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Primary hypertension
1. How is hypertension defined and classified?
The Eighth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (Joint National Committee 8), published in 2014, continues to classify hypertension by the degree of blood pressure (BP) elevation ( Table 62.1A and B ). The measurement must be based on the average of at least two seated measurements on each of two or more office visits. For children, hypertension is defined as systolic or diastolic BP greater than the 95th percentile of BP for a given age, height, and gender, on repeat measurement.
Table 62.1A.
Classification for Adults 18 Years or Older with Elevated Blood Pressure
| BP Category | SBP | DBP | |
|---|---|---|---|
| Normal | <120 mm Hg | and | <80 mm Hg |
| Elevated | 120–129 mm Hg | and | <80 mm Hg |
| Hypertension | |||
| Stage 1 | 130–139 mm Hg | or | 80–89 mm Hg |
| Stage 2 | 140–159 mm Hg | or | 90–99 mm Hg |
| Stage 3 | ≥160 mm Hg | or | ≥100 mm Hg |
BP, Blood pressure; DBP, diastolic blood pressure; SBP, systolic blood pressure.
Table 62.1B.
Classification for Adults 18 Years or Older with Elevated Blood Pressure
| Hypertension Stage | SBP | DBP |
|---|---|---|
| Prehypertension | 120–139 mm Hg | Or 80–89 mm Hg |
| Stage I | 140–159 mm Hg | Or 90–99 mm Hg |
| Stage II | ≥160 mm Hg | Or ≥100 mm Hg |
DBP , Diastolic blood pressure; SBP , systolic blood pressure.
While national and international guidelines have largely promoted uniform BP targets for all populations (<140/90 for those younger than 80, <150/90 for those older than 80), there is increasing recognition that “goal” BP is patient and comorbid specific. For those with prior strokes, the range of 125 to 135/70 to 80 is desired, whereas 130 to 135/80 is adequate for those with non-proteinuric kidney disease. Finally, among those at low-to-moderate risk for cardiovascular disease without diabetes, 120 to 125/70 to 80 appears to provide maximal benefit. The 2017 ACC/AHA guidelines define the systolic BP target of <130/80 mm Hg for everyone except those with a <10% 10-year risk for cardiovascular (CV) events where it is still <140/90.
2. What is the appropriate means of measuring BP?
Measuring BP in the office should be performed with individuals seated for at least 5 minutes in a chair with their feet on the ground and an arm supported at the level of the heart. An appropriate-sized cuff with the cuff bladder encircling at least 80% but no more than 100% of the upper arm should be used; attention should be paid to ensure the bladder covers the brachial artery. While the “gold standard” remains a mercury sphygmomanometer, electronic (oscillometric) monitors have grown in popularity, and are being utilized in both clinical trials and office-based practice. Ausculatory oscillometric blood pressure (AOBP) devices were used in trials such as SPRINT and ACCORD, but they provide readings that are 5 to 10 mm Hg systolic lower than conventional office measurements. Electronic units are simpler to use and can be set on a timer, which allows the provider to leave the room (thereby reducing the white coat effect). Moreover, they do not have the environmental concerns of mercury-based devices. However, many offices do not have a separate quiet room nor the time to measure BP in this way.
3. Is home blood pressure monitoring useful?
Home BP monitoring, or ambulatory BP monitoring, is better at predicting cardiovascular events compared to office-based readings. Home BP is documented to improved BP control and patient adherence with medications. It has also been validated against daytime 24-hour ABPM. Therefore home BP should occupy a prominent role in the management of hypertension.
ABPM is used to rule out both white-coat and masked hypertension; BP readings during periods of dizziness or orthostasis can also aid in assessing the contribution of BP to such symptoms.
Wrist-based cuff devices are unreliable, and therefore upper arm (brachial) cuff units are preferred. While many units are available, validation and accuracy are not prerequisites for production; therefore only rigorously tested machines should be purchased. The appropriate technique is like that for ausculatory measurements. Machines should be rechecked annually by measuring pressures against a validated unit.
4. What is the prevalence of hypertension in the united states? How well is hypertension controlled among those with a diagnosis of hypertension?
The prevalence of hypertension rises with age so those at age 80 have a 90% chance of being hypertensive. According to the most recent (2014) National Health and Nutrition Examination Survey (NHANES) data, nearly one-third of Americans over the age of 18 suffer from hypertension, with the disease affecting two-thirds of those above age 60. The rates among men and women are similar. Hypertension is more common among African Americans (42%) than among Caucasians, Hispanics, and those of Asian ancestry (25% to 28%).
Awareness, treatment, and control of hypertension continue to rise but remain suboptimal. As at 2012, awareness rates were at 80%, treatment at 75%, and control rates at 53%.
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