Prehypertension

What is Prehypertension?

Hypertension, also known as high blood pressure, is a key risk for heart diseases. In fact, it is the modifiable factor that causes the greatest number of deaths in the US. Studies have indicated that as your blood pressure increases, your risk of getting these diseases goes up. Specifically, every time you add 20 mm Hg to your systolic (top number) blood pressure or 10 mm Hg to your diastolic (bottom number) blood pressure, you’re doubling your risk of dying from a stroke, heart disease, or other blood vessel-related diseases.

In 2003, the term “prehypertension” was introduced in America, referring to individuals having a systolic blood pressure between 120 and 139 mm Hg or a diastolic blood pressure between 80 and 89 mm Hg. Yet, recent studies reveal that adults who fall under this range are twice as likely to experience heart diseases or deaths, as compared to adults with normal blood pressure. Shockingly, this group of “prehypertensive” patients accounts for over 20% of blood pressure-related heart problems.

However, the 2017 guidelines by the American College of Cardiology / American Heart Association redefine blood pressure groupings. The term “prehypertension” is eliminated. Instead, blood pressure is classified as normal (less than 120/80 mm Hg), elevated (120-129/<80 mm Hg), stage 1 hypertension (130-139 mm Hg systolic or 80-89 mm Hg diastolic), and stage 2 hypertension (140 mm Hg systolic or 90 mm Hg diastolic). These guidelines highlight that a person's risk of heart disease progressively rises from normal blood pressure to elevated blood pressure and stage 1 hypertension, which would've been referred to as "prehypertensive" in the past.

This article discusses the reclassification of formerly “prehypertensive” patients into the new elevated blood pressure or stage 1 hypertension categories. It provides treatment advice for these individuals, to help doctors adjust their treatment plans and enhance patient health outcomes.

What Causes Prehypertension?

High blood pressure, which can range from prehypertension to stage 1 hypertension, can be caused by many factors. The exact triggers for essential or primary hypertension – the most common type – are not fully understood, but we do know of several key risk factors.

Age is a big factor that can’t be changed. Studies show that the risk of high blood pressure increases with age, with a 0.3% likelihood at age 25, 6.5% at age 45, and up to 37% at 65 years of age.

Genetics also play a part. If your family has a history of high blood pressure, your chances of developing it are higher. One lengthy study found that having both parents with hypertension could predict high blood pressure in the future. In terms of ethnicity, African Americans and Hispanic Americans were found to have the highest risk (93% and 92%, respectively), followed by Caucasians (86%) and Chinese Americans (84%) by the age of 45.

Obesity is another major risk factor for high blood pressure. There’s a direct link between body mass index and blood pressure. Waist-to-hip ratio is another important factor. A study from China reported that having a large waist size was a separate risk factor for developing high blood pressure. The longer someone has been obese and the younger they were when they started gaining weight also add to the risk.

Diet also plays a significant role. Too much salt in your diet can lead to high blood pressure, as well as increase the risk of stroke and heart-related problems. On the other hand, potassium helps to lower blood pressure and counteract the effect of salt. Drinking too much alcohol can also increase blood pressure.

Physical activity can help lower blood pressure. Even a small increase in activity levels can help.

Secondary hypertension, a less common type, can be caused by many factors, including medications like birth control pills, steroids, and certain types of drugs for colds and allergies. Stimulants and illicit drugs like meth and cocaine can also lead to secondary hypertension. Certain medical conditions, such as kidney failure, sleep apnea, and certain hormone-related diseases, can also cause secondary hypertension.

Risk Factors and Frequency for Prehypertension

According to reports, almost half (46%) of the adult population in the United States suffers from hypertension, marking it as a leading health issue. Notably, hypertension was pinpointed as the top reason for deaths and years lived with disability globally in 2010. In the United States, it’s the major cause of heart-related deaths that can be prevented and the second top cause of avoidable deaths from any cause.

