The study found that almost three fourths of those 80 years and older have hypertension -- blood pressure greater than 140 systolic over greater than 90 diastolic. Fewer than 10 percent have "normal" blood pressure levels -- less than 120 systolic over less than 80 diastolic.
The research, which was based on data from the National Heart, Blood, and Lung Institute's long-standing Framingham Heart Study, also found that older hypertensive women are especially at risk for having poorly controlled hypertension.
Risks for cardiovascular disease also are substantial in this population, indicating the need for greater efforts at safe, effective risk reduction among the oldest hypertensive persons. Among men and women study participants with the highest levels of blood pressure at age 80 or older, 25 percent had a major cardiovascular event (heart attack, stroke or hospitalization for heart failure) within six years' follow-up.
"Greater public health and clinical efforts are needed for patients and physicians to improve awareness of the risks of hypertension, to understand the benefits and potential risks of treatment and to identify safe and effective strategies for blood pressure and overall cardiovascular disease risk reduction in the oldest hypertensive individuals," said Donald Lloyd-Jones, M.D., assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine, who was lead author on the article.
The very elderly are among the fastest growing segments of the U.S. population and they have the highest prevalence of hypertension. It is rare to escape the development of hypertension with aging: Even for individuals free of hypertension at age 65, the remaining lifetime risk of developing hypertension is approximately 90 percent, Lloyd-Jones said.
Despite numerous clinical studies showing the benefits of lowering blood pressure in older hypertensive persons, data suggest that rates of treatment and control are less than optimal and that risks for cardiovascular disease are substantial, Lloyd-Jones said. Studies from national surveillance data, however, are typically limited to adults younger than age 75, and information regarding current patterns of treatment and control of high blood pressure among those 80 and older is sparse.
Lloyd-Jones and co-researchers Jane C. Evans and Daniel Levy, M.D., from the National Heart, Lung, and Blood Institute analyzed data from almost 5,300 Framingham Study participants (2,300 men and approximately 3,000 women).
Among the oldest hypertensive individuals, only 38 percent of men and 23 percent of women had their blood pressure controlled to recommended levels of less than 140 systolic over less than 90 diastolic.
It appeared that poor control was due in part to lack of use of combination drug therapy and, perhaps, to poor selection of drug classes. Despite abundant evidence suggesting that thiazide diuretics are the most cost-effective drugs for blood pressure reduction, and that they are especially effective in the elderly, the researchers found overall low rates of thiazide use, particularly among men.
Among the oldest hypertensive persons receiving blood pressure-lowering medication, 62 percent were receiving only one antihypertensive medication, and only 23 percent of men and 38 percent of women were receiving a thiazide diuretic.
The researchers observed high prevalence of use of more expensive drugs, such as ACE inhibitors and other drugs, such as alpha-blockers, although data supporting their effectiveness in older hypertensive are limited.
Control of blood pressure is more difficult to achieve when starting at a higher baseline blood pressure, as is often the case with older hypertensive individuals, Lloyd-Jones said.
In addition, clinicians may be reluctant to treat older patients as aggressively, because of perceived lower benefits or possible increased risk of side effects.
"In light of these findings, and the results from clinical trials, the very elderly may have the most to gain from hypertension treatment. We must make identification, treatment and, when possible, control of hypertension in this age group a national priority," Lloyd-Jones said.
Lloyd-Jones is supported by grant K23 HL04253 from the National Heart, Lung and Blood Institute. The Framingham Heart Study is supported by NIH/NHLBI contract N01-HC-25195.
Journal
JAMA