People with prehypertension are also at risk of death from stroke and heart disease.
According to the U.S. National Heart, Lung and Blood Institute, a healthy blood pressure reading is 120/80 mm Hg or less. However, researchers say that even those whose blood pressure readings fall into the bracket of prehypertension – i.e. 120-139/80-89 mm Hg, are at risk of death from stroke and heart disease.
Studies of prehypertension and mortality are controversial after adjusting for other cardiovascular risk factors. This led a group of researchers to try to evaluate the association of prehypertension with all-cause and cardiovascular disease (CVD) mortality.
For the study, which was published in the recent edition of the American Heart Journal, they searched PubMed, EMBASE, Cochrane Library databases, and conference proceedings for studies with data on prehypertension and mortality. The studies were conducted in the U.S., Europe, Australia and several Asian countries. Eventually, they derived data of 1,129,098 participants from 20 prospective cohort studies that matched their research criteria.
They also conducted subgroup analyses according to blood pressure, age, gender, ethnicity, follow-up duration, participant number, and study characteristics. They calculated that no less than 15 percent of deaths from stroke and 11 percent of heart disease deaths would be avoided by eliminating hypertension that is above the ideal, but below the formal definition of “high.” In fact, the very category of prehypertension was created as a result of studies linking readings below 140/90 mm Hg to increased risk of cardiovascular problems in the first place.
Overall, the study found that blood pressure readings in the prehypertension range were not linked to any increased risk of death from all causes. Prehypertension-level readings were, however, tied to a 28 percent increased risk of death from cardiovascular disease and a 41 percent higher risk of stroke death, compared to people in the same studies with normal blood pressure.
Most of the raised risk was seen among people at the high end of the prehypertension range, with readings between 130-139/85-89. The researchers suggest that doctors consider this when deciding how to treat slightly elevated blood pressure. The study also confirmed previous research that has found higher risk of cardiovascular disease deaths among U.S. blacks.
U.S. guidelines for treating high blood pressure were recently updated by a joint national committee, which suggested that doctors prescribe drugs to adults aged 60 years and older when systolic pressure is above 150 mm Hg. For those younger than 60, the committee recommended medication at levels 140 mm Hg and higher.
The study group advice people with blood pressure in the prehypertensive range, to have periodic health screenings, stop smoking, increase their physical activity and maintain a healthy body weight. They also recommend that medical professionals pay more attention to patients with borderline hypertension.