A reevaluation of the duration of survival after the onset of dementia.


Journal Article

BACKGROUND: Dementia shortens life expectancy; estimates of median survival after the onset of dementia have ranged 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: We 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 from 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 has previously been estimated.

Full Text

Duke Authors

Cited Authors

  • Wolfson, C; Wolfson, DB; Asgharian, M; M'Lan, CE; Ostbye, T; Rockwood, K; Hogan, DB; Clinical Progression of Dementia Study Group,

Published Date

  • April 12, 2001

Published In

Volume / Issue

  • 344 / 15

Start / End Page

  • 1111 - 1116

PubMed ID

  • 11297701

Pubmed Central ID

  • 11297701

International Standard Serial Number (ISSN)

  • 0028-4793

Digital Object Identifier (DOI)

  • 10.1056/NEJM200104123441501


  • eng

Conference Location

  • United States