Dementia patients live a median of 4.5 years following the estimated onset of the condition, with male, older, and disabled patients having a significantly shorter survival time, according to a population study published online in BMJ.
The large multicenter study of English and Welsh patients found that those who were aged 65–69 years at dementia onset survived a median of 10.7 years, nearly three times the 3.8 years seen in patients with disease onset at age 90 or later (BMJ 2008 Jan. 11 [Epub doi:10.1136/bmj.39433.616678.25]).
Researchers said their study provides the first estimate of survival times for dementia patients in England and Wales.
“Some of these results may seem self-evident but they answer questions asked by those caring for and advising people with dementia,” wrote the researchers, led by Jing Xie, research associate with the Cambridge (England) University Institute of Public Health.
The analysis involved 13,004 patients taking part in the Medical Research Council's longitudinal cognitive function and aging study in England and Wales in 1991–2003. Participants were assessed for dementia at regular intervals. A total of 438 patients developed dementia by 2003 and were followed until Dec. 31, 2005. Of these 438 patients, 70% were women. They had a median age of 84 at dementia onset. A total of 356 dementia patients had died by the end of 2005; their median age at death was 89.
The investigators found a greater adjusted risk of death for men, compared with women (hazard ratio 1.4). In addition, disability with dementia was associated with a 3-year reduction in survival between the most and least functionally impaired. (Those who scored in the bottom third of the Blessed dementia scale had a hazard ratio for death of 2.1, compared with those in the top third.)
Hazard ratios for death were 2.7 in those aged 80–89 years at dementia onset and 3.1 in those aged 90 and older, compared with those aged 65–69.
The researchers found no difference in survival based on marital status, accommodation type (living in the community or residential home), self-reported health, score on Mini-Mental State Examination, educational status, or socioeconomic class.
In an accompanying editorial Murna Downs, Ph.D., of the University of Bradford (England) Dementia Group and Barbara Bowers, Ph.D., of the University of Wisconsin, Madison, nursing school wrote, “The 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” (BMJ 2008 Jan. 11 [Epub doi:10.1136/bmj.39433.616678.25]).