Hypertension is a major risk factor for multiple cardiovascular diseases, including coronary artery disease, stroke, end-stage renal disease, and peripheral vascular disease. The World Health Organization estimates that nearly one-third of worldwide deaths are due to hypertension.[1] Hypertension, obesity, insulin resistance, and lipid abnormalities (hypertriglyceridemia and low levels of high-density lipoprotein [HDL]-cholesterol) make up the metabolic syndrome, a particularly virulent risk profile for cardiovascular disease.
About 78 million people in the United States have hypertension. Because it is typically asymptomatic, about 20% of hypertensive persons are unaware of their disease, and only about half of those who are aware achieve adequate blood pressure control.[2] Severe cases may be marked by headache, vision changes, and nausea and vomiting.
Most cases are referred to as primary or essential, meaning that no specific medical cause has been identified (although diet, obesity, and other controllable factors contribute to essential hypertension). Approximately 5-10% of cases are secondary; that is, they have an identifiable contributing factor, such as renal or renovascular disease, endocrine pathology, obstructive sleep apnea, or prescription and over-the-counter medications.
Black Americans have a higher prevalence of hypertension compared with African Black individuals and North American White individuals.
The following factors increase the likelihood of developing hypertension:
Age. About two-thirds of Americans over age 65 have high blood pressure.
Family history. As much as 30% of variation in blood pressure may be a consequence of genetic factors.
Obesity. The prevalence of hypertension in overweight adults is doubled compared with individuals near their ideal weight. In addition, overweight is often associated with sleep apnea, which is also associated with increased risk of hypertension.
Lack of exercise. In Western populations, physical inactivity contributes an estimated 5-13% of the risk for hypertension.[3] Moreover, worldwide it is estimated that 6% of the burden of heart disease (of which hypertension is a major risk factor) is attributable to physical inactivity.[4]
Dietary factors are discussed in Nutritional Considerations below.
Renal disease.
Endocrine disease. Hyperaldosteronism, thyroid disorders, hyperparathyroidism, Cushing’s syndrome, and pheochromocytoma are among the endocrine causes of hypertension.
Alcohol excess.
Medications. Corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), antihistamines, diet pills, oral contraceptives, and some antidepressants can increase blood pressure.
Sustained and untreated high blood pressure may lead to end-organ damage, including coronary artery disease, left ventricular hypertrophy, heart failure (hypertension is the leading cause in developed countries), stroke, retinopathy, and kidney disease. Early diagnosis and treatment are therefore important.
Normal blood pressure is defined as < 120/80 mmHg. Elevated blood pressure is defined as a blood pressure 120-129 over < 80 mmHg. Stage 1 hypertension is defined as a systolic blood pressure measurement of 130-139 mmHg or a diastolic measurement of 80-89 mmHg. Stage 2 hypertension is defined as a systolic measurement ≥ 140 mmHg or a diastolic measurement ≥ 90 mmHg.[5] Although the above categories are defined by the higher systolic or diastolic measurement, systolic pressures correlate more strongly with cardiovascular disease risk.
Hypertension accompanied by evidence of acute end-organ dysfunction, such as a cerebrovascular accident, a myocardial infarction, pulmonary edema, encephalopathy, or acute kidney injury, is termed hypertensive emergency and requires blood pressure lowering within minutes to hours.[6] Evidence of end-organ damage can rapidly develop in patients with previously normal blood pressure. Severely elevated blood pressure without evidence of acute end-organ damage is termed hypertensive urgency and requires blood pressure lowering over hours to days in an outpatient setting.[7]
Diagnostic evaluation should consider possible causes of hypertension and its sequelae. Abnormal history or physical examination findings should guide cost-effective testing. Routine laboratory testing and procedures include an electrocardiogram, lipid profile, urinalysis, hematocrit, and a basic metabolic panel. Lipid goals are based on a cardiovascular risk factor assessment.
Children with hypertension should be evaluated for coarctation of the aorta or renal pathology.
According to the 2017 American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, goal blood pressure for most individuals with hypertension, including those with diabetes or chronic kidney disease, is < 130/80 mmHg.[5]
Lifestyle modifications are an integral initial step in the treatment of hypertension. These may include a low-sodium, low-fat diet (particularly a low-fat vegan diet, as noted below), maintenance of appropriate body weight, reduction in alcohol use, increased physical activity, and possibly stress reduction (e.g., through meditation or yoga). Energy expenditure in the form of moderate to vigorous activity reduces risk of hypertension by 10-20%.[8] Even walking and leisure-time physical activity also lower the risk for developing hypertension.[9] Smoking cessation does not treat hypertension but should be encouraged for cardiovascular and other health-risk reduction.
Elevated blood pressure usually does not require drug therapy unless the patient has higher cardiovascular risk, has significantly elevated high blood pressure, or has coronary heart disease, diabetes, heart failure, chronic kidney disease, history of stroke, or other end-organ damage.
Pharmacologic therapy includes several drug choices. Individuals with inadequate response to single-drug treatment often respond to another drug class. However, most patients require at least 2 drugs to achieve target blood pressure, and the use of 3 or more drugs is common.
