Risk and prediction of dementia in patients with atrial fibrillation--a nationwide population-based cohort study.

BACKGROUND: Atrial fibrillation (AF) is associated with an increased risk of cognitive impairment and functional decline, and may contribute to development of dementia.

OBJECTIVES: Data from a nationwide large-scale population-based cohort study are lacking. Besides, how best to predict the occurrence of incident dementia among AF subjects remains uncertain.

METHODS: A total of 332,665 AF subjects without dementia were identified as the study group from the "National Health Insurance Research Database" in Taiwan. For each study patient, one age- and sex-matched subject without AF and dementia was selected as the control group. The study end point was occurrence of dementia, and the usefulness of CHADS2 and CHA2DS2-VASc scores in predicting dementia was analyzed.

RESULTS: During the follow-up, 29,012 AF patients experienced dementia with an annual incidence of 2.12%, higher than non-AF subjects (1.50%). Patients with AF possessed a higher risk of dementia with a hazard ratio (HR) of 1.420 after adjustments for age, gender, baseline differences and medication use. Among AF patients, the CHADS2 and CHA2DS2-VASc scores were significant predictors of dementia with an adjusted HR of 1.520 and 1.497 per 1 increment of the CHADS2 and CHA2DS2-VASc scores, respectively. The c-index for CHA2DS2-VASc in predicting dementia (0.611, 95% confidence interval [CI]=0.608-0.614) was significantly higher than the CHADS2 score (0.589, 95% CI=0.586-0.592) (DeLong test p<0.001).

CONCLUSIONS: In this nationwide cohort study, AF was independently associated with a higher risk of dementia. The CHA2DS2-VASc score can be used to estimate the risk of dementia in AF patients.