It’s Not Just About Cardiovascular Disease. Lowering Blood Pressure Reduces All-Cause Dementia

An intensive program to lower blood pressure was associated with 15%decrease in dementia from all causes, according to results from presented Saturday at the American Heart Association Scientific Sessions meeting in Philadelphia.

Although dementia is commonly viewed as consequences of neurological changes in the brain, it can also be caused by vascular disease.

“I think a lot of what is called Alzheimer’s is probably vascular dementia,” said Sandra J. Taler, M.D., a professor of medicine at the Mayo Clinic in Rochester, Minnesota, and a hypertension expert, at a press briefing about late-breaking abstracts about hypertension at the meeting.

The blood pressure-lowering program, which was conducted in China, had the interesting feature of having “trained village doctors” — they would be called community health workers in other contexts — work with patients on taking antihypertensive medications. Keith C. Ferdinand, M.D., a professor at Tulane University School of Medicine and a discussant of this and several other studies at the press briefing, mentioned that community health workers in the U.S. might be used in a similar fashion.

Jiang He, M.D., Ph.D.

The program to lower pressure was assessed in a trial that randomized villages rather than individuals. Jiang He, a professor of epidemiology at the Tulane School of Public Health & Tropical Health, and his colleagues randomized assigned 163 villages to the blood pressure-lowering program and the same number to usual care. The people in those villages eligible to be enrolled in the program were age 40 or older and had either had untreated blood pressure of 140/90 mm Hg or higher; a high risk of cardiovascular disease and blood pressure of 130/80 mm Hg or greater; or were taking a hypertensive. A total 33,995 people were enrolled.

In the intervention villages, trained village doctors followed a stepped-care protocol with the goal of achieving a blood pressure of 130/80 mm Hg, a common goal for blood pressure. In the control villages, usual was delivered,

At 48 months, the average blood pressure among the people in the intervention group was 127.6/72.6 mm Hg; in the usual care villages it was 147.7/81 mm Hg. The systolic blood pressure of the people in the intervention villages who were enrolled in the study dropped an average of 22 mm Hg and diastolic decreased by 9.3 mm Hg.

Neurologists who were blinded to the villages’ assignment conducted cognitive status assessments. They identified 668 cases of all-cause dementia in the blood pressure-lowering villages, which was calculated to be a rate of 1.12% per year compared with 734 in the usual care villages and a rate of 1.31% per year. The relative risk of the rates works out to be a 15% difference favoring the intervention group.

The relative risk was roughly the same for cognitive impairment with no dementia; dementia or cognitive impairment; and dementia or deaths.

Taler said that results from a large, blood pressure-lowering trial conducted in the U.S. and funded by the National Institutes of Health called SPRINT hinted at a dementia benefit from lowering blood pressure, but it was just a signal because of the number of people enrolled in the study and that it was stopped early after the cardiovascular benefits were certain

Taler spoke about the difficulties of mounting a randomized controlled trial of blood pressure-lowering and dementia in the U.S.: “How tightly do you treat the blood pressure? And then you have to have the follow-up and you probably need some involved battery of testing or imaging, or both. And that gets expensive. And I don’t think you want to tie to a certain drug.”