SAN FRANCISCO, March 28 (Xinhua) -- A study by researchers at Oregon State University (OSU) suggests that elevated blood pressure is not related to high mortality risk among elderly people with weak grip strength.
The findings, based on data from 7,492 Americans age 65 or older who had taken part in the nationally representative Health and Retirement Study, indicate that the relationship between high blood pressure and risk of death is largely dependent on elders' frailty status as measured by walking speed.
"If people are very frail, they typically don't respond well to anti-hypertensive therapy and they are not benefiting from having a low blood pressure," said Chenkai Wu, a graduate student in OSU's College of Public Health and Human Sciences and lead author of the study published in the Journal of the American Geriatrics Society.
"The research is basically saying older adults are not one single group, they're very different in terms of their health status, and drugs may not have the same benefits for everyone. This is consistent with the idea of precision medicine, where you don't just look at age, you look at other things like functional status."
Measured in millimeters of mercury, blood pressure is the force of blood against the vessel walls. Systolic blood pressure, the higher number, is the force during a heartbeat, and diastolic refers to when the heart is at rest. Most people's diastolic blood pressure goes down with age. Systolic blood pressure, though, tends to rise, and high blood pressure, known as hypertension, can put extra strain on the heart and arteries, causing greater risk of heart attack and stroke.
Showing that elevated systolic blood pressure (150 or greater) and diastolic blood pressure (90 or greater) correlated with a substantially higher likelihood of dying for those with normal grip strength, which is 26 kilograms or more for men and 16 kilograms or more for women, the new study suggests that an elderly patient's level of physical functionality should be considered in determining whether anti-hypertensive therapy is warranted.
Six years after being surveyed, 25 percent of the elderly people involved in the study had died.
Grip strength, easily measured by an inexpensive device known as a dynamometer, is a common way to gauge functionality in the elderly. Another often-used measuring stick is walking speed.
"Both measures are markers of functional status, a multidimensional concept. Considering both might be better than considering each measure alone for identifying subgroups of elders for whom high blood pressure is potentially beneficial," Wu was quoted as saying in a news release from OSU.
"We did three analyses. One was to look at gait speed to separate people into two groups, normal and slow. The second part was grip strength -- weak grip and normal grip. Third, we looked at the combinations, and the strongest inverse association between high blood pressure and mortality was for slow walkers with weak grip strength."
The findings suggest that treating high blood pressure in older patients should not follow a one-size-fits-all approach. When an older person is still functioning at a high level physically, high blood pressure indicates mortality risk; however, when the person is not physically robust, high blood pressure is not a marker for mortality risk.