Dear Dr. K,
What is the right blood pressure for a woman in her 80s who has kidney problems? My aunt's doctor recently sent her to a kidney specialist, because her kidney function is low and her blood pressure is too high. But the kidney doctor says her blood pressure is fine, and that it shouldn't be below 140 at her age, because the arteries are inelastic. Is it true that a pressure of 140 is okay? My aunt's regular doctor has always told us to aim for less than 130.
Most geriatricians would side with the kidney specialist on this one. Although high blood pressure is a major health problem for Americans overall, as people get older, it gets more and more likely to develop side effects from blood pressure medicine. So making sure that people aren't on too much blood pressure medication is common practice in geriatrics, especially if there's been any concern about falls.
As people age, they're more likely to develop a drop in blood pressure when they stand up. Why? Well, standing causes one's blood to temporarily pool in the legs. In younger, healthier people, the body almost instantly tightens blood vessels and makes other adjustments, so that the brain doesn't experience much drop in blood supply. But like everything else in the body, this system tends to wear down and get slower with age. So in an older person, it can take longer for the blood vessels to adjust to a standing position. During this time, reduced blood flow to the brain can cause dizziness, weakness, vision changes, or even passing out.
Studies have found that about 20 percent of adults 65 and older experience these changes in blood pressure (technically called "postural" or "orthostatic" changes), although many people don't actually notice any dizziness or other symptoms. And most blood pressure medications increase the chance of having these postural changes. If you're a fit 67-year old, you'll probably barely notice a temporary drop in blood pressure. But if you're in your 80s, such a drop could easily become the straw that breaks the camel's back and contributes to a disastrous fall.
So what blood pressure should older adults aim for? That's actually a topic of considerable debate among experts. The gospel I learned in medical school was that lower blood pressure is almost always better. And indeed, studies have shown that even in the "very elderly" (age 80 or older), treating high blood pressure to get it below 150/80 does really reduce the risk of stroke and death. But it's been much harder for researchers to prove that there's a real benefit to getting blood pressure below 140/80. So there's a slight "gray zone" of acceptability for the very old.
For all these reasons, I usually don't use medication to get an older person's blood pressure under 140/80, unless he or she has other medical symptoms that will improve with lower blood pressure. Incidentally, kidney disease is one of those medical problems for which I'd consider a lower blood pressure goal, depending on the specifics of the situation. (Heart failure is another common condition for which I consider aiming for lower blood pressure.) However, I'd also trust a kidney doctor to tell me when a lower blood pressure goal isn't necessary. So I say go with the specialist's advice.
My prescription for caregivers
"¢ If your loved one is on medications for blood pressure, make sure you know what the doctor's goal is. You'll want to let the doctor know if your loved one is often either way above, or way below, goal blood pressure. "¢ Know that postural (also known as orthostatic) changes in blood pressure become more and more common as people age. If there's any concern about dizziness or falls, have your loved one checked for postural blood pressure changes. "¢ Postural changes in blood pressure are a relatively common side effect of blood pressure medications. Often it's possible to adjust medications, to reduce these blood pressure drops. This can decrease symptoms such as dizziness and, sometimes, falls. "¢ Although it's important to treat high blood pressure no matter how old a person is, the goal blood pressure to aim for remains controversial. If your loved one is age 80+, or otherwise seems frail, ask the doctor to clarify the expected benefits if the goal blood pressure is less than 140/80.