A thiazide diuretic, calcium channel blocker or angiotensin-converting enzyme inhibitor (ACEI), or angiotensin receptor blocker (ARB) is usually prescribed as first-line pharmacotherapy in the general non-Black population, including those with diabetes. For Black patients, including those with diabetes, a thiazide or calcium channel blocker is the usual first-line treatment.[8]
Racial differences in response to hypertensive therapy have been noted. In Black patients, a calcium channel blocker was found to be more effective at controlling blood pressure than an ACEI in some studies. In addition, regardless of the presence or absence of diabetes, a thiazide resulted in improved cardiovascular outcomes compared with an ACEI, and the risk of stroke is significantly reduced with use of a calcium channel blocker, compared with an ACEI.[10][11]
Specific details of each drug class are listed below. Drugs from these classes can be used alone (for specific protective functions) or in combination.
Thiazide diuretics are inexpensive. They tend to reduce calciuria, an effect that may be beneficial for those at risk for osteoporosis and calcium stones. Thiazides may increase blood glucose and lipids.
Angiotensin-converting enzyme inhibitor (ACEIs) are advantageous in patients after myocardial infarction and in those who have proteinuria or systolic heart failure. They may also be advantageous in diabetes but are contraindicated in pregnant women. Side effects include cough, hyperkalemia, and rarely, angioedema.
Beta-blockers serve as optimal treatment after myocardial infarction. They are also used for systolic heart failure, atrial fibrillation, and angina, and they are safe in pregnancy. However, beta-blockers should be avoided in patients with reactive airway disease or second-degree or third-degree heart block. Erectile dysfunction is a common side effect.
Angiotensin receptor blockers (ARBs) have benefits similar to those of ACEIs. Patients with side effects from ACE inhibitors may be switched to ARBs. These two classes should not be combined as doing so increases the risk for adverse effects and has not been shown to improve mortality. Like ACE inhibitors, ARBs may cause hyperkalemia and are contraindicated in pregnancy.
Calcium channel blockers help protect against angina, and non-dihydropyridine calcium channel blockers may be used for heart rate control. Calcium channel blockers may cause pedal edema and/or conduction abnormalities.
Alpha-adrenergic blockers (e.g., tamsulosin) are indicated in patients with concomitant benign prostatic hyperplasia because of their vasodilatory action on both blood vessels and prostatic smooth muscle. They are associated with risk of postural hypotension but are safe in pregnancy.
Arterial vasodilators include specific drugs that have noteworthy side effects. Hydralazine may cause lupus syndrome, but it is safe in pregnancy.
Minoxidil may cause sodium (i.e., water) retention. It can also cause some degree of hair regrowth, which may be advantageous in balding men.
Potassium-sparing diuretics are optimal for patients at risk of hypokalemia or those with some degree of hyperaldosteronism, which would lower serum potassium. In either scenario, close monitoring of potassium levels is required.
People with hypertension often have lower melatonin levels compared with those with normal blood pressure, and some fail to experience the normal nocturnal decrease in blood pressure.[12][13] Although melatonin supplementation may lead to lower nocturnal blood pressures, it is not currently recommended due to a lack of data showing improved outcomes.
Nutritional factors play a large role not only in reducing the risk that hypertension will occur but also in managing the condition after it has been diagnosed. The Dietary Approaches to Stop Hypertension (DASH) studies showed that diets rich in fruits and vegetables and reduced in meat and saturated fat can both lower the risk for high blood pressure and assist with blood pressure control in hypertensive persons.[14][15] The DASH study was predicated on the observation that vegetarian diets are associated with markedly reduced risk of hypertension. Vegetables and fruits accounted for approximately half of the blood-pressure-lowering effect of the diet. Restricting sodium intake enhanced the blood-pressure-lowering effect. While the DASH diet reduced systolic blood pressure by 5-6 mmHg, individuals eating the DASH diet in combination with the lowest sodium intake (1,200 mg/day) had a further blood pressure decrease of 5-8 mmHg.[16]
Specific factors influencing blood pressure include the following:
Weight loss. A Cochrane review of 8 randomized controlled trials reported that participants following weight-reduction diets reduced their blood pressure by a mean of 4.5 mmHg systolic and 3.2 mmHg diastolic.[17] Although a reduction in plasma volume is the most likely reason, this effect may also be in part due to a 15% lower activity of angiotensin-converting enzyme after weight loss.[18]
Vegan and vegetarian diets. Numerous studies have linked beef, veal, lamb, poultry, and animal fat to high blood pressure.[19][20][21][22] Part of the problem is that saturated fat influences blood viscosity.[23] Vegetarians, especially vegans, have lower blood pressure, even when body mass index is controlled for.[24] Eliminating animal products reduces blood pressure in both normotensive and hypertensive individuals and has the potential to reduce or eliminate medication use in some patients.[25]
Plant proteins are higher in L-arginine (an amino acid involved in production of nitric oxide) compared with animal protein, and intake of vegetable (not animal) protein is inversely related to blood pressure.[26] A number of studies have found that soy protein supplementation reduces blood pressure in both normotensive and hypertensive individuals.
