High Blood Pressure – Part I: Its Prevalence, Definition, Measurement and Classifications

Suggested Citation: Garko, M. G. (2014, May). High blood pressure – Part I: Its prevalence, definition, measurement and classifications. Health and Wellness Monthly. Retrieved (insert month, day, year), from www.letstalknutrition.com.

High Blood Pressure – Part I: Its Prevalence, Definition, Measurement and Classifications

Michael Garko, Ph.D.

Syndicated Host & Producer of Let’s Talk Nutrition

Introduction

High blood pressure (HBP), clinically termed “hypertension,” is a major, independent risk factor for cardiovascular diseases (CVD) and stroke. Specifically, HBP increases the risk for heart attack, stroke, congestive heart failure (CHF) and coronary heart disease (CHD) (see Go, et. al, 2014). According to the American Heart Association’s  2014 update on heart disease and stroke, “[a]pproximately 69% of people who have a first heart attack, 77% of those who have a first stroke, and 74% of those who have CHF have BP >140/90 mm Hg” (Go, et. al, 2014, p. e109) or otherwise HBP.

In addition to increasing a person’s risk for CVD and stroke, HBP is responsible for nearly 20% of all deaths in the United States. Further, those suffering from HBP typically experience a shorter overall life expectancy, a shorter life expectancy that is CVD-free and more years having to live with CVD (see Go, et. al, 2014).

Clearly, HBP is a serious health condition. It is called the “silent killer” for good reason. It develops most often out of awareness and without any advanced warning. Also disturbing is that, according to the American Heart Association (2009), the cause of 90-95% of HBP cases is not known. Making matters worse, it is predicted that by 2030, approximately 41.4% of adults in America will suffer from hypertension, representing an increase of 8.4% from estimates in 2012 (Go, et. al, 2014).

Given its increased risk for CVD, stroke and death, its current and projected prevalence, its association with a shorter overall life expectancy and life expectancy free from CVD, along with its association with living more years suffering from CVD, the May, 2014, issue of Health and Wellness Monthly focuses on HBP. Special attention will be devoted to the prevalence, definition, measurement and classification of HBP. This article is the first in a series on HBP.

Prevalence of High Blood Pressure

In terms of its prevalence, the American Heart Association’s most recent statistical snapshot of HBP in the United States reveals that it affects about one-in-three adults, with approximately six percent of American adults suffering from undiagnosed HBP. The estimated prevalence for HBP in the United States is 77.9 million for adults 20 years of age and older. Of those with HBP, 81.5% know of their condition; 74.9% are under treatment; 52.5% have their HBP under control and 47.5% do not (see Go, et. al, 2014).

Prevalence and Gender

When it comes to gender, HBP is an equal opportunity health offender. Men and women suffering from HBP is 37.6% and 40.1%, respectively. Age tends to interact with gender and the prevalence of HBP among men and women. That is, there is a higher percentage of men than women who suffer from HBP up until age 45 and then from 45-54 but from 55-64 years of age the percentages associated with men and women are pretty much the same. Beyond 64 years of age, there are more women than men with HBP (see Go, et. al, 2014).

Blood Pressure – Definition and Measurement

Blood pressure is the measurement of the force of the circulating blood as it pushes against the walls of the arteries each time the heart contracts and pumps blood throughout the body’s vast arterial system. Blood pressure involves and is determined by how much blood the heart pumps in conjunction with how much resistance there is to the blood flow in the arteries. The more blood the heart pumps and the narrower the arteries, the higher the blood pressure (see Mayo Clinic, 2014).

Blood pressure measurements include systolic and diastolic pressure readings represented in millimeters of mercury (mm Hg). The systolic pressure number represents the highest force against the walls of the arteries upon contraction of the heart, while the diastolic pressure represents the lowest pressure against the walls of the arteries between contractions when the heart is at rest. A blood pressure cuff is used to measure blood pressure (see National Heart, Lung, and Blood Institute, 2012).

