Cross‐sectional and longitudinal cognitive trajectories associated with dementia comorbidity clusters: Results from a 10‐year follow‐up real‐world outpatient memory clinic in Brazil

INTRODUCTION: We identified comorbidities associated with dementia and assessed the impact of comorbidity clusters on dementia patients' cognitive trajectories in a real-world Brazilian memory-clinic cohort. METHODS: We analyzed 500 individuals. Ridge-penalized logistic regressions assessed associations between comorbidities and dementia. Tetrachoric correlations and hierarchical clustering informed mixed-effects analyses of longitudinal trajectories. RESULTS: Fazekas score ≥ 2 (odds ratio [OR] 2.48, 95% confidence interval [CI] 1.64-4.54), stroke (OR 2.15, 95% CI 1.23-3.23), alcohol abuse (OR 2.13, 95% CI 1.22-4.92), hearing loss (OR 1.99, 95% CI 1.06-3.94), visual loss (OR 1.94, 95% CI 1.04-4.01), and low education (OR 1.21, 95% CI 1.09-1.54) were associated with dementia cross-sectionally. Comorbidities formed four clusters: cerebrovascular, cardiometabolic, neurosensory, substance abuse. Higher cerebrovascular burden predicted a 158% faster rate of cognitive decline in individuals with dementia. DISCUSSION: Our findings show four dementia comorbidity clusters and identify cerebrovascular burden as a prognostic marker of faster cognitive decline.