Limiting sodium. Hypertension is rare in societies in which dietary sodium intake is very low.[27][28] A 2004 meta-analysis of contributors to hypertension in Finland, Italy, the Netherlands, the United Kingdom, and the US found that 9-17% of the risk for hypertension was attributable to dietary sodium alone.[29] The principal sources of sodium are canned foods, snack foods, discretionary use of salt in food preparation or consumption, and dairy products. In their natural state, vegetables, fruits, grains, and legumes are very low in sodium. A crossover trial found that after just 1 week, when participants ate a low-sodium diet (500 mg/day), blood pressure was 8 mmHg lower than when they ate a high-sodium diet (an added 2,200 mg of sodium per day on top of their usual diet).[30]
Increasing potassium intake. Potassium is an electrolyte that reduces blood pressure and stroke risk through improved vasodilation.[31][32] Beet greens, Swiss chard, spinach, potatoes, tomato paste, and adzuki beans are excellent sources.
Emphasizing nitrate-rich vegetables. Evidence suggests that some vegetables may lower blood pressure by providing antioxidant flavonoids that up-regulate endothelial nitric oxide production and by suppressing enzymes involved in the generation of superoxide radicals that are known to reduce nitric oxide availability.[33][34][35] Arugula is especially nitrate rich; cilantro, rhubarb, butterleaf lettuce, and other leafy greens are also excellent sources.
Drinking tea. Hibiscus tea, which is rich in antioxidants and anthocyanins, reduced systolic blood pressure by a mean of 7.6 mmHg and diastolic pressure by 3.5 mmHg in a meta-analysis of 5 randomized controlled trials.[36] Another meta-analysis with green and black tea found long-term (> 12 weeks) consumption significantly reduced systolic and diastolic pressure.[37]
Adding seeds. Both flaxseed and chia seeds, high in fiber and omega-3 fatty acids, have been found to lower blood pressure in randomized controlled trials. Hypertensive individuals who consumed 30 g of ground flaxseed daily for 6 months had systolic and diastolic blood pressures fall, on average, by 15 mmHg and 7 mmHg, respectively.[38] Average systolic blood pressure normalized, falling from 132 mmHg to 119 mmHg, among individuals with diabetes who were assigned to a treatment group that ingested 40 g of chia seeds daily for 12 weeks.[39]
Choosing whole grains. A randomized controlled study with healthy individuals found that 3 servings of whole grains reduced systolic and diastolic pressure by 6 mmHg and 3 mmHg, respectively.[40] Large prospective studies support the evidence that whole grain consumption reduces blood pressure and hypertension risk.[41]
Additional considerations in preventing or controlling hypertension include:
Limiting alcohol. Beyond moderate consumption (1-2 drinks/day), alcohol intake raises the risk for developing hypertension.[29] Avoiding alcohol reduces systolic blood pressure.[17] The relationship between moderate alcohol intake and hypertension is complicated, however. Studies have found a lower risk for hypertension-related mortality in moderate drinkers, even in those with hypertension, compared with persons who rarely or never drink alcohol.[28][29]
Folic acid. The Nurses’ Health Study found that women consuming the highest amounts of folate from diet and supplements (≥ 1000 μg per day) had only one-third the risk for developing hypertension, compared with women consuming less than 200 μg per day.[26] One possible explanation is that folate is an important cofactor for nitric oxide synthase and subsequent nitric oxide generation.
Vitamin C. Higher vitamin C intakes are associated with lower blood pressure.[42][43][44] However, there do not appear to be any additional blood-pressure-lowering effects of vitamin C over an intake of 500 mg per day.
Magnesium. Magnesium helps moderate blood pressure, competes with sodium for binding sites on vascular smooth muscle cells, and reduces endothelial dysfunction in hypertensive patients.[45] Some studies have shown that magnesium intake is inversely associated with blood pressure and could play a significant role in prevention.[46][47] The Women’s Health Study of more than 28,000 women found that the highest magnesium intakes (434 mg/day) were associated with a 7% lower risk for developing hypertension, compared with intakes of 256 mg/day.[48] Evidence on the efficacy of supplementation is mixed though magnesium appears to be most beneficial when combined with a high-potassium, low-sodium diet.[45][49][50][51] Spinach, Swiss chard, and legumes are low-sodium, high-potassium sources of magnesium.
See Basic Diet Orders chapter.
Sodium limitation.
Smoking cessation and alcohol restriction, if applicable.
Individualized exercise prescription, as appropriate.
Hypertension usually has no symptoms but can be deadly. It is important for the patient and the family to have their blood pressure checked regularly and to adhere to the prescribed treatment plan. A good-quality home blood pressure monitor provides a convenient means of tracking hypertension and progress with treatment.
Hypertension is not treated with medication alone. Dietary and lifestyle changes can significantly help reduce blood pressure and can reduce, sometimes even eliminate, the need for medication. The family can support and enhance the patient’s adherence to the recommended diet. Because weight problems and hypertension often run in families, it is important for the entire family to shift to healthier eating and exercise patterns. Smoking cessation and alcohol restriction should be encouraged.
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