Risk of dementia in stroke-free patients diagnosed with atrial fibrillation: data from a community-based cohort.

AIMS To estimate the incidence of dementia after the first atrial fibrillation (AF), and its impact on survival in a community-based cohort. METHODS AND RESULTS Olmsted County, Minnesota adult residents diagnosed with first AF during 1986-2000 were identified, and followed until 2004. The primary outcome was new detection of dementia. Interim stroke was censored in the analyses. Of 2837 subjects (71 +/- 15 years old) diagnosed with first AF and without any evidence of cognitive dysfunction or stroke at the time of AF onset, 299 were diagnosed with dementia during a median follow-up of 4.6 years [interquartile (IQR) range 1.5-7.9 years], and 1638 died. The Kaplan-Meier cumulative rate of dementia was 2.7% at 1 year and 10.5% at 5 years. After adjustment for age and sex, dementia was strongly related to advancing age [hazard ratio (HR)/10 years, 2.8; 95% confidence interval (CI), 2.5-3.2], but did not vary with sex (P = 0.52). The occurrence of post-AF dementia was associated with significantly increased mortality risk (HR 2.9; 95% CI 2.5-3.3), even after adjustment for multiple comorbidities, and did not vary with age (P = 0.75) or sex (P = 0.33). CONCLUSION Dementia appeared common following the diagnosis of first AF, and was associated with premature death.