consistency of adherence. Implementation of all applicable modalities for a given patient will yield the best results but may have less than a fully additive effect. Research indicates that some modalities are generally more effective than others.

Obesity is a major cause of HT, and the most consistent and significant reductions in BP by nondrug therapies have been seen with weight loss. Possible mechanisms by which obesity may affect BP include disordered metabolism of fatty acids, causing insulin resistance; activation of the sympathetic nervous and plasma renin/aldosterone systems; and abnormal renal sodium handling.

An appreciable reduction in BP can be seen with weight loss of as little as 10 lb in overweight people with HT.² A recent database review found that a weight reduction of 4% to 8% corresponded to a BP decrease of 3 mm Hg systolic and diastolic.⁶ In a 1997 study of 2382 moderately overweight men and women with high-normal diastolic BP, weight loss of about 10 lb was found independently to decrease BP by 3.7/2.7 mm Hg.⁷ Illustrating the difficulties that sometimes attend this approach, however, the subjects in this study progressively regained almost all their lost weight over a 36-month period, at which point the net reduction in BP was only 1.3/0.9 mm Hg. Nonetheless, the 13% of study participants who maintained their weight loss throughout the 36 months also sustained their BP reduction.⁸

The first Dietary Approaches to Stop Hypertension (DASH) trial tested the capacity of nutritional interventions other than salt reduction and weight loss to lower BP in 459 people with pressures of less than 160 mm Hg systolic and from 80 to 95 mm Hg diastolic.⁹ The study found that, in a 3-week period, a diet rich in fruits, vegetables, and low-fat dairy products and characterized by restricted saturated and total fat lowered BP 5.5/3.0 mm Hg more than a control diet. This occurred in subjects with stable weight and sodium intake of 3000 mg/d over the trial period.

DASH-Sodium, the second DASH trial, reported earlier this year, tested the combined effect of the DASH diet with high, intermediate, and low levels of sodium for 30 consecutive days in 412 subjects with BPs from 120/80 mm Hg to higher than 160/95 mm Hg.¹⁰ The study found that progressively lower sodium levels reduced BP; that the DASH diet reduced BP at every sodium level but most markedly at the higher sodium levels; and that the low sodium (1500 mg/d)/DASH combination lowered BP to the greatest extent of all diets tested, although the effect was not strictly additive. The combination diet reduced systolic BP by 11.5 mm Hg in hypertensive people and by 7.1 mm Hg in normotensive subjects.

The effect of the combination low-sodium/ DASH diet can approximate that of one antihypertensive drug.¹⁰ By increasing intake of fruits and vegetables while proportionally decreasing consumption of processed foods typically high in salt, this diet efficiently incorporates multiple dietary goals to lower BP and simplifies implementation of these strategies for patients.

The effect of dietary sodium on BP has been a matter of controversy for a full century.¹¹ Plausible mechanisms for how salt intake affects BP through the renin-angiotensin-aldosterone system have been established, and a number of major studies and reviews support the independent effect of decreased salt intake in significantly lowering BP. But other studies have found a smaller effect in lowering BP from sodium reduction and increased mortality in people with low sodium excretion, casting doubt on the value and safety of this strategy. The latest research has not fully resolved the controversies over BP and salt consumption (see "A review of selected recent studies on sodium and HT").

A meta-analysis of 56 randomized controlled trials.

Results Sodium reduction lowered BP by 3.7/0.9 mm Hg in the hypertensive trials and 1.0/0.1 mm Hg in normotensive subjects.

Conclusion Sodium restriction may be effective for older hypertensive people, but a universal recommendation for sodium reduction is not supported.¹

Further assessment of international populations first studied in 1988: 10,074 men and women aged 20 to 59 in 32 countries.

Results An increase in urinary sodium excretion of 100 mmol/d correlated with BP elevation of 5-7/2-4 mm Hg. If sustained for 30 years, a 100 mmol/d higher sodium excretion will result in BP elevation greater by 10-11/6 mm Hg.

Conclusion These results lend support to mass reduction of sodium intake for prevention and control of HT.²

Randomized, blinded, multicenter clinical trial: 2382 men and women aged 30 to 54 with a systolic BP of under 140 mm Hg and diastolic BP of 83 to 89 mm Hg.

Results Sodium reduction lowered BP by 2.9/1.6 mm Hg and 1.2/0.7 mm Hg at 6 and 36 months, respectively.

Conclusion Sodium reduction is effective in lowering BP, both independently and in combination with other therapies.³

Observational study using multiple regression analyses to assess the relation of sodium intake to subsequent all-cause mortality in a general population: 20,729 adults aged 25 to 75 traced through follow-up investigation.

Results Sodium intake was inversely associated with all-cause and cardiovascular disease (CVD) mortality. However, when sodium intake was adjusted for calorie intake, the opposite result was found.