High Blood Pressure – Definition, Categories and Guidelines

HBP is not a disease per se but rather a serious medical condition which becomes implicated with disease in that it can cause disease and disease-related complications and be caused by pre-existing, disease-related conditions associated with the kidneys, adrenal glands, thyroid gland and cardiovascular system (i.e., heart and arteries). This is one of things which makes HBP so dangerous, which will be discussed in an upcoming issue of Health and Wellness Monthly.

The National Heart Lung and Blood Institute (NHLBI) (2012) provide blood pressure guidelines for normal, prehypertensive and high blood pressure. According to the NHLBI (2012), if blood pressure readings are above normal (i.e., greater than 120/80 mmHg) most of the time, then this would indicate being at risk for HBP. The following table of blood pressure categories is from the NHLBI (2012):

Categories for Blood Pressure Levels in Adults (measured in millimeters of mercury, or mmHg)

Category Systolic
(top number)
Diastolic
(bottom number)
Normal Less than 120 And Less than 80
Prehypertension 120–139 Or 80–89
High blood pressure
     Stage 1 140–159 Or 90–99
     Stage 2 160 or higher Or 100 or higher

(National Heart Lung and Blood Institute, 2012, p.1)

Blood Pressure Classifications

Those suffering from HBP represent a diverse group of people, resulting in four literature-referenced classifications (see Acelajado & Calhoun, 2010). Typically, HBP is classified as either primary/essential or secondary hypertension. However, there are also the classifications of resistant hypertension and hypertensive crisis.

Primary Hypertension

Primary (sometimes referred to as essential) hypertension, or simply HBP, identifies those instances where there is no apparent or clear cause and its occurrence is associated with genetics, an unhealthy diet (e.g., excess sodium, excess saturated fat, inadequate intake of fruits and vegetables, excess alcohol, etc.), sedentary lifestyle and obesity. It is the most common type of hypertension. Approximately, 90%-95% of HBP cases are clinically categorized as primary hypertension. Primary hypertension can be caused by an interaction between genetic and environmental (i.e., everything other than genetic-related) factors. Currently, there is no recognized cure for primary hypertension.

Secondary Hypertension

Secondary hypertension is HBP caused by a pre-existing medical condition involving the kidneys, adrenal glands, thyroid gland, cardiovascular system, endocrine system or modifiable and non-modifiable risk factors such as age, race, family history, diabetes, sleep apnea, sedentary lifestyle, excess stress, alcohol and tobacco use, excess sodium, potassium deficiency, obesity, pregnancy and medications (see American Heart Association, 2012; Mayo Clinic, 2014; Rafey, 2013).

Resistant Hypertension

Resistant hypertension is defined as blood pressure that remains above blood pressure goal despite the concurrent use of three antihypertensive agents of different classes (Calhoun et. al, 2008). “As defined, resistant hypertension includes patients whose blood pressure is controlled with use of more than 3 medications. That is, patients whose blood pressure is controlled but require 4 or more medications to do so should be considered resistant to treatment” (Calhoun et. al, 2008, p. 1440). Patients who suffer from resistant hypertension and whose blood pressure remains uncontrolled even though they are using three or more antihypertensive drugs are at an increased cardiovascular risk compared with those who are part of the general hypertensive population (Acelajado & Calhoun, 2010).

Hypertensive Crisis

As its name would imply, an hypertensive crisis involves an acute, severe surge in blood pressure. It is sometimes referred to in the literature and clinical practice as hypertensive emergency. So what is it exactly that makes an episode of an acute severe rise in blood pressure a crisis or emergency? According to Varon & Marik (2003), “most authorities have defined hypertensive crises or emergencies as a sudden increase in systolic and diastolic blood pressures associated with ‘acute end-organ damage’ (i.e. cardiovascular, renal, central nervous system) that requires immediate management” (p. 374). Varon & Marik (2003) make a distinction between hypertensive emergency and hypertensive urgency. For them, the thing that distinguishes the former from the latter is not a surge in the absolute level of blood pressure but rather it is the organ damage which makes it a crisis for the patient and doctor treating the patient (see Varon & Marik, 2003).

