Dementia in patients with atrial fibrillation and the value of the H achinski ischemic score

Aim To assess the prevalence of vascular dementia, mixed dementia and A lzheimer's disease in patients with atrial fibrillation, and to evaluate the accuracy of the Hachinski ischemic score for these subtypes of dementia. Methods A nested case–control study was carried out. A total of 103 of 784 consecutive patients evaluated for cognitive status at the A mbulatory G eriatric C linic had a diagnosis of atrial fibrillation. Controls without atrial fibrillation were randomly selected from the remaining 681 patients using a 1:2 matching for sex, age and education. Results The prevalence of vascular dementia was twofold in patients with atrial fibrillation compared with controls (21.4% vs 10.7%, P  = 0.024). Alzheimer's disease was also more frequent in the group with atrial fibrillation (12.6% vs 7.3%, P  = 0.046), whereas mixed dementia had a similar distribution. The H achinski ischemic score poorly discriminated between dementia subtypes, with misclassification rates between 46% (95% CI 28–66) and 70% (95% CI 55–83). In patients with atrial fibrillation, these rates ranged from 55% (95% CI 32–77) to 69% (95% CI 39–91%). In patients in whom the diagnosis of dementia was excluded, the Hachinski ischemic score suggested the presence of vascular dementia in 11% and mixed dementia in 30%. Conclusions Vascular dementia and A lzheimer's disease, but not mixed dementia, are more prevalent in patients with atrial fibrillation. The discriminative accuracy of the Hachinski ischemic score for dementia subtypes in atrial fibrillation is poor, with a significant proportion of misclassifications. Geriatr Gerontol Int 2015; 15: 770–777.