HeartRhythm: A-fib increases dementia risk, including Alzheimer's

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Patients with atrial fibrillation (AF) may have a greater risk of developing dementia, researchers have found. And while Alzheimer's disease most commonly occurs in the older patient population, in those with AF, patients 70 years old and younger may pose the greatest risk, based on study results published in the April issue of the Heart Rhythm Journal.

T. Jared Bunch, MD, of the Intermountain Medical Center in Murray, Utah, and colleagues evaluated 37,025 patients to measure the association between AF and subgroups of dementia. According to the authors, Alzheimer's disease (AD) is found in 60 to 80 percent of patient cases specific to dementia and most common in the elderly population.

Additionally, the authors wrote that like dementia, AF increases with age and  “dementia and AF share similar background risk factors.”

In addition, AF has been linked to “memory impairment, cognitive decline, and general dementia in patients without pre-existing disease,” the researchers said.
While comparing the association between AF and AD, the researchers also evaluated the impact that AF had on patients diagnosed with AD, in regard to mortality.

The researchers drew from data within the Intermountain Heart Collaborative Study database. Patients average age was 60.6 years and had no pre-existing dementia or AF. They broke down dementia into variant subgroups including AD, vascular dementia, senile dementia and non-specified dementia.

Of the 37,025, 27 percent (10,161 patients) developed AF, while 4.1 percent (1,535 patients) developed dementia. After a five-year follow-up, of those who developed dementia, 179 developed vascular dementia, 321 developed senile dementia, 347 developed AD and 688 developed non-specified dementia.

In addition, the researchers found that for all subgroups of dementia, “cognitive decline occurred earlier in patients with AF versus no AF.”

Overall, Bunch et al found that 764 patients developed both AF and dementia, and AF developed before dementia. However, the researchers said that “the dementia diagnosis could have occurred simultaneously with AF or after AF diagnosis.”

Additionally, researchers found an association between dementia and mortality and found that death occurred more frequency within the younger patient group (70 years or younger), but was found to be insignificant in the older group.

“While age remains the strongest risk factor for dementia, our study shows the highest risk of Alzheimer’s and other dementia types was most prominent in the youngest AF patient group,” Bunch noted. “This finding is significant in establishing the association between dementia and AF and could potentially help clinicians monitor patients more closely for signs of dementia and mortality risks,” Bunch concluded.