A new study by British researchers finds that on average, people who are diagnosed with incident dementia survive for a median of 4.5 years, but survival varied between 10.7 and 3.8 years for those diagnosed in their 60s vs their 90s. Sex and disability prior to dementia onset also affected survival times.
“Our analyses provide robust population-based estimated survival for incident dementia by age, sex, and setting,” the researchers, with senior author Carole Brayne, MD, from the Institute of Public Health, University of Cambridge, United Kingdom, conclude. While some of these findings may seem “self-evident,” the authors write, “they answer questions asked by those caring for and advising people with dementia. We hope the estimates will be valuable to patients, clinicians, carers, service providers, and policy makers.”
The findings, from the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS), were published January 10 in the BMJ.
Doubling Dementia
Life expectancy is increasing globally, with 1 consequence being increasing numbers of people affected by dementia, the authors write. It is estimated that the numbers of those with dementia will double every 20 years, to some 81.1 million by 2040, they note.
One question asked frequently in both clinical and policy settings is the impact of dementia on life expectancy, they write. In the present study, the authors examined overall survival for people with dementia, as well as the association between factors that could affect survival in incident cases of dementia over a 14-year follow-up.
MRC CFAS is a multicenter, longitudinal, prospective population-based epidemiological study of cognitive function and disability in England and Wales, including 2 urban and 3 rural centers. The study included 13,004 individuals aged 65 years or older who were drawn from primary care population registers; at each study visit, information on sociodemographic factors, cognitive function, health conditions, and self-reported health were recorded. Participants were enrolled and followed over time for dementia status and mortality.
Of 438 subjects who developed dementia between 1991 and 2003, 356, or 81%, had died by December 2005.
The estimated median survival time from the onset of dementia to death was 4.5 years for the overall population but slightly longer for women than men, with a median survival of 4.6 vs 4.1 years.
Age at onset of dementia had a significant effect on survival times; “There was a difference of nearly 7 years in survival between the younger old and the oldest people with dementia,” the authors write.
Estimated Median Survival by Age at Dementia Onset
|
Age at Dementia Onset (y)
|
Survival (y)
|
|
65 – 69
|
10.7
|
|
70 – 79
|
5.4
|
|
80 – 89
|
4.3
|
|
> 90
|
3.8
|
Disability with dementia was also associated with shorter survival even after other factors were taken into account, the authors note, with an absolute reduction in survival of about 3 years between the most and least disabled. “This does suggest that the frailer individuals are at higher risk even after age is considered,” they write.
Consider Human Worth
In an editorial accompanying the paper, Murna Downs, PhD, from the Bradford Dementia Group, University of Bradford, United Kingdom, and Barbara Bowers, PhD, from the University of Wisconsin School of Nursing, in Madison, point out that this study shows that dementia “is a terminal condition, the course of which unfolds with coexisting age, related impairment, and ill health.”
The present study provides clear evidence that people with dementia need coordinated care and support from a range of professionals and practitioners “from diagnosis to death” to ensure maximum quality of life and prevent unnecessary disability and suffering, they write. Doctors should also be aware of a “growing evidence base for therapeutic intervention and effective support” in achieving those goals.
“In planning care and support, doctors need to pay as much attention to the essential human worth of a person with dementia and their retained capacity for relationships, pleasure, communication, and coping as they do to deficits and dysfunction,” they conclude.
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