Even Slightly High Blood Pressure Poses Health RiskOctober 31, 2001
NEW YORK (Reuters Health) - People with blood pressure levels that tend to be slightly elevated but still considered to be within normal ranges--called high-normal--are at increased risk for suffering from heart disease, according to a new study.
"Our findings emphasize the need to determine whether lowering high-normal blood pressure can reduce the risk of cardiovascular disease," writes lead author Dr. Ramachandran S. Vasan of the Boston University School of Medicine.
The findings, published in the November 1st issue of the New England Journal of Medicine, could have important implications for how aggressive doctors are in giving medications to patients whom they previously simply observed.
In the study, the team of researchers monitored blood pressure levels of 6,859 men and women. They then compared heart disease related illness in people with high-normal blood pressure to people with high blood pressure.
Blood pressure readings are taken in two numbers. The systolic value (the first number in a blood pressure measurement) describes the pressure in the heart during contraction. The second number, the diastolic value, represents the pressure when the heart is at rest between beats.
Blood pressure readings of less than 140 over 90 are considered normal, while higher values have long been considered elevated and a risk for heart disease. A systolic pressure of 130 to 139 or a diastolic pressure of 85 to 89 is considered to be high-normal, but the significance of these values was unclear.
After following the patients for 10 years the researchers found that 4% of the women and 8% of the men with high-normal blood pressure who were between the ages of 35 and 65 had some kind of heart disease. Patients between the ages of 65 and 90 with high-normal blood pressure had a much higher risk for heart disease--18% of the women and 25% of the men, the study indicates.
Overall, women with high-normal blood pressure had a 2.5 times greater risk of heart disease than did those with normal blood pressure, and men with high-normal values had 1.6 times greater risk of heart disease than did men with normal values.
"Although our results demonstrate that high-normal blood pressure is a marker of an elevated risk for (heart) disease, it is uncertain whether the increased risk is attributable solely to subjects' blood pressure levels," the authors write.
"These findings lend further credence to the theory that high-normal blood pressure must be categorized differently from normal or optimal blood pressure," writes Julio a Panza of the Washington Hospital Center, in Washington DC in an accompanying editorial.
The finding in the current study "that high normal blood pressure is more akin to high blood pressure than it is to normal pressure is an important advance in our understanding of the magnitude of the problem," he concludes.
SOURCE: The New England Journal of Medicine 2001;345:1291-1297