Prehypertension

• What is Prehypertension
• Statistics on Prehypertension
• Risk Factors for Prehypertension
• Progression of Prehypertension
• Symptoms of Prehypertension
• Clinical Examination of Prehypertension
• How is Prehypertension Diagnosed?
• Prognosis of Prehypertension
• How is Prehypertension Treated?
• Prehypertension References

What is Prehypertension

Prehypertension is a relatively new category of blood pressure identified by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7).
It defines a systolic blood pressure of 120 to 139 mm Hg or a diastolic BP of 80 to 89 mm Hg.
Blood pressure (BP) is the force of blood against the walls of arteries. When blood pressure stays elevated over time, it is called high blood pressure, or hypertension.
There are 2 components of blood pressure: systolic and diastolic.
Systolic pressure is the force of blood in the arteries as the heart beats (shown as the top number in a blood pressure reading), whereas diastolic pressure is the force of blood in the arteries as the heart relaxes between beats (shown as the bottom number in a blood pressure reading).

• A normal BP is 120/80 mm Hg.
• Hypertension is defined as a BP of 140/90 mm Hg or higher.
• The gray zone between normal BP and hypertension is now termed prehypertension (120 to 139/80 to 89 mm Hg).

Statistics on Prehypertension

Prehypertension is a common condition. In the United States population aged 20 or greater, an estimated 41.9 million men and 27.8 million women have prehypertension. It is more common in men, and among certain ethnic groups (non-Hispanic White, African American, and Hispanic persons).

Risk Factors for Prehypertension

Just like hypertension, a majority of prehypertension has no known cause. In some patients, a cause may be identified, e.g. kidney diseases, hormonal diseases, hypertension in pregnancy, excessive alcohol intake.

Progression of Prehypertension

Prehypertension may progress to hypertension and lead to heart diseases.
A recent study demonstrated that prehypertension is associated with a higher risk of developing myocardial infarction (heart attack) and coronary artery disease (when the arteries that supply blood to the heart muscle, called coronary arteries, become hardened and narrowed), but it was not shown in the study that there is an increased risk of developing stroke.

How is Prehypertension Diagnosed?

The doctor may perform some blood tests checking for glucose and kidney function. A urine test may also be done to look for blood, glucose and protein. An electrocardiography (ECG) may be performed.

Prognosis of Prehypertension

The prognosis depends on whether the patient develops myocardial infarction, coronary artery disease and stroke. Generally, a person with prehypertension is 3.5 times more likely to have myocardial infarction and 1.7 times more likely to have coronary artery disease compared with someone with a normal BP.
The risk of coronary artery disease with prehypertension is higher among people over 45 years. Men have twice the risk compared with women. In the presence of diabetes mellitus, smoking, obesity and high cholesterol level, the risk of heart diseases increases.

How is Prehypertension Treated?

In people with prehypertension, the recommended treatment is mainly lifestyle and dietary changes. These include moderate restriction on salt in the diet, weight reduction in those who are overweight, regular exercise, avoidance of excessive alcohol intake.
While patients with prehypertension are mainly treated with lifestyle modifications, recent findings that prehypertension does increase the risk of complications e.g. heart diseases raise the question of whether prehypertensive patients should be treated more aggressively with antihypertensive medications. This requires further research in time to come to determine.

Prehypertension References

1. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA 2003; 289: 2560-72.
2. Qureshi AI, Suri FK, Kirmani JF, Divani AA. Prevalence and trends of prehypertension and hypertension in United States: National Health and Nutrition Examination Surveys 1976 to 2000. Med Sci Monit 2005; 11(9): CR403-9.
3. Qureshi AI, Suri MFK, Kirmani JF, Divani AA, Mohammad Y. Is Prehypertension a Risk Factor for Cardiovascular Diseases? Stroke 2005; 36(9): 1859-63.
4. Rose BD. Patient information: Hypertension: What is it, who should be treated, and why [online]. 2003 [cited 2005 September 4th]. Available from URL: http://patients.uptodate.com/topic.asp?file=kidn_dis/5399&title=Hypertension+%28High+blood+pressure%29