Seven-year survival rate after age 85 years: relation to Alzheimer disease and vascular dementia

Abstract

Objective: To investigate the survival rate in very elderly individuals in relation to Alzheimer disease, vascular dementia, and other mental and physical disorders.

Design: A 7-year longitudinal survey.

Setting: Community and institutions in Gothenburg, Sweden.

Participants: A representative sample of 494 people aged 85 years.

Main outcome measures: Results of neuropsychiatric and physical examinations, key informant interview, and computed tomographic scan of the head. Information on mortality was obtained from the parish office.

Results: The 7-year survival rate was higher in women (34.5%) than in men (20.3%). Alzheimer disease and vascular dementia predicted 30.7% of deaths in men and 49.7% of deaths in women according to a calculation of population attributable risk (PAR). A regression analysis showed that mortality in men was predicted by the presence of chronic obstructive lung disease (PAR, 18.8), Alzheimer disease (PAR, 16.0), vascular dementia (PAR, 14.7), cancer of the gastrointestinal tract (PAR, 10.2), and skin cancer (PAR, 6.2), and in women by vascular dementia (PAR, 29.4), Alzheimer disease (PAR, 20.3), cerebrovascular disorder (PAR, 12.1), congestive heart failure (PAR, 8.5), hypertension (PAR, 8.0), myocardial infarction (PAR, 6.5), and cancer of the gastrointestinal tract (PAR, 4.3). Life expectancy decreased with severity of dementia, although survival time in individuals with mild Alzheimer disease was not different from that in individuals without dementia.

Conclusions: In extreme old age, Alzheimer disease and vascular dementia influence the mortality rate considerably. However, mild Alzheimer disease does not influence longevity, at least not during the first 7 years. These findings have important public health implications.