• A shocking 90% of people who are initially free of hypertension at the ages of 55 or 65 are likely to develop it later in life.
• The ratio of people with hypertension can vary depending on how it’s defined. Using the ACC/AHA definition, about 46% of U.S. adults have hypertension, whereas under the JNC 7 definition, it’s estimated around 32%.

Assessing the prevalence and impact of hypertension worldwide is even more challenging. The World Health Organization (WHO) reports that an estimated 1.28 billion adults aged between 30 and 79 are suffering from hypertension globally. This issue is especially prevalent in low and middle income countries, where nearly half (46%) of adults with hypertension remain undiagnosed. According to WHO, only 21% of people diagnosed globally with hypertension manage their condition effectively.

Signs and Symptoms of Prehypertension

Blood pressure (BP) is an essential health measurement. Devices that measure BP automatically are preferred as they are more precise and can avoid human mistakes linked to manual methods. Manual methods are still acceptable when the automatic devices aren’t accessible.

The American College of Cardiology/American Heart Association (ACC/AHA) provides advice for accurate BP measurement and points out common pitfalls. Key steps include ensuring the patient is calm and rested for at least 5 minutes before the measurement and avoiding caffeine, exercise, and smoking 30 minutes prior. A validated, calibrated device and accurately sized cuff should be used. The cuff should be inflated above the level where the pulse can’t be felt, then slowly deflated to determine BP levels. The process needs to be repeated multiple times on separate occasions for an accurate estimate. It’s also important that the patient’s arm is supported at the level of the heart.

Blood pressure can also be monitored outside the clinic: at home or using an ambulatory monitor (a device worn for a set duration). These methods can uncover patients with hidden high BP or those who only have high BP at the doctor’s office. Monitoring is highly recommended in patients with a known or suspected condition, especially those with newly diagnosed and elevated BP levels.

Wearing an ambulatory monitor for a 24 to 48-hour period is the gold standard for external BP assessment. If a 24-hour period isn’t possible, a 6 to 8-hour period should suffice. The device records average BP levels during the day and night. High blood pressure is defined as having an average BP level higher than certain figures indicated by medical guidelines.

The most accurate BP measurements are taken at the arm. Both arms should be checked initially, but more measurements should be done on the arm that produces higher BP readings. If arm measurements aren’t possible, BP can be measured at the lower leg or wrist, though these methods aren’t as precise.

• Relax and rest for at least 5 minutes
• Avoid caffeine, exercise, and smoking 30 mins prior
• Use a calibrated, validated device
• Ensure cuff fits correctly and use it properly
• Arm supported and at heart level during the measurement
• Measure BP multiple times and on separate occasions
• Supplement with home or ambulatory monitoring for suspected patients
• Measure BP on both arms initially, then focus on the arm with higher BP

After diagnosing high blood pressure, a thorough examination should be carried out to identify the possible cause, which could be related to lifestyle factors such as diet, physical inactivity, alcohol consumption, and tobacco use, or may indicate other health conditions.

• Unstable BP and episodes of dizziness/paleness hint at a condition called pheochromocytoma)
• Snoring and excessive sleepiness may point to obstructive sleep apnea
• Cramps, weakness, and signs suggesting low potassium could indicate primary or secondary aldosteronism
• Weight loss, palpitations, and heat intolerance might hint at hyperthyroidism
• Swelling, fatigue, and frequent urination could suggest kidney disease or failure
• Obesity centered around the abdomen, rounded face, and bruising easily may be signs of Cushing syndrome

Testing for Prehypertension

The World Health Organization (WHO) advises that patients with high blood pressure should undergo laboratory tests to check for any related health conditions or underlying causes. If possible and without delaying high blood pressure treatment, doctors should order tests to examine:

* Levels of different substances in the blood, including electrolytes and creatinine
* Fat levels in the blood – also known as a lipid panel
* Levels of hemoglobin A1c or fasting glucose in the blood
* Properties of the patient’s urine
* Electric activity of the patient’s heart by an electrocardiogram

WHO emphasizes that these tests can be expensive, and it’s unsure if the costs are justified in areas with limited resources or if starting treatment immediately is more important.

