失智症發生後存活時間的重新評估

A Reevaluation of the Duration of Survival after the Onset of Dementia

王用亨(Yung-Hung Wang)

《台灣老年醫學雜誌》 1卷4期 (2006/05) Pp. 267-269

並列摘要

Background: Dementia shortens life expectancy; the median survival after the onset of dementia is estimated to fall in the range from 5 to 9.3 years. Previous studies of people with existing dementia, however, may have underestimated the deleterious effects of dementia on survival by failing to consider persons with rapidly progressive illness who died before they could be included in a study (referred to as length bias).
Methods: The research used data from the Canadian Study of Health and Aging to estimate survival from the onset of symptoms of dementia; the estimate was adjusted for length bias. A random sample of 10,263 subjects 65 years old or older throughout Canada was screened for cognitive impairment. For those with dementia, we ascertained the date of onset and conducted follow-up for five years.
Results: We analyzed data on 821 subjects, of whom 396 had probable Alzheimer's disease, 252 had possible Alzheimer's disease, and 173 had vascular dementia. For the group as a whole, the unadjusted median survival was 6.6 years (95 percent confidence interval, 6.2 to 7.1). After adjustment for length bias, the estimated median survival was 3.3 years (95 percent confidence interval, 2.7 to 4.0). The median survival was 3.1 years for subjects with probable Alzheimer's disease, 3.5 years for subjects with possible Alzheimer's disease, and 3.3 years for subjects with vascular dementia.
Conclusions: Median survival after the onset of dementia is much shorter than previously estimated.