Conclusion

Given that one third of the population suffers from it, along with its increased risk for CVD, stroke and death, its current and projected prevalence, its association with a shorter overall life expectancy, a shorter life expectancy free from CVD and living more years suffering from CVD, it is no wonder that HBP stands among the most dangerous health issues facing Americans in the 21st century. In fact, it is among the most entrenched health conditions in our country. Future projections of its growth, an aging population and an ever emerging unhealthy diet and lifestyle putting people at risk for HBP serve to strongly suggest that it will continue to prevail in its prevalence.

Upcoming issues will consider how dangerous HBP is to a person’s health, risk factors associated with it, recognized approaches to prevent and treat it and how, as a serious medical condition, HBP is implicated as both a cause and consequence of disease. The purpose of the HBP series is to help educate and persuade health consumers about how serious a medical condition HBP actually is and how it can single handedly undermine a person’s effort to live a long life with quality of life or otherwise age successfully across the lifespan.

References

Acelajado, M.C. & Calhoun, D.A. (2010, November). Resistant hypertension, secondary hypertension, and hypertensive crises: Diagnostic evaluation and treatment. Cardiology Clinics, 28 (4): 639-654.

American Heart Association (2012). Understand your risk for high blood pressure. Retrieved April 22, 2014, from http://www.heart.org/

Calhoun, D.A., Jones, D, Textor, S., Goff, D.C., Murphy, T.P., Toto, R. D., White, A., PhD; Cushman, W.C., White, W.,  Sica, D., Ferdinand, K., Giles, T.D., Falkner, B. & Carey, R.M. (2008). Resistant hypertension: diagnosis, evaluation, and treatment: A scientific statement from the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research, Hypertension, 117, 25: e510–e526,

Go, A.S., Mozaffarian, D., Roger,V.L., Benjamin,E.J., Berry, J.D., Blaha, M. J., Dai, S., Ford, E.S., Fox, C.S., Franco, S., Fullerton, H.J., Gillespie, C., Hailpern, S.M., Heit, J.A., Howard, V.J., Huffman, M.D., Judd, S.E., Kissela, B.M., Kittner, S.J., Lackland, D.T., Lichtman, J.H.,. Lisabeth, L.D., Mackey, R.H., Magid, D.J., Marcus, G.M., Marelli, A., Matchar, D.B., McGuire, D.K., Mohler, E.R., Moy, C.S., Mussolino, M.E., Neumar, R.W., Nichol, G., Pandey, D.K., Paynter, N.P., Reeves, M.J., Paul D. Sorlie, P.D., Stein, J., Towfighi, A., Turan, T.N., Virani, S.S., Wong, N.D., Woo, D. & Turner, M.B.  (2014). Association heart disease and stroke statistics–2014 update: A report from the american heart association. Circulation, 129: e28-e292.

Mayo Clinic, (2014). High blood pressure (hypertension). Retrieved April 22, 2014 from http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/basics/definition/con-20019580

National Heart Lung and Blood Institute (2012). What is high blood pressure. Retrieved April 22, 2014 from http://www.nhlbi.nih.gov/health/health-topics/topics/hbp/.

Rafey, M. (2013). Hypertension. Retrieved April 22, 2014 from http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/nephrology/arterial-hypertension/.

Varon, J. & Marik, P.E. (2003). Clinical review: The management of hypertensive crises. Critical  Care, 7(5): 374–384.

Suggested Citation: Garko, M. G. (2014, May). High blood pressure – Part I: Its prevalence, definition, measurement and classifications. Health and Wellness Monthly. Retrieved (insert month, day, year), from www.letstalknutrition.com.