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Atrial fibrillation associated with cognitive impairment

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f1473 (Published 06 March 2013) Cite this as: BMJ 2013;346:f1473

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Meta-analysis of 21 observational studies has confirmed that atrial fibrillation is associated with cognitive impairment and dementia. Atrial fibrillation was linked to cognitive impairment in adults with or without a history of stroke (14 studies; relative risk 1.40, 95% CI 1.19 to 1.64). It was also linked to cognitive impairment in a series of further analyses confined to studies of adults without stroke, prospective studies, cross sectional studies, and studies of cognitive impairment after stroke. Atrial fibrillation was also associated with clinical dementia (1.38, 1.22 to 1.56) and with cognitive impairment defined by scores on the mini-mental state examination (MMSE).

Study quality was variable. About half the prospective studies controlled for confounding but used a variety of different methods to measure, define, and capture atrial fibrillation and cognitive impairment or dementia.

The authors are fairly confident that the association is independent of stroke but less confident about the role of shared risk factors such as diabetes, heart failure, and hypertension. We need well designed and well controlled longitudinal studies to explore the precise mechanism linking these two common clinical problems, they write. Trialists evaluating treatments for atrial fibrillation should also consider cognitive function as an outcome.

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Cite this as: BMJ 2013;346:f1473