ARBs reduce dementia risk, study suggests

Angiotensin receptor blockers (ARBs), commonly used as therapy for hypertension and cardiovascular disease (CVD), may offer protection against Alzheimer’s disease (AD) and dementia, according to research published in the British Medical Journal.

The research also noted that compared to angiotensin converting enzyme (ACE) inhibitors or other heart disease medicines, ARBs appeared to provide better protection against AD and dementia.

The study was the first to compare both the risk of dementia and progression of dementia in users of ARBs to users of an ACE inhibitor (lisinopril) or users of other drugs prescribed for CVD, wrote lead author Professor Benjamin Wolozin, of the Boston University School of Medicine, and colleagues, who conducted the study. Wolozin noted that they also compared ARBs to a cohort consisting of users of any ACE inhibitor (not concurrently using ARBs) and obtained similar results.

The authors explained that they chose lisinopril because it had the most number of users and the longest history of use, and that they examined a comparator group that used other ACE inhibitors in order to control for potential biases linked to the selection of one particular ACE inhibitor.

Dr. Nagaendran Kandiah, a consultant neurologist at the National Neuroscience Institute in Singapore, called the study findings “a big thing,” considering the number of patients suffering from dementia.

“In the Asia-Pacific region alone, there are currently 14 million patients with dementia and this will increase to 25 million by 2020. Other studies have shown that by delaying the onset of dementia by 2 years we can reduce future prevalence of dementia by 15 to 20 percent. This will have a huge economic impact on healthcare costs.”

But he noted that the study’s retrospective nature was a limitation. “If the findings are reproduced in prospective studies, ARBs will have a major role in the prevention of dementia,” said Kandiah, noting however that many studies had shown benefits in dementia, but without reproducible results.

“For example, cholesterol lowering agents were initially shown to have good results in preventing dementia in retrospective studies, but the same results could not be reproduced in prospective studies,” he explained.

Researchers analyzed 2002 to 2006 data from the US Veteran Affairs database. Their findings were based on 819,491 mainly male subjects (98 percent) aged 65 or above with CVD. Researchers grouped this population into three cohorts – subjects taking ARBs, subjects taking the ACE inhibitor lisinopril, and those taking cardiovascular medications such as beta blockers and calcium channel antagonists. They then looked at the time to incident AD or dementia in the three cohorts over a timeframe of 4 years. Researchers also looked at disease progression defined as the time to nursing home admission or mortality in subjects who were already diagnosed with AD or dementia.

The authors reported that ARBs significantly reduced the risk of incident AD compared to lisinopril (HR 0.81, 95% CI 0.68 to 0.96, P=0.016) or the cardiovascular comparator (HR 0.84, 95% CI 0.71 to 1.00, P=0.045).

ARBs also significantly reduced incident dementia compared to lisinopril (HR 0.81, 95% CI 0.73 to 0.90, P<0.001) or the other cardiovascular drugs (HR 0.76, 95% CI 0.69 to 0.84, P<0.001).

ARB-use in patients with pre-existing AD significantly reduced risk of nursing home admission (HR 0.51, 95% CI 0.36 to 0.72, P=0.0001) and death (HR 0.83, 95% CI 0.71 to 0.97, P=0.022) compared to the cardiovascular comparator. The results were similar for dementia patients. [BMJ 2010;340:b5465]

Source: mims.com