WHO also suggests assessing cardiovascular risk for patients with high blood pressure at or after the start of treatment, as long as it doesn’t delay therapy. It’s particularly important for patients with mildly raised blood pressure. If these patients show a higher risk of cardiovascular disease, doctors might need to adjust their treatment plan.

The American College of Cardiology and the American Heart Association (ACC/AHA) have similar recommendations. They suggest routine tests for new patients diagnosed with high blood pressure to assess their risk of heart disease and to check for any secondary causes. In addition to the tests recommended by the WHO, the ACC/AHA guidelines also advise optional tests like an echocardiogram (an ultrasound of the heart), levels of uric acid in the blood, and a comparison of the amounts of albumin and creatinine in the urine.

An electrocardiogram, which records the heart’s electrical activity, is especially useful for identifying an enlarged left ventricle (a heart condition known as left ventricular hypertrophy, or LVH). This test can independently forecast heart-related complications in patients. In addition, if the left ventricle’s size decreases, it indicates a lower cardiovascular risk, even if blood pressure levels remain the same.

Treatment Options for Prehypertension

The World Health Organization (WHO) advises starting medication for anyone with high blood pressure, defined as 140/90 mm Hg or higher. This level is referred to as stage 2 hypertension by the ACC/AHA guidelines. Individuals with a systolic blood pressure of 130 to 139 mm Hg, those with heart disease, diabetes, or chronic kidney disease—even if they don’t have heart disease—are also advised to start on medication. The treatment suggested includes drugs like thiazide, angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, and long-acting dihydropyridine calcium channel blockers, which can be used alone or in combination.

The ACC/AHA guidelines similarly recommend that patients classify as having high blood pressure (or in stage 1 hypertension) consult with their healthcare provider in order to understand their 10-year risk for heart disease. Medication should be started for those with a 10-year risk of 10% or higher. For patients over the age of 79, this risk is assumed to be greater than 10%.

Patients with what is considered stage 1 high blood pressure, who have a less than 10% risk of heart disease within the next 10 years, are recommended to start with non-drug therapy and have their blood pressure checked again in 3 to 6 months. If the 10-year risk is 10% or higher, then a combination of medication and non-drug therapy is recommended. In cases of Stage 2 hypertension, treatment should involve a dual approach that combines non-drug therapy and two different classes of medication.

Non-drug interventions are heavily encouraged for patients with high or stage 1 hypertension. These include weight reduction, a healthy diet, less sodium, more dietary potassium (unless the patient has kidney problems), and increased exercise. Quitting or limiting alcohol intake is also recommended. Out of all the dietary plans available, the DASH (Dietary Approaches to Stop Hypertension) diet is the one acknowledged by the ACC/AHA as having strong evidence of efficacy.

Other non-drug interventions, such as consuming probiotics, garlic, dark chocolate, coffee, protein, flaxseed, or fish oil, taking calcium or magnesium supplements, following dietary plans other than the DASH diet, stress reduction, and behavioral therapies (like guided breathing, yoga, meditation, and biofeedback), may help decrease blood pressure, but they don’t have as much support in the current guidelines.

Patients with high blood pressure are likely to see similar benefits from weight loss as those with an official diagnosis of hypertension. For every kilogram lost, blood pressure typically improves by 1 mm Hg. The DASH diet, which emphasizes fruits, vegetables, and low-fat dairy, can help to reduce blood pressure in both hypertensive and normal patients. This is further improved with sodium reduction and lifestyle changes, like physical activity and losing weight.

What else can Prehypertension be?

