Objective: Vascular dementia (VaD) and Alzheimer's disease with cerebrovascular disease (AD+CVD) are the leading causes of dementia after Alzheimer's disease alone (AD). Little is known about the progression of either VaD or AD+CVD. The aim of this study was to compare demographic features, cognitive decline and survival of patients with VaD, AD+CVD and AD alone attending a memory clinic.
Methods: This study included 970 patients who were followed at the Lille-Bailleul memory clinic, France. Cognitive functions were measured with the Mini Mental State Examination (MMSE) and the Dementia Rating Scale (DRS). Survival rate was analysed with a left-truncated Cox model. Analyses were adjusted for age, sex, education, hypertension, diabetes and baseline MMSE and DRS.
Results: Of 970 patients, 141 had VaD, 663 AD alone and 166 AD+CVD. The latter were significantly older than AD or VaD patients at onset (71±7 vs. 69±9 and 68±9 years, p=0.01) and at first visit (75±6 vs. 73±8 and 72±8 years, p=0.0002). Baseline MMSE and DRS evaluations were highest for VaD compared with AD alone or AD+CVD patients (p<0.006). Cognitive decline during follow-up was slowest for VaD, intermediate for AD+CVD, and fastest for AD alone (p=0.03). After adjustment, compared with AD patients, mortality risk was similar for those with VaD (RR=0.7[0.5-1.1]) and tended to be lower for AD+CVD (RR=0.7[0.5-1.0]). The shorter the delay between first symptoms and first visit, the longer patients survived.
Conclusion: This clinical cohort study shows that patients with VaD, AD+CVD and AD present different characteristics at baseline and during follow-up and underlines the need to distinguish between them.