Hypertension: need for a holistic approach for global control and prevention

Dr. Amrish Saxena*

Hypertension (HTN) is a common lifestyle disorder and is a very strong risk factor for cardiovascular diseases (CVDs). Globally, hypertension exerts a substantial public health burden on cardiovascular health status and healthcare systems.[1] Approximately one-third of adults after age 25 and older have HTN. Worldwide, the estimated number of adults with hypertension was 972 million in 2000; 639 million live in developing countries.[1] By 2025, the total number is expected to increase to 1·56 billion. Approximately 7.6 million deaths (13–15% of the total) and 92 million disability-adjusted life years worldwide were attributable to high blood pressure in 2001.[2] Hypertension doubles the risk of cardiovascular diseases, including coronary heart disease (CHD), congestive heart failure (CHF), ischemic and hemorrhagic stroke, renal failure, and peripheral arterial disease. HTN is directly responsible for 57% of all stroke deaths and 24% of all CHD deaths in India.[3]
Defining Hypertension
Current clinical criteria for defining hypertension generally are based on the average of two or more seated blood pressure readings during each of two or more outpatient visits. A recent classification recommends blood pressure criteria for defining normal blood pressure, prehypertension, hypertension (stages I and II), and isolated systolic hypertension, which is a common occurrence among the elderly (Table 1).[4] HTN in adults aged 18 years and older who are not acutely ill, is defined as “systolic BP of 140 mm Hg or greater and /or diastolic BP of 90 mm Hg or greater or any level of BP in patients taking antihypertensive medication”.

Table 1:  Blood Pressure Classification

Blood Pressure Classification

Systolic, mmHg

Diastolic, mmHg

Normal

<120

and  <80

Prehypertension

120–139

or  80–89

Stage 1 hypertension

140–159

or  90–99

Stage 2 hypertension

≥160

or  ≥100

Isolated systolic hypertension

≥140

and  <90

Primary HTN (Essential HTN):

  • accounts for 85% of the cases
  • not possible to define a specific underlying cause
  • 70% of them have a positive family history.

Secondary HTN:

  • accounts for 15% of the cases
  • consequence of a specific disease or abnormality (renal causes, endocrinal causes, coarctation of aorta, drugs, obstructive sleep apnea etc.)

Pathogenesis — Maintenance of arterial blood pressure is necessary for organ perfusion. In general, the arterial blood pressure is determined by the following equation:
Blood Pressure (BP) = Cardiac Output (CO) x Systemic Vascular Resistance (SVR)
Blood pressure reacts to changes in the environment to maintain organ perfusion over a wide variety of conditions. The primary factors determining the blood pressure are the sympathetic nervous system, the renin-angiotensin-aldosterone system, and the plasma volume (largely mediated by the kidneys).
The pathogenesis of primary hypertension (formerly called "essential" hypertension) is poorly understood but is most likely the result of numerous genetic and environmental factors that have multiple compounding effects on cardiovascular and renal structure and function. HTN, puts a steady strain on blood vessels, resulting in damage that may cause them to narrow and harden with plaque. It raises the risk that vessels will break or that clots will form, break loose and cut off circulation to the brain, resulting in a stroke or block blood flow to the heart, causing a heart attack.
Risk factors for primary (essential) hypertension — Although the exact etiology of primary hypertension remains unclear, a number of risk factors are strongly and independently associated with its development, including:
Age – Advancing age is associated with increased blood pressure, particularly systolic blood pressure, and an increased incidence of hypertension.
Obesity – Obesity and weight gain are major risk factors for hypertension and are also determinants of the rise in blood pressure that is commonly observed with aging. [5,6]
Family history – Hypertension is about twice as common in subjects who have one or two hypertensive parents, and multiple epidemiologic studies suggest that genetic factors account for approximately 30 percent of the variation in blood pressure in various populations. [7]
Race – Hypertension tends to be more common, be more severe, occur earlier in life, and be associated with greater target-organ damage in blacks. [8]
High-sodium diet – Excess sodium intake (eg, >3000 mg/day) increases the risk for hypertension. [9]
Excessive alcohol consumption – Excess alcohol intake is associated with the development of hypertension. [10,11] Patients who have more than two drinks per day have a 1.5 to 2-fold increase in the incidence of hypertension compared to nondrinkers; this effect is dose-related and is most prominent when intake exceeds five drinks per day.
Physical inactivity – Physical inactivity increases the risk for hypertension, and exercise is an effective means of lowering blood pressure.[12]
Diabetes and dyslipidemia – are associated with an increased risk of developing hypertension.[13]

  • Investigations:
    Routine investigations of the hypertensive patient should include:
  • chest X- ray
  • ECG
  • Echocardiogram
  • Urinalysis
  • Fasting blood for lipids and glucose
  • Serum urea, creatinine and electrolytes.

