From Heartwire

New AF Predicts Diagnosis of Alzheimer's, Other Dementias

Steve Stiles

Authors and Disclosures

Print This Email this

April 7, 2010 (Murray, Utah) — Onset of atrial fibrillation (AF) in a community population followed for five years predicted development of dementia of any kind during the same period, and it also predicted each of four dementia subtypes independently, including Alzheimer's disease [1].

The relationship of new AF to Alzheimer's was significant only among patients who were younger at baseline, report Dr T Jared Bunch (Intermountain Medical Center, Murray, UT) and colleagues in the April 2010 issue of Heart Rhythm. The arrhythmia was also a predictor of mortality among people who developed dementia.

Of 37 025 patients in the cohort from a regional medical group, who were predominantly white and without preexisting AF or dementia, 27% developed the arrhythmia and 4.1% were diagnosed with some form of dementia over a mean of five years.

Significantly more AF patients than non-AF patients developed each of four types of dementia as defined by ICD-9 codes (p<0.0001>

In multivariate analyses, those developing AF had an odds ratio (OR) of:

• Only 1.06 (p=0.59) for developing Alzheimer's regardless of age, but it was 2.30 (p=0.001) among those <70 years; ORs weren't significant in any older age group by decade.
• 1.44 overall for nonspecific dementia and 2.87 among patients <70 (p<0.0001 p="0.001).">
• 1.39 overall (p=0.005) for senile dementia; it was 3.34 in the <70 group and 1.60 in those aged 70 to 79 (p<0.0001 p="">

Overall, development of dementia independently increased hazard ratio (HR) for mortality, at p<0.0001><70>

Why AF and the different forms of dementia were linked is unknown, Bunch et al observe, but they list a few possible mechanisms. Dementia and AF could share a common predisposing condition, such as central hypertension or microvascular dysfunction. Perhaps heart failure associated with AF compromises cerebral perfusion. Or, the group speculates, "AF independently increases systemic inflammation beyond other cardiac risk factors and may thereby accelerate the inflammation-mediated progressive cognitive decline."

Bunch and coauthors Drs J Peter Weiss, Brian G Crandall, and Jeffrey S Osborn (all of Intermountain Medical Center) report receiving honoraria from Boston Scientific. Dr John D Day (Intermountain Medical Center) reports consulting for Boston Scientific and St Jude Medical.