The average life expectancy of people diagnosed with dementia ranges from 9 years at age 60 to 4.5 years at age 85 for women and from 6.5 to just over 2 years, respectively, for men, finds a systematic review the latest on The BMJ today.
The results also suggest that a third of people with dementia are admitted to a nursing home within three years of diagnosis.
Nearly 10 million people worldwide are diagnosed with dementia each year, but survival estimates vary widely and few studies have assessed prognosis (the likely course of the condition) in terms of time to nursing home admission.
To better understand this, researchers in the Netherlands set out to determine the prognosis for people diagnosed with dementia, both in terms of remaining life expectancy and time to nursing home admission.
Their findings are based on 261 studies published between 1984 and 2024 (235 on survival and 79 on nursing home admission) involving more than 5 million people with dementia (mean age 79 years, 63% women).
The studies were mainly from Europe and North America with a mean follow-up time of 7 years.
After assessing study quality, the researchers found that median survival from diagnosis appeared to be highly dependent on age, ranging from 8.9 years at a median age of 60 for women to 2.2 years at a median age of 85 for men.
Overall, dementia reduced life expectancy by about two years for those diagnosed at age 85, 3-4 years at diagnosis at age 80, and up to 13 years at diagnosis at age 65.
Median survival was up to 1.4 years longer in Asian populations and 1.4 years longer among people with Alzheimer’s disease compared with other types of dementia.
The average time to nursing home admission was just over 3 years, with 13% of people admitted in the first year after diagnosis, rising to a third (35%) at three years and more than half (57%) at five years. However, the authors note that these estimates are less reliable and should be interpreted with caution.
These are observational findings, and the authors acknowledge that differences in study methods and inconsistent reporting of measures such as socioeconomic status, race, disease severity, and preexisting conditions may have influenced their estimates.
However, they point out that the rigorous search and data extraction enabled the largest number of studies to date to be analyzed over an extended period, “offering potential for personalized prognostic information and care planning.”
They conclude: “Future studies on personalized prognosis should ideally include patients at the time of diagnosis, taking into account personal factors, social factors, disease stage and comorbidity, while assessing relevant functional outcome measures on and beyond mere survival’.
In a related article, researchers from Norway say that although the understanding of survival with dementia has advanced significantly, the complexities of predicting the timing of nursing home admission remain.
“To improve future healthcare services and optimize quality of life for people with dementia and their families, it is important to continue to strive for more accurate, context-sensitive knowledge,” they conclude.