A sudden increase in blood pressure could be caused by different factors. These could be:

• Drug toxicity or overdose, including stimulants like amphetamines and cocaine
• Stroke
• Heart attack
• Withdrawal from calming drugs like benzodiazepines
• Alcohol withdrawal

If high blood pressure is a constant issue, this might be due to secondary health conditions, such as:

• Kidney failure
• Overactive thyroid
• Hyperaldosteronism, a condition that causes your body to produce too much aldosterone hormone
• Cushing’s syndrome, a disorder caused by high levels of cortisol
• Renovascular disease, a condition that affects the blood vessels in your kidneys
• Obstructive sleep apnea
• Pheochromocytoma, a rare tumor of the adrenal gland
• Mineralocorticoid excess syndromes, conditions characterized by high levels of aldosterone

There are also rare genetic disorders that can lead to high blood pressure. These include:

• Liddle syndrome
• Gordon syndrome

What to expect with Prehypertension

Prehypertension or slightly raised blood pressure, and stage 1 hypertension have been linked to increased health risks and mortality in patients. Even after considering other cardiovascular risk factors, having mild increases in blood pressure can lead to a higher risk of strokes, even in those with lower-range prehypertension.

One recent study showed that prehypertensive individuals who managed not to advance to hypertension have a lower risk of cardiovascular disease and death compared to those who do advance to hypertension. This lower risk continues if prehypertension develops early in life, before the age of 55 years.

This highlights the need to identify those with prehypertension or stage 1 hypertension, and to effectively implement strategies to prevent higher-stage hypertension that would require medication. In a related study conducted in China, individuals in a rural area who had prehypertension showed an increased instance of major adverse cardiovascular events, more chances of dying from cardiovascular disease, and higher risk of strokes, when compared to those with normal blood pressure.

Possible Complications When Diagnosed with Prehypertension

If high blood pressure is not treated and kept under control, it can result in a serious condition called hypertension. This can lead to several serious issues related to the heart and blood vessels, such as strokes, heart failure, and even death due to heart-related complications. Other problems that can occur include complications during pregnancy, declining memory and cognitive ability, and damage to organs before symptoms even show, including an enlargement of the left side of the heart and reduced heart function.

Other well-known complications that can come about due to uncontrolled high blood pressure include heart attacks, an enlarged left side of the heart, heart failure, weak and bulging blood vessels in the body (aneurysms), inadequate blood flow to the heart or brain (ischemic strokes), bleeding in the brain (hemorrhagic strokes), long term kidney disease, and eye disease or damage to the retina caused by high blood pressure.

Potential Complications:

• Stroke
• Heart failure
• Cardiovascular mortality
• Pregnancy complications
• Decline in cognition and memory
• Preclinical end-organ damage
• Increased left ventricular mass
• Impaired diastolic function
• Myocardial infarction
• Left ventricular hypertrophy
• Congestive heart failure
• Aneurysms
• Ischemic or hemorrhagic strokes
• Chronic renal failure
• Hypertensive eye disease or retinopathy

Preventing Prehypertension

Doctors typically recommend that everyone, including teenagers and adults, should have their blood pressure checked. However, they’ve found that only using the readings from these office checks isn’t always perfect for diagnosing high blood pressure, particularly a hidden form known as masked hypertension. Research has revealed that blood pressure readings taken outside of the doctor’s office often correlate more accurately with heart-related diseases.

The United States Preventive Services Task Force (USPSTF) suggests that adults aged 18 and over should be screened for high blood pressure during a routine office visit. While this practice can help detect people with consistently high blood pressure readings or individuals with white-coat hypertension (a condition where blood pressure rises because of the stress of being in a medical setting), it’s not foolproof. Office blood pressure checks are good at confirming high blood pressure but not so great at identifying it initially. As a result, many people with masked hypertension remain undiagnosed and are living with a higher risk of heart disease and heart-related death.

The problem is, there’s no cost-effective way to screen for masked hypertension so far.

Checking your blood pressure at home is an option. However, it’s neither practical nor cost-effective to ask everyone to monitor their blood pressure at home. One possible approach could be to focus on providing home blood pressure monitors to those who are at high risk. This group includes individuals who have a significant chance of developing heart disease within the next 10 years or have a strong family history of high blood pressure. Yet, rolling out such monitoring on a large scale, whilst maintaining good detection rates for both high and masked hypertension, is a financial challenge for our healthcare system.