    Management:
    Treatment of hypertension should involve nonpharmacologic therapy (lifestyle modifications) alone or in concert with antihypertensive drug therapy. Unless the patient has severe or malignant hypertension, there should be a period of assessment with repeated blood pressure measurements, combined with advice and non-pharmacological measures prior to the initiation of drug therapy. The primary goal of therapy of hypertension is effective control of BP to prevent, reverse or delay the progression of complications, and thus reduce the overall risk of an individual without affecting the quality of life.
    Management of hypertension should proceed as follows:

    • In low risk patients, institute lifestyle modifications, and observe BP for a period of 3 months before deciding whether to initiate drug therapy or not.
    • In medium risk patients, institute lifestyle modifications and monitor BP on a monthly basis. If after a period of 3 months, BP remains above 140/90 mm Hg then initiate drug therapy.
    • In high risk group, use lifestyle modification therapy with drug therapy forthwith.
    • In very high risk patients, initiate immediate drug treatment for hypertension and other risk factors.

    If BP rises to levels consistently >20/10 mm Hg above goal during this treatment period of low/ medium risk patients or BP remains >140/90 mm Hg, appropriate pharmacological therapy should be started at that time.


    Nonpharmacologic therapy  (Lifestyle Interventions):
    Implementation of lifestyles that favorably affect blood pressure has implications for both the prevention and the treatment of hypertension. Health-promoting lifestyle modifications are recommended for individuals with prehypertension and as an adjunct to drug therapy in hypertensive individuals.
    The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure recommends 5 lifestyle changes for all patients with hypertension: reducing sodium intake, increasing exercise, moderating alcohol consumption, losing weight, and following the Dietary Approaches to Stop Hypertension (DASH) eating plan (Table 2).[4]


    Table 2:  Lifestyle Modifications to Manage Hypertension

    Weight reduction

    Attain and maintain BMI <25 kg/m2 

    Dietary salt reduction

    Reduce dietary sodium intake to no more than 100 meq/day (2.4 g sodium or 6 g sodium chloride)

    Adapt DASH-type dietary plan

    Diet rich in fruits, vegetables, and low-fat dairy products with reduced content of saturated and total fat

    Moderation of alcohol consumption

    For those who drink alcohol, consume 2 drinks/day in men and 1 drink/day in women

    Physical activity

    Regular aerobic activity, e.g., brisk walking for 30 min/day

     

    • Dietary salt restriction – In well-controlled randomized trials, the overall impact of moderate sodium reduction is a fall in blood pressure in hypertensive and normotensive individuals of 4.8/2.5 and 1.9/1.1 mmHg, respectively.[9,14,15] Dietary NaCl reduction also has been shown to reduce the long-term risk of cardiovascular events in adults with "prehypertension”. Daily dietary sodium intake should be reduced to no more than 100 meq/day (2.4 g sodium or 6 g sodium chloride).
    • Weight loss – Weight loss in overweight or obese individuals can lead to a significant fall in blood pressure independent of exercise. [15] The weight loss-induced decline in blood pressure generally ranges from 0.5 to 2 mmHg for every 1 kg of weight lost.
    • Dietary Approaches to Stop Hypertension (DASH) diet – The DASH dietary pattern is high in vegetables, fruits (at least 300 g of fruit and vegetables a day), low-fat dairy products, whole grains, poultry, fish, and nuts; and low in sweets, sugar-sweetened beverages, and red meats. The DASH dietary pattern is consequently rich in potassium, magnesium, calcium, protein, and fiber, but low in saturated fat, total fat, and cholesterol. A trial in which all food was supplied to normotensive or mildly hypertensive adults found that the DASH dietary pattern reduced blood pressure by 6/4 mmHg compared with typical American-style diet that contained the same amount of sodium and the same number of calories. Combining the DASH dietary pattern with modest sodium restriction produced an additive antihypertensive effect. [14,16]
    • Exercise – Dynamic aerobic exercise (walking, jogging, cycling or swimming) on 5 to 7 days a week, and possibly resistance training, can decrease systolic and diastolic pressure by, on average, 4 to 6 mmHg and 3 mmHg, respectively, independent of weight loss. Most studies demonstrating a reduction in blood pressure have employed three to four sessions per week of moderate-intensity aerobic exercise lasting approximately 40 minutes for a period of 12 weeks. [17]
    • Limited alcohol intake – Women who consume two or more alcoholic beverages per day and men who have three or    more drinks per day have a significantly increased incidence of hypertension compared with nondrinkers; this effect is   dose related and is most prominent when intake exceeds five drinks per day.[5] Alcohol consumption should be limited to no more than 2 drinks per day in most men and no more than 1 drink per day in women and lighter-weight persons.
    • Stress reduction - avoiding sources of stress, where possible, and developing healthy coping strategies for managing unavoidable stress can help with blood pressure control

