Patients with atrial fibrillation are more likely to develop dementia, a meta-analysis confirms, regardless of stroke history. Pooling the results of 14 studies, researchers found the risk of cognitive impairment was 40% greater in patients with AF.
The increased risk existed regardless of whether subjects had a history of stroke. But the risk was nearly tripled in patients who had both AF and stroke, the researchers reported after examining a further seven studies.
Both cognitive impairment and dementia showed similar increases in risk with AF, the authors concluded in the Annals of Internal Medicine.
Dementia, cognitive impairment, and AF share similar risk factors, including age, hypertension, congestive heart failure and diabetes, the authors said.
This could explain the association between them, but also meant that dealing with confounding variables was important. However there could be other mechanisms at play, they wrote.
Patients with AF might be in a “hypercoagulable state” or thrombi in the left atrial appendage might be thrown out, leading to clinical and subclinical strokes.
Stroke was self-reported in many of the studies and not confirmed by scans, meaning the meta-analysis could not rule out silent stroke could be the cause.
Brain hypoperfusion due to beatto-beat variability, the proinflammatory state in AF and the periventricular white-matter lesions might
also explain the link, the authors said, but these remain untested.
Longitudinal studies, with careful adjustment for confounders, were needed to clarify the nature of the association, they concluded.
Article first published in Neurology Update March 05