Alzheimer's disease progression in the oldest old compared to younger elderly patient: data from the REAL.FR study.

OBJECTIVE: Although population-based studies have revealed marked increases in the prevalence and incidence of dementia, particularly in older age groups, longitudinal studies of cognitive change have been less frequently conducted. The aim of this study is to describe the progression of Alzheimer's disease (AD) in the oldest old (>or=85 years) and to compare it with the younger elderly.

METHODS: A cohort of 114 AD patients >or=85 years old and 572 AD patients <85 years living in the community at inclusion were monitored over 2 years in 16 centers of the French AD network (REAL.FR study). Each subject underwent extensive medical examination including functional (Activities of Daily Living or ADL) and neuropsychological evaluations (including Mini Mental Status Evaluation or MMSE) every 6 months.

RESULTS: The observed decrease in MMSE performance in patients >or=85 was -4.18 +/- 0.63 points during the 2-year follow-up (vs -4.62 +/- 0.25 in the younger group) with no statistically significant differences between the two groups. After adjusting for confounding factors, ADL score declined faster in the oldest old than in individuals <85 years old during the 2-year follow-up: -1.73 +/- 0.19 vs -1.27 +/- 0.08 (p = 0.0309).

CONCLUSIONS: Our study showed, that while the progression of cognitive impairment was identical in both groups, after adjustment for variables related both to age and dependency, the progression of dependency was more rapid in those over 85 years old.