New hypertension guidelines released Monday at Scientific Sessions implicate how blood pressure is classified and measured and how hypertension is diagnosed and managed.
According to the new guidelines:
Normal blood pressure is less than 120 mm Hg systolic and less than 80 diastolic.
Elevated blood pressure is 120-129 systolic and less than 80 diastolic.
A new category — Stage 1 hypertension — is 130-139 mm Hg systolic or 80-89 mmHg diastolic. Under prior guidelines, these individuals were classified as having prehypertension. Adults 65 and older fall under this same definition.
“The reason to call it Stage 1 hypertension is clear evidence of substantial elevation in risk compared to normal pressure, just about a two-fold increase in the risk of heart attack, for example,” said Paul K. Whelton, MD, MSc, who chaired the 21-member multidisciplinary guideline writing committee.
The new definition will increase the prevalence of hypertension by about 14 percent in the United States and significantly more in some patient subgroups based on age, gender and ethnicity. But the number of patients needing pharmacologic therapy will rise a modest 1.9 percent, or about 4.2 million adults, said Whelton, clinical professor and the Show Chwan Health System Endowed Chair in Global Public Health at the Tulane University School of Public Health and Tropical Medicine in New Orleans, Louisiana.
“Although we identify more people to be treated, we are more focused on who should get treated with drug therapy,” Whelton said. “It’s really those people with stage 1 hypertension who are at high risk who should be getting pharmacologic treatment as well as nonpharmacologic interventions. That’s about 30 percent of individuals with systolic blood pressure between 130 mm Hg and 139 mm Hg.”
Most people with stage 1 hypertension and elevated blood pressure should make these nonpharmacologic lifestyle changes: no tobacco use; weight loss; a DASH-type diet rich in fruits, vegetables, whole grains and low-fat dairy products; reduced sodium intake; increased potassium intake, preferably through dietary changes such as adding bananas, dark green leafy vegetables and other foods high in potassium; increased physical activity; and moderate or no alcohol consumption.
The lifestyle changes can reduce systolic blood pressure 4 mm Hg to 11 mm Hg, according to the guidelines. Diet and exercise have the greatest impact on blood pressure, Whelton said.
People with stage 1 hypertension should also be assessed for cardiovascular risk, according to the guidelines. Those at high risk should receive pharmacotherapy as well as nonpharmacologic interventions. Most can be treated with a thiazide diuretic, ACE inhibitor, angiotensin receptor blocker or calcium channel blocker. The guidelines note that once-daily medication may improve adherence compared to multiple medications each day.
People with a prior stroke, myocardial infarction, other major events, diabetes or chronic kidney disease are at high risk under the new guidelines.
Those who do not meet these automatic inclusion criteria should have their risk assessed, according to the guidelines. The AHA recommends using the Heart Risk Calculator at www.cvriskcalculator.com. People who have a 10 percent or greater risk of a major cardiovascular event in the next 10 years are considered high risk and should receive drug treatment.
Individuals with systolic blood pressure of 140 mm Hg or higher or diastolic of 90 mm Hg or higher have stage 2 hypertension and need lifestyle changes plus drug treatment with two or more agents from different classes.
A second major innovation in the guidelines is the focus on accurate blood pressure measurement in the office and at home. In-office blood pressure testing has long been the standard of care, but not all providers measure blood pressure appropriately or accurately, Whelton said. The guidelines include specific recommendations for blood pressure measurement, such as requiring patients to rest before measuring, taking multiple measurements in both arms and averaging readings to help reduce random error.
For the first time, the new guidelines emphasize the need for regular at-home blood pressure measurement to supplement in-office measurements.
“There’s an increasing body of literature that what happens in the office is not always what happens outside the office,” Whelton said. “One group has high blood pressure measured in the office but normal pressures outside the office. These white-coat hypertensives have a risk pattern that is more like nonhypertensives.”
The more insidious problem is masked hypertension, which is when blood pressure readings in the office are normal, but elevated outside the office. People with masked hypertension have a risk pattern similar to those with sustained hypertension, Whelton said. Both groups will be missed if clinicians rely only on in-office blood pressure measurements.