Conclusion No recommendations to change dietary sodium intake in any way are justified based on the evidence of this study.⁴

Randomized controlled trial: 875 men and women aged 60 to 80 with BP lower than 145/85 mm Hg while receiving one antihypertensive drug.

Results Sodium reduction allowed antihypertensive drug therapy to be stopped in 92.6% of subjects; 38% remained off drug therapy while maintaining a BP of less than 150/90 mm Hg after 30 months, with no evidence of CVD.

Conclusion Reduced sodium is a feasible, safe, and effective therapy for HT in older people.⁵

Meta-analysis of randomized controlled trials: Computer literature search of relevant articles from 1966 through 1997; 114 study population trials were reviewed.

Results Sodium restriction lowered BP by 3.9/1.9 mm Hg in people with HT and by 1.2/0.26 mm Hg in people who did not have HT.

Conclusion A general recommendation to reduce sodium intake is not supported, but sodium restriction may be used as a supplementary treatment to HT.⁶

A 6- to- 8-year follow-up study of 181 men and women aged 30 to 54, with BP of less than 160/80-89 mm Hg, who participated in TOHP Phase I.

Results After 7 years of follow-up, the incidence of HT was 22.4% in the sodium reduction group and 32.9% in the control group, a decrease of 35% in statistical odds for HT in the sodium reduction compared with the control group.

Conclusion Sodium reduction should be recommended as a principal component of strategies to prevent HT in the US general population.⁷

A randomized outpatient feeding trial comparing the effects on BP of three levels of sodium intake in two diets: 412 men and women with BP levels of 120-159/80-95 mm Hg.

Results The lowest sodium level (1500 mg/d) coupled with the DASH diet yielded a 6.7-mm Hg reduction in systolic BP as compared to the high-sodium control diet, and achieved a 3.0-mm Hg reduction in systolic BP when combined with the DASH diet, relative to a high-sodium DASH diet.

Conclusion The reduction of sodium intake to levels below the current recommendation of 2400 mg/d independently lowers BP significantly, and the combination of the DASH diet with maximum sodium reduction is most effective.⁸

1. Midgley JP, Matthew AG, Greenwood CM, et al. Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials.. JAMA. 1996;275:1590-1597.

Guidelines Consensus does exist that people in this country consume too much dietary salt. Whereas average sodium intake is estimated at 3500 to 3900 mg/d, dietary guidelines of the US Department of Agriculture (USDA) and US Department of Health and Human Services (HHS) refer to the Daily Value of the FDA, which recommends consumption of no more than 2400 mg/d. The JNC VI report recommends that salt intake be limited to the FDA Daily Value level and that moderate sodium reduction be used, along with other lifestyle modifications or as an adjunct to drug therapy, for prevention and treatment of HT.²

Established data Although experts continue to disagree on whether decreased salt intake should be recommended for prevention of HT, few dispute that sodium reduction independently and significantly lowers BP in hypertensive people while posing minimal risk.¹² That most hypertensive African Americans and older people are salt sensitive and may particularly benefit from sodium restriction is also beyond contention. The established data strongly suggest that sodium reduction remains a valuable component of nondrug therapy.

Aerobic physical activity of moderate intensity, such as walking, jogging, cycling, or swimming, performed 3 to 5 times a week, can achieve significant BP reductions. Recent reviews estimate that physical activity can decrease BP in the range of 11/8 mm Hg in hypertensive people and 4/4 mm Hg in normotensive people.^13,14 Research has also shown consistently that mild to moderate activity may be even more effective in lowering BP than high-intensity exercise.^13,14 A recent 24-month study found that lifestyle physical activities that are amalgamated into daily routines are as effective as structured exercise regimens in promoting fitness and lowering BP.¹⁵

The physiological mechanism by which physical activity reduces BP is unknown. Although the weight loss often produced by exercise is a factor, evidence also suggests that physical activity independently lowers BP.¹³

Guidelines The JNC VI guidelines suggest 30 to 45 minutes of brisk walking on most days of the week, at an intensity of 40% to 60% of maximum oxygen consumption.² A walking rate of about 3 miles per hour (mph), or enough activity to feel slightly winded with light perspiration, is a reasonable recommendation. Some experts, however, believe exercise intensity in the range of 70% maximum oxygen consumption is necessary to achieve significant BP reductions. Benefits can be seen at 3 days per week and are increased with greater frequency. Little additional benefit accrues by increasing frequency from 5 to 7 days a week, however.

Exercise options In addition to aerobic activity, progressive resistance exercise may also yield modest BP reductions of about 3/2 mm Hg.¹⁶ Appropriate circuit weight training typically comprises 10 to 15 repetitions per set with weights of 30% to 50% of maximum load and rest intervals of 15 to 30 seconds. Anaerobic heavy lifting should be avoided by patients with any signs of cardiovascular disease (CVD) since systolic BP can spike to well over 200 mm Hg with such activity.

