Differences by drug type
Results differed in accordance with antihypertensive class. Angiotensin II receptor blockers decreased the odds of Alzheimer’s disease neuropathology by 40% (OR, 0.60; P < .5). Diuretics decreased the odds of Alzheimer’s disease by 36% (OR, 0.64; P < .001) and of hippocampal sclerosis by 32% (OR, 0.68; P < .5).
“We see diuretics are a main driver, especially for lower odds of Alzheimer’s disease and lower odds of hippocampal sclerosis,” said lead author Hanna L. Nguyen, a first-year medical student at the University of California, Irvine.
The results indicate that it is the medications, not BP levels, that account for these associations, she added.
One potential mechanism linking antihypertensives to brain pathology is that with these agents, BP is maintained in the target zone. Blood pressure that’s too high can damage blood vessels, whereas BP that’s too low may result in less than adequate perfusion, said Ms. Nguyen.
These medications may also alter pathways leading to degeneration and could, for example, affect the apo E mechanism of Alzheimer’s disease, she added.
The researchers plan to conduct subset analyses using apo E genetic status and age of death.
Although this is a “massive database,” it has limitations. For example, said Dr. Sajjadi, it does not reveal when patients started taking BP medication, how long they had been taking it, or why.
“We don’t know the exact the reason they were taking these medications. Was it just hypertension, or did they also have heart disease, stroke, a kidney problem, or was there another explanation,” he said.
Following the study presentation, session comoderator Krish Sathian, MBBS, PhD, professor of neurology, neural, and behavioral sciences, and psychology and director of the Neuroscience Institute, Penn State University, Hershey, called this work “fascinating. It provides a lot of data that really touches on everyday practice,” inasmuch as clinicians often prescribe antihypertensive medications and see patients with these kinds of brain disorders.
The investigators and Dr. Sathian reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.