    In addition, insistence on cessation of smoking is mandatory in order to improve CV risk, and because cigarette smoking has an acute pressor effect that may raise daytime ambulatory BP. [18]

Other non-pharmacologic approaches: There are many different types of complementary and alternative treatments found to be effective for treating HTN. Evidence for use in hypertension exists for slow breathing techniques, Qigong (incorporates movement, breathing, and meditation), meditation and relaxation techniques such as yoga, and coenzyme Q10 (Table 3). [19,20,21,22] Slow, controlled breathing can increase parasympathetic and decrease sympathetic nervous system activity, which are important factors in controlling BP.[23,24] Transcendental meditation is a form of meditation in which the practitioner sits twice daily with eyes closed and repeats a mantra in a prescribed manner. A meta-analysis of 9 RCTs found a reduction of 4.7 mm Hg (95% CI 7.4 to 1.9 mm Hg) in systolic BP and 3.2 mm Hg (95% CI 5.4 to 1.3 mm Hg) in diastolic BP.[25] While the evidence supporting these CAM interventions is not as robust as that for pharmacotherapy, this should be considered in the context of the limitations of evidence-based medicine.

Table 3:  Class of Recommendation and Level of Evidence of various additional/complementary therapies for Blood Pressure Lowering:


Additional/Complementary Therapies

LOE

COR

Behavioral therapies

Transcendental Meditation

B

IIB

Other meditation techniques

C

III

Biofeedback approaches

B

IIB

Yoga

C

III

Other relaxation techniques

B

III

Noninvasive procedures or devices

Acupuncture

B

III

Device-guided breathing

B

IIA

Exercise-based regimens

Dynamic aerobic exercise

A

I

Dynamic resistance exercise

B

IIA

Isometric  hand grip exercise

C

IIB

   COR indicates class of recommendation; and LOE, level of evidence

Pharmacologic Therapy
Drug therapy is recommended for individuals with blood pressures ≥ 140/90 mmHg. The degree of benefit derived from antihypertensive agents is related to the magnitude of the blood pressure reduction. Lowering systolic blood pressure by 10–12 mmHg and diastolic blood pressure by 5–6 mmHg confers relative risk reductions of 35–40% for stroke and 12–16% for CHD within 5 years of the initiation of treatment. Risk of heart failure is reduced by >50%.
In diabetic patients, effective blood pressure control reduces the risk of cardiovascular events and death as well as the risk for microvascular disease (nephropathy, retinopathy).
Selection of antihypertensive agents and combinations of agents should be individualized, taking into account age, severity of hypertension, other cardiovascular disease risk factors, comorbid conditions, and practical considerations related to cost, side effects, and frequency of dosing.
Based on pooling results from clinical trials, meta-analyses of the efficacy of different classes of antihypertensive agents suggest essentially equivalent blood pressure–lowering effects of the following six major classes of antihypertensive agents when used as monotherapy: thiazide diuretics, beta blockers, angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), calcium antagonists, and alpha 2- blockers. On average, standard doses of most antihypertensive agents reduce blood pressure by 8–10/4–7 mmHg; however, there may be subgroup differences in responsiveness. Younger patients may be more responsive to beta blockers and ACEIs, whereas patients over age 50 may be more responsive to diuretics and calcium antagonists.


Conclusion:
The management of HTN needs to be addressed in a complementary fashion (Non-pharmacological- lifestyle modifications, complementary and alternative treatments, pharmacotherapy) requiring a patient-centered and multi-factorial approach. However, targets need to be individualized. Management strategies should be considered in the context of the individual’s characteristics, and decisions regarding their use should be made with the individual. Integrative medical approach to HTN by combining standard medical treatments with alternative therapies provides a balanced and customized treatment plan for hypertensive patients.

