In one of the largest analyses of its kind, researchers found that most middle-aged and older individuals with high blood pressure have a form of the disease in which their systolic pressure -- the top number in a blood pressure reading -- is too high.
This finding is reported in an article in the March issue of Hypertension: Journal of the American Heart Association.
"The higher the systolic pressure, the greater the risk of death and disability from heart disease and stroke," says Nathan D. Wong, Ph.D., a cardiovascular epidemiologist and director of the Heart Disease Prevention Program, University of California, Irvine.
High blood pressure is defined as systolic pressure of 140 mmHg or higher (top number) and/or diastolic pressure (bottom number) of 90 mmHg or higher for most people. Isolated systolic hypertension is when the top reading is greater than or equal to 140 mm Hg and the bottom number is less than 90 mm Hg.
This analysis finds that the form of high blood pressure called isolated systolic hypertension is the dominant form of uncontrolled high blood pressure in people over age 50, occurring in more than 80 percent of individuals in this age group who have high blood pressure.
Among a "middle-aged" group -- people 50 to 59 years old -- 87 percent had isolated systolic hypertension. This percentage increases in those older than age 60. People younger than 50 tended to have elevated diastolic pressure as the most common type of uncontrolled high blood pressure.
"Primary focus on treating diastolic high blood pressure and possibly physician fears of lowering of diastolic blood pressure too far may contribute to poor systolic blood pressure control," the authors report.
Physicians need to become aware of the importance of untreated and inadequately treated isolated systolic pressure in middle-aged and older people, say the researchers.
"There needs to be more aggressive attempts to control systolic pressure in middle-aged and older people, including multiple drug therapy if single-drug therapy and lifestyle changes are not adequate," says Wong.
The National Health and Nutrition Examination Survey, (NHANES) III is a national survey of 19,661 adults conducted from 1988-1994 designed to provide estimates of common chronic health conditions and their associated risk factors.
For the hypertension component, blood pressures were measured to provide estimates of prevalence, awareness, treatment, and control of hypertension. The investigators examined patterns of systolic and diastolic hypertension by age among individuals in the NHANES III database in order to determine when treatment and control efforts for high blood pressure should be recommended.
The survey indicates a poor level of awareness, treatment and control of high blood pressure in all age groups. About 48 percent of individuals with high blood pressure are not being treated for the condition, while 29 percent are inadequately treated.
The current study shows that of those who received either no treatment or inadequate treatment, 65 percent had systolic hypertension; 21 percent had systolic/diastolic hypertension (meaning both numbers were high); and 14 percent had diastolic hypertension.
Individuals with hypertension were broken down into two age groups: those older than age 50, and those younger than 50. Three fourths of those with any type of hypertension were older than 50.
Wong notes that many physicians are satisfied when the minimum goal of 140 systolic and 90 diastolic is reached. However, the minimum goal is not the optimal goal.
"The optimal goal is systolic pressure below 120 and diastolic below 80," Wong declares.
Individuals older than age 50 who are not receiving treatment -- or who receive inadequate treatment -- for isolated systolic hypertension require a two-fold greater reduction in systolic pressure to reach optimal levels, says Wong.
The study was led by Stanley S. Franklin, M.D and other co-authors are Milagros J. Jacobs, M.S.; Gilbert J. L'Italien, Ph.D; and Pablo Lapuerta, M.D.
[Contact: Carole Bullock]