Blood Pressure, Heartbeat Problems Aggravate Alzheimer's
TUESDAY Nov. 6, 2007 -- Alzheimer's disease may progress faster in patients with high blood pressure or a type of irregular heartbeat called atrial fibrillation, a new study found.
"The main point of these findings is that vascular factors do affect the rate of progression in Alzheimer's, so treatment of these factors could reduce the rate of decline," said study author Dr. Michelle Mielke, an assistant professor of psychiatry at Johns Hopkins University School of Medicine.
"There are some dementia medications out there that are effective for some people [with Alzheimer's] but, for some people, they aren't effective or can't be tolerated," added Mielke. "Perhaps this is another way of reducing [their] decline. Even if you can give people a few more months with a better quality of life and keep them more cognizant than in the past, I think that then it is worth it."
The study is published in the Nov. 6 issue of Neurology.
An estimated 4.5 million Americans have Alzheimer's disease, according to the National Institute on Aging, but that number is expected to increase dramatically as the population grows older. Experts believe that about half of people 85 and older may have the disease.
Mielke and her colleagues studied a group of 135 women and men 65 and older from Cache County, Utah. The study participants had developed dementia that was characterized as "possible or probable AD" [Alzheimer's disease] without concurrent vascular dementia, the study said.
Those patients at the time of diagnosis who had systolic blood pressure greater than 160 or atrial fibrillation deteriorated more rapidly, based on standard tests of functioning and mental status, than those who didn't have the conditions, the study found.
Age also played a role in the progression of Alzheimer's for patients who had certain vascular conditions, the study said. The disease progressed more rapidly in older participants with high blood pressure, angina or a history of a heart attack, the study authors said.
But the researchers also found some unexpected results -- a history of diabetes or heart bypass at the time of diagnosis was associated with slower progression of Alzheimer's, the study said.
Mielke said the researchers aren't sure what the association between diabetes and slower Alzheimer's progression means. They speculated that patients who'd undergone heart bypass surgery may have benefited from their heart's increased ability to pump oxygen-rich blood to the brain. Other factors that may have helped bypass patients include better overall health, better diets, and closer monitoring by physicians, she added.
The study did not specifically look at the impact of treating vascular conditions such as high blood pressure on Alzheimer's patients. But the results did show that patients who had been treated with high blood pressure drugs prior to their Alzheimer's diagnosis did decline more slowly, according to one rating scale, the researchers said.
Earlier this year, French researchers reported that Alzheimer's patients with vascular disease who received standard medications -- such as statins, anti-clotting agents, insulin and anti-hypertensive drugs -- did better cognitively over a 36-month period than those who didn't receive such treatment.
Dr. Lon Schneider, a professor of psychiatry and behavioral science at the University of Southern California Keck School of Medicine, said the work of Mielke and her colleagues is "confirming and affirming that vascular factors have a significant role to play in Alzheimer's disease in moderating the onset and the course of the illness. It suggests a large portion of treatment and preventive treatment should be focused on cardiovascular disease."
Dr. William Thies, vice president for medical and scientific relations for the Alzheimer's Association, said both the French study and the work of Mielke's team "certainly do support the idea that aggressive therapy for vascular disease throughout your whole life span is probably a good idea, and that doesn't change once you have Alzheimer's disease either."
To learn more about Alzheimer's disease, visit the U.S. National Institute on Aging.
Posted: November 2007
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