An inverse relationship between potassium intake and BP has long been noted but, until recently, reviews of the literature on this association have been inconclusive. A 1997 meta-analysis of 33 randomized controlled trials of potassium supplementation found that this intervention lowered BP in hypertensive people by 4.4/2.5 mm Hg and in normotensive people by 1.8/1.0 mm Hg.¹⁷ The JNC VI report recommends intake of 90 mmol/d (3500 mg/d) of potassium, preferably from foods rather than supplements (see Table 3). The JNC advises caution in the use of potassium supplements for patients susceptible to hyperkalemia, those with renal insufficiency, or patients receiving ACE inhibitors or angiotensin II receptor blockers.

Vegetables
Asparagus
Baked sweet or white potato
Cooked greens (such as spinach, swiss chard)
Corn
Green beans
Green peas
Tomatoes
Winter (orange) squash, pumpkin

Fruits
Bananas
Cantaloupe
Dried fruits such as apricots, prunes, and raisins
Grapefruit
Honeydew
Oranges

Legumes
Cooked dry beans (such as baked, black, chili, kidney, or lima)
Legumes (such as chick peas, green or yellow split peas, and lentils)

Source: The consultants for this article and Dietary Guidelines for Americans, US Dept of Agriculture, 5th ed. 2000. Available at: http://www.nal.usda.gov/fnic/dga/ . Accessed April 23, 2001.

Some studies have indicated that increased intake of calcium and magnesium can yield small BP reductions in people with HT. Although the data do not support recommendations for higher intake of these minerals to reduce BP, adequate amounts should be included as part of the dietary program.

Although stress can raise BP acutely, intervention trials using relaxation and behavioral modification techniques to lower BP have not shown significant effects. Yet all lifestyle modifications depend on patient adherence; and stress, by generating behaviors such as overeating, drinking, and smoking, is often disruptive to these efforts. Stress reduction, as tailored to individuals, may be necessary for success in using nondrug therapies.

Although lifestyle modifications are recommended for all patients along the guidelines suggested by JNC VI, selection of one or more therapies should be customized for best effect. Salient clinical factors, behaviors, demographic considerations, or patient preferences may present obvious choices. Patients who smoke, for example, must first be urged to stop smoking, and those who drink more than the recommended levels of alcohol should be told to cut down or eliminate drinking entirely. The extent of a patient's obesity may determine the intensity of focus on weight reduction. Whether therapies are implemented singly, in combination, or gradually phased in may be determined by the patient's ability and willingness to sustain lifestyle modifications.

Patients overcome with stress might best be advised to undergo behavioral modification along with other appropriate modalities. In addition, tendencies in patient subgroups may also be considered.

African Americans HT is much more prevalent and severe, begins earlier in life, and exacts a much higher toll in related disease and mortality in African Americans than in white Americans.^2,18 African Americans also demonstrate greater changes in BP in response to increases or decreases in dietary sodium than other ethnic groups.¹⁸ Lifestyle modifications have produced some striking effects in lowering BP in African Americans. In a trial of potassium supplementation, average BP reduction in 13 African American participants was 20/13 mm Hg as compared to 6.5/2.5 mm Hg for the total group of 101 subjects.¹⁷ The DASH-Sodium trial showed that a combination low-sodium/DASH diet lowered systolic pressure by 12.6 mm Hg in hypertensive African Americans and 9.5 mm Hg in all others with hypertension.¹⁰

Older people Lifestyle modifications are a way to counteract the common tendencies of aging, such as decreasing physical activity and weight gain, which help cause HT. In addition, salt sensitivity, and the BP elevation associated with it, increase with age, making dietary sodium reduction all the more important for these patients.¹⁹ The Trial of Nonpharmacologic Interventions in the Elderly (TONE) showed that the need for antihypertensive drugs in older people could be reduced by approximately 30% through sodium reduction and weight loss.²⁰

Normotensive people Which healthy patients with normal BP should be advised to adopt lifestyle modifications as preventive measures for HT? Family history of HT is an important factor. One way to select appropriate candidates is to check their trend of weight gain, rather than only their weight at the time of examination. If a patient aged 30 to 35 has gained 5 lb since age 20, he or she is likely to continue putting on pounds until overweight and at risk for HT. A discussion of exercise and diet may be appropriate before obesity and high BP develop. In people with high-normal BP, lifestyle modifications may be the last chance to prevent HT.

