New Hypertension Guidelines Lower Starting Point for High Blood Pressure

More than half of the US adult population has high blood pressure, according to updated hypertension guidelines developed by the American Heart Association (AHA) and the American College of Cardiology which were presented at the AHA's 2017 Scientific Sessions on Monday. The guidelines, which are the first comprehensive new high blood pressure guidelines in over a decade, lower the threshold for high blood pressure to 130/80 mm Hg, rather than 140/90 mm Hg.

With the previous definition, 1 in 3 US adults were defined as having high blood pressure (32%). The new guidelines will result in 46% of the US adult population having high blood pressure or hypertension. However, there will only be a small increase in the number of US adults who will require antihypertensive medication, according to the authors. These guidelines are designed to help individuals identify and address the potentially deadly condition much earlier.

In addition to the newly-updated threshold, the guidelines emphasize the importance of using proper technique to measure blood pressure. Blood pressure levels should be based on an average of 2-3 readings on at least 2 different occasions, the authors said.

Paul K. Whelton, MB, MD, MSc, lead author of the guidelines published in the American Heart Association journal, Hypertension and the Journal of the American College of Cardiology, emphasized the importance of accurate measurements of blood pressure, getting the average estimate of blood pressure, and out-of-office measurements to confirm the diagnosis of hypertension and recognize "white coat hypertension" and "masked hypertension".

"White coat hypertension" occurs when pressure is elevated in a medical setting but not in everyday life and “masked hypertension" occurs when pressure is normal in a medical setting but elevated at home, thus necessitating treatment with lifestyle and possibly medications.

The updated guidelines also place an emphasis on lifestyle interventions, recommending the DASH (Dietary Approaches to Stop Hypertension) diet, which includes fruits and vegetables, low-fat or non-fat dairy, whole grains, and less than 1500 mg of daily sodium intake. The guidelines also recommend limiting alcohol to no more than 2 drinks a day for men and no more than 1 a day for women. Exercising for at least 30 minutes, 3 times per week, is another intervention recommendation.

"It's the underlying cause for about 90% of all high blood pressure in our country," Dr. Whelton said.

According to the press release, blood pressure categories in the new guideline are:

• Normal: Less than 120/80 mm Hg;
• Elevated: Top number (systolic) between 120-129 and bottom number (diastolic) less than 80;
• Stage 1: Systolic between 130-139 or diastolic between 80-89;
• Stage 2: Systolic at least 140 or diastolic at least 90 mm Hg;
• Hypertensive crisis: Top number over 180 and/or bottom number over 120, with patients needing prompt changes in medication if there are no other indications of problems, or immediate hospitalization if there are signs of organ damage.

The new guidelines eliminate the category of prehypertension, which was used for blood pressures with a top number (systolic) between 120-139 mm Hg or a bottom number (diastolic) between 80-89 mm Hg. Patients with those readings now will be categorized as having either Elevated (120-129 and less than 80) or Stage I hypertension (130-139 or 80-89).

Previous guidelines classified 140/90 mm Hg as Stage 1 hypertension. This level is classified as Stage 2 hypertension under the new guidelines.

The impact of the new guidelines is expected to be greatest among younger people. The prevalence of high blood pressure is expected to triple among men under age 45, and double among women under 45 according to the report.

Damage to blood vessels begins soon after blood pressure is elevated, said Dr. Whelton. “If you’re only going to focus on events, that ignores the process when it’s beginning. Risk is already going up as you get into your 40s.”

Other changes in the new guideline include:

• Only prescribing medication for Stage I hypertension if a patient has already had a cardiovascular event such as a heart attack or stroke, or is at high risk of heart attack or stroke based on age, the presence of diabetes mellitus, chronic kidney disease or calculation of atherosclerotic risk (using the same risk calculator used in evaluating high cholesterol).
• Recognizing that many people will need 2 or more types of medications to control their blood pressure, and that people may take their pills more consistently if multiple medications are combined into a single pill.
• Identifying socioeconomic status and psychosocial stress as risk factors for high blood pressure that should be considered in a patient’s plan of care.

The new guidelines were developed by the American Heart Association, American College of Cardiology and 9 other health professional organizations. They were written by a panel of 21 scientists and health experts who reviewed more than 900 published studies.

The new guidelines are the successor to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC7), issued in 2003 and overseen by the National Heart, Lung, and Blood Institute (NHLBI). In 2013, the NHLBI asked the AHA and ACC to continue the management of guideline preparation for hypertension and other cardiovascular risk factors.

Reference

High blood pressure redefined for first time in 14 years: 130 is the new high [news release]. Anaheim. AHA's website. http://newsroom.heart.org/news/high-blood-pressure-redefined-for-first-time-in-14-years-130-is-the-new-high. Accessed November 14, 2017.