References:

1.     Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, et al. (2005) Global burden of hypertension: analysis of worldwide data. Lancet 365: 217-223.
2.     Lawes CM, Vander Hoorn S, Rodgers A (2008) Global burden of blood-pressure-related disease, 2001. Lancet 371: 1513-1518.
3.     Gupta R (2004) Trends in hypertension epidemiology in India. J Hum Hypertens 18: 73-78.
4.     Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, et al. (2003) Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension 42: 1206-1252.
5.     Forman JP, Stampfer MJ, Curhan GC (2009) Diet and lifestyle risk factors associated with incident hypertension in women. JAMA 302: 401-411.
6.     Sonne-Holm S, Sorensen TI, Jensen G, Schnohr P (1989) Independent effects of weight change and attained body weight on prevalence of arterial hypertension in obese and non-obese men. BMJ 299: 767-770.
7.     Wang NY, Young JH, Meoni LA, Ford DE, Erlinger TP, et al. (2008) Blood pressure change and risk of hypertension associated with parental hypertension: the Johns Hopkins Precursors Study. Arch Intern Med 168: 643-648.
8.     Berenson GS, Chen W, Dasmahapatra P, Fernandez C, Giles T, et al. (2011) Stimulus response of blood pressure in black and white young individuals helps explain racial divergence in adult cardiovascular disease: the Bogalusa Heart Study. J Am Soc Hypertens 5: 230-238.
9.     He FJ, Li J, Macgregor GA (2013) Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ 346: f1325.
10. (1988) Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. Intersalt Cooperative Research Group. BMJ 297: 319-328.
11.  Fuchs FD, Chambless LE, Whelton PK, Nieto FJ, Heiss G (2001) Alcohol consumption and the incidence of hypertension: The Atherosclerosis Risk in Communities Study. Hypertension 37: 1242-1250.
12.  Carnethon MR, Evans NS, Church TS, Lewis CE, Schreiner PJ, et al. (2010) Joint associations of physical activity and aerobic fitness on the development of incident hypertension: coronary artery risk development in young adults. Hypertension 56: 49-55.
13. de Simone G, Devereux RB, Chinali M, Roman MJ, Best LG, et al. (2006) Risk factors for arterial hypertension in adults with initial optimal blood pressure: the Strong Heart Study. Hypertension 47: 162-167.
14. Appel LJ, Brands MW, Daniels SR, Karanja N, Elmer PJ, et al. (2006) Dietary approaches to prevent and treat hypertension: a scientific statement from the American Heart Association. Hypertension 47: 296-308.
15. Whelton PK, Appel LJ, Espeland MA, Applegate WB, Ettinger WH, Jr.,et al.(1998) Sodium reduction and weight loss in the treatment of hypertension in older persons: a randomized controlled trial of nonpharmacologic interventions in the elderly (TONE). TONE Collaborative Research Group. JAMA 279: 839-846.
16. Sacks FM, Campos H (2010) Dietary therapy in hypertension. N Engl J Med 362: 2102-2112.
17.  Stewart KJ, Bacher AC, Turner KL, Fleg JL, Hees PS, et al. (2005) Effect of exercise on blood pressure in older persons: a randomized controlled trial. Arch Intern Med 165: 756-762.
18. Mann SJ, James GD, Wang RS, Pickering TG (1991) Elevation of ambulatory systolic blood pressure in hypertensive smokers. A case-control study. JAMA 265: 2226-2228.
19. Nahas R (2008) Complementary and alternative medicine approaches to blood pressure reduction: An evidence-based review. Can Fam Physician 54: 1529-1533.
20. Wang J, Xiong X, Liu W (2013) Yoga for essential hypertension: a systematic review. PLoS One 8: e76357.
21. Hagins M, States R, Selfe T, Innes K (2013) Effectiveness of yoga for hypertension: systematic review and meta-analysis. Evid Based Complement Alternat Med 2013: 649836.
22. Brook RD, Appel LJ, Rubenfire M, Ogedegbe G, Bisognano JD, et al. (2013) Beyond medications and diet: alternative approaches to lowering blood pressure: a scientific statement from the american heart association. Hypertension 61: 1360-1383.
23. Grossman E, Grossman A, Schein MH, Zimlichman R, Gavish B (2001) Breathing-control lowers blood pressure. J Hum Hypertens 15: 263-269.
24. Mourya M, Mahajan AS, Singh NP, Jain AK (2009) Effect of slow- and fast-breathing exercises on autonomic functions in patients with essential hypertension. J Altern Complement Med 15: 711-717.
25. Anderson JW, Liu C, Kryscio RJ (2008) Blood pressure response to transcendental meditation: a meta-analysis. Am J Hypertens 21: 310-316.


Dr Amrish Saxena is presently working as Associate Professor, Dept of Medicine at MGIMS. He underwent dialysis training in the department of Nephrology at Care Hospital, Nampally, Hyderabad and is heading the haemodialysis unit in the department of Medicine. He has interests in integrative medicine to reduce drugs and help patients with holistic healthcare.

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