Patients with diabetes The recommended target BP for people with diabetes is now 130/85 mm Hg and lower, and lifestyle modifications in tandem with drug therapy are strongly advised to help reach this control threshold.² Weight loss and exercise, linchpins of all diabetes treatment, are particularly important to emphasize for BP reduction. In addition, insulin promotes renal tubular sodium resorption, and sodium reduction may thus be helpful in counteracting the development of HT caused by diabetes.²¹

After initiation of one or more nondrug therapies, monitor the patient regularly and then reevaluate. For a woman with no risk factors and stage 1 HT, a 1-year trial of nondrug approaches is reasonable; for a man in the same category, 6 months is recommended.

Patients taking antihypertensive drugs and trying lifestyle modifications should demonstrate good BP control for at least 6 to 9 months, or several readings, before you consider step-down of dosage or number of medications. Some experts recommend controlling BP with drugs and lifestyle modifications for 3 to 5 years before making any changes in pharmacotherapy. Once the drug regimen is adjusted, the patient should be seen in a week, and then at frequent intervals, for monitoring because BP may bounce up. Yet complete withdrawal of all medication is achievable without precipitating cardiovascular events. A recent study found that antihypertensive drugs can be safely discontinued in elderly patients with BP lower than 150/90 mm Hg, as long as they continue to control their BP with nondrug therapies.²²

You might also recommend that patients check their BP at home and keep a record of it. The goals for home readings should be 5 points lower than at the office, for example, 135/85 mm Hg as opposed to 140/90. The patient's home monitoring device should also be checked for accuracy against the one you are using at the start of therapy and annually after that. Aside from BP readings, 24-hour urine tests of sodium or potassium may be helpful to check progress on dietary therapies. In general, expectations must be tempered by the understanding that lifestyle modifications require a period of adjustment.

Dietary Once people reduce salt intake, their taste for the seasoning tends to decrease after 8 to 12 weeks and unsalted foods become more appealing.²³ Learning to read food labels for sodium content, cooking low-salt meals, and phasing more high-potassium foods into the diet can be a lengthy process. Sodium is found in high quantities in most processed foods, from cheese to bread.

One useful guideline for patients is to buy only canned or processed foods that contain 5% or less of the Daily Value of sodium intake (2400 mg/d); the percentage is usually listed on the label along with the sodium amount in milligrams. Because softened water is also a source of sodium, patients should make sure that the cold water line to the kitchen for drinking and cooking is not softened.

A general strategy is to switch, as much as possible, from pre-prepared, processed, and restaurant meals, all usually high in sodium, to home-cooked foods using unsalted fresh ingredients high in potassium, calcium, and magnesium. Use of the DASH diet, available on the DASH Web site at http://dash.bwh.harvard.edu/ research.html, may be extremely helpful. The guidelines and general information cover a multitude of questions, with daily and weekly guides that remove much of the guesswork for patients.

Weight loss A weight-loss program may take several months to show effects both in reduced body weight and lower BP. In patients with high-normal BP or stage 1 HT, waiting 6 months to 1 year for weight loss to take effect is reasonable as long as some progress is apparent. Intensifying the exercise component of the program as appropriate may yield further benefits.

Physical activity Patients should have their BP controlled to lower than 180/105 mm Hg by nonpharmacologic or antihypertensive drug therapy before they are prescribed a physical activity program. In addition, beta-blocker therapy may impair exercise capacity. Although effects of regular exercise can be detected after only 4 to 5 weeks, optimum BP decreases usually take a minimum of 10 weeks of sustained physical activity to achieve; the effects will be lost after 10 weeks of deconditioning.

If BP is not controlled to the target level at reevaluation, a number of options are possible, depending on BP levels and patient adherence. You might try phasing in additional therapies if the patient's clinical profile and willingness to try them indicate some chance of success. If the patient has been implementing the therapies diligently with no effect and further modifications do not appear promising, drug therapy—in addition to continued healthy living—is recommended.

Conveying your belief in the value of nondrug therapies strongly and consistently to patients is vital to the success of these approaches. Any available in-office personnel, community resources, or support groups should be used to help guide patients and provide continual encouragement.

Counseling patience in weight-loss efforts, for example, can help provide more realistic expectations than those given by some popular crash diet programs. Diets must also conform to patient preference and ability to maintain the program. Urging patients to blend more physical activity into their daily routines and engage in forms of exercise they would most enjoy, such as group activities or team sports for social types and individual forms for more solitary people, can also make a difference.

Informing patients of the likely health benefits can also be a prime motivator. People who have HT that has been controlled to normal levels are still at higher risk of CVD and stroke than those who have always been normotensive. The promise of avoiding lifelong dependency on antihypertensive drugs, decreasing their usage, or eliminating the need for them can also be compelling. The broad health benefits of nondrug BP therapies—looking and feeling better, in addition to preventing numerous diseases, from CVD to diabetes to various cancers—make these approaches eminently reasonable and leave little reason not to try them.

REFERENCES

This article was written by Larry Deblinger based on individual interviews with the article consultants.