Most patients with Down’s syndrome will have dementia at the time of death
medwireNews: Dementia is the proximate cause of death in 70% of older adults with Down’s syndrome (DS), show findings from a large community-based study published in JAMA Neurology.
Data from the London Down Syndrome Consortium cohort for 211 participants with DS aged 35 years or older showed a crude mortality rate for the 66 individuals diagnosed with dementia of 1191.85 deaths per 10,000 person–years, which was fivefold higher than the 232.22 deaths per 10,000 person–years rate for those without dementia.
Commenting on this in a related editorial, Michael Rafi (University of Southern California, San Diego, USA) and Stephanie Santoro (Harvard Medical School, Boston, Massachusetts, USA), note: “By comparison, in the general population, dementia of any subtype is listed in only 18% of death certificates for those older than 65 years, with mortality rates being slightly less than 2-fold higher in those with dementia than those without.”
Given the finding that most older adults with DS will have dementia at the time of death, the editorialists suggest that there is “a greater need for individuals and families of adults with DS to plan for a life stage with dementia”, adding that “physicians and health care systems may consider adopting practice standards that incorporate screening for dementia and epilepsy in older adults with DS.”
In all, 11 of 96 women and 16 of 115 men with DS died during follow-up. Of those who died, nine (81.8%) women and 10 (62.5%) men had dementia. The median age at death was 55 years for those with dementia versus 57 years for those without. The researchers also note that at least three of the eight participants who died without dementia showed signs of cognitive decline or had seizures.
Rosalyn Hithersay (King’s College London, UK) and team write in JAMA Neurology that this makes patients with DS “a vital population for researching disease progression, modifying factors, and potential treatments.”
Apolipoprotein E (APOE) status was the only factor significantly associated with mortality in patients with DS and dementia, with APOE ε4 carriers found to have a sevenfold increased risk for death compared with APOE ε3 carriers.
Earlier diagnosis of dementia was more likely for APOE ε4 carriers (hazard ratio [HR]=4.9), adults with early-onset epilepsy (HR=3.6), and for those with multiple health comorbidities (HR=2.0) and who were living with family (HR=2.1).
There were no differences in mortality or dementia diagnosis between men and women, after taking into account apolipoprotein E (APOE) genotype, multimorbidity, living situation and early-onset epilepsy.
Among those without dementia, onset of epilepsy after the age of 36 years was the only significant factor associated with death, increasing the risk 10-fold.
The researchers conclude: “[W]e hope that our findings can improve clinical care by identifying factors associated with increased risk for dementia and mortality risk in this population, suggesting the potentially beneficial effects of existing medication options and helping clinicians provide prognostic information for their patients with DS.”
By Lucy Piper
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