Some types of antihypertensive medications (AHTs) are more protective against the onset of Alzheimer’s disease (AD) compared to others, and these protective effects vary depending on the race and sex of the patient, according to a new study. For doctors and researchers searching for ways to prevent AD, these findings highlight an important consideration when prescribing and an avenue for future study.
USC Schaeffer Center for Health Policy & Economics researchers Julie Zissimopoulos, Douglas Barthold and colleagues led the study, published in PLOS ONE, which was the first to compare the association between multiple types of blood pressure medications and the risk of acquiring AD across different populations.
They found use of angiotensin-II receptor blockers (ARB) were associated with reduced risk of acquiring AD compared to use of other AHTs for black and white women and white men.
“Alzheimer’s disease is an enormous public health concern and while more than a hundred potential drug treatments are in clinical trials, there are still no treatments available to prevent or slow the progression of the disease. Research is building that AHTs reduce risk of dementia and this study suggests a potential pathway independent of blood pressure effects. All else being equal, for patients who are already being prescribed antihypertensives these findings highlight a potential differential effect on their risk of acquiring Alzheimer’s which a clinician may want to take into account,” said Zissimopoulos who is the director of the aging research program at the USC Schaeffer Center and Vice Dean of Academic Affairs at the USC Price School of Public Policy.
Currently, it is estimated that over 5 million Americans aged 65 and older are living with AD and the number is expected to grow significantly in the coming decades.
Hypertension is one of the most common chronic conditions in the United States, affecting 65 percent of adults over the age of 60. A range of antihypertensive medications are routinely prescribed and have been shown to be very effective in managing their blood pressure.
Furthermore, vascular diseases, and in particular hypertension, have long been recognized as a risk factor for AD and other dementias. What has been less clear is whether the medications used to treat hypertension have an additional protective element against AD beyond lowering blood pressure and for which populations.
“Use of existing drugs could be an inexpensive means to reduce the large and disparate burden of Alzheimer’s disease,” explained lead author Doug Barthold. “By analyzing commonly used prescription drugs in Medicare claims data, we can identify relationships with Alzheimer’s disease onset across diverse populations.” Barthold is a fellow at the Schaeffer Center and a research assistant professor at the University of Washington School of Pharmacy.
Generally speaking, the way antihypertensive medications work can be categorized as either renin-angiotensin system (RAS) acting or non-RAS acting. The RAS is a hormone system that regulates blood pressure and fluid levels in the body.
The researchers analyzed the medical and claims data of Medicare beneficiaries who were prescribed antihypertensives, identifying six different widely used therapeutic classes of AHTs and the patient’s race and sex.
They found a specific type of RAS-acting drugs, angiotensin-II receptor blockers (ARBs), are more protective than other anti-hypertensives, such as ACE inhibitors and four other non RAS-acting classes of drugs. The reduction in risk was strongest for white males, who showed an 18 percent lower risk when using this type of blood pressure medication compared to those using the other non RAS-acting classes of drugs. In addition, ARBs were protective for black and white women. The study found no effect for black men, and Hispanic men and women.
“In prior research we showed that even small delays in the onset of AD and dementia could have significant impacts for the patient, their family and caregivers and the healthcare system more broadly,” said Zissimopoulos. “These findings suggest there may be preventative measures we can take now, which is exciting.”
Given the prevalence of hypertension in older US adults, targeted hypertension treatments that also reduce AD risk could reduce both improve cardiovascular health and contribute to reducing growing burden of AD. The authors note that more studies that include men and women with diverse racial and ethnic backgrounds are needed to confirm the study findings.
Additional study authors include Geoffrey Joyce of the USC Schaeffer Center and School of Pharmacy, Whitney Wharton of Emory University School of Medicine, and Patrick Kehoe of the University of Bristol. The research was supported by the National Institutes of Health awards R01AG055401, RC4AG039036-01, P30AG043073-01, K01AG042498, R01HL126804, and R01HL130462. In addition, Barthold was supported by a Schaeffer-Amgen Fellowship.