# Factors impacting survival in individuals with Down syndrome‐associated Alzheimer's disease

## TL;DR

People with Down syndrome who develop Alzheimer's disease tend to live shorter lives, but those in specialized care and those without late-onset epilepsy live longer.

## Contribution

This study identifies specialist care and late-onset epilepsy as key factors affecting survival in individuals with Down syndrome-associated Alzheimer's disease.

## Key findings

- Individuals with Down syndrome in specialist intellectual disability dementia care had a mean survival of 9.5 years after AD diagnosis.
- Late-onset myoclonic epilepsy in Down syndrome was linked to a threefold higher risk of death after onset.
- Mean survival after AD diagnosis in Down syndrome was 4.8 years, with shorter survival in community or residential care settings.

## Abstract

Adults with Down syndrome (DS) are at high risk for Alzheimer's disease (AD), the leading cause of death in this population. Survival in DS after AD diagnosis appears shorter than in sporadic AD; however, the factors influencing survival remain poorly understood.

We analyzed 157 adults with DS from Spain and Ireland who died of AD between 2012 and 2024. Clinical, genetic, and care predictors were examined using Kaplan–Meier curves and Cox regression.

Mean survival after AD diagnosis was 4.8 years (SD 3.5). Those in specialist intellectual disability dementia care had a longer survival time (mean 9.5 years) than other settings (mean 3.4 to 4.1 years; p < 0.001). Late‐onset myoclonic epilepsy in DS (LOMEDS) was linked to a threefold higher risk of death after onset (p < 0.001).

Specialist care settings and LOMEDS timing significantly shape survival in DS‐associated AD, highlighting the importance of tailored services and proactive epilepsy treatment.

Mean survival after DSAD dementia diagnosis in a multicenter cohort was 4.8 years.People with DS in specialist ID dementia care lived the longest, 9.5 years.People with DS in community, residential, or nursing care facilities lived 3.4 to 4.1 years.LOMEDS was associated with a threefold higher risk of death after onset (HR 3.37).Findings support specialist ID and dementia care and support.

Mean survival after DSAD dementia diagnosis in a multicenter cohort was 4.8 years.

People with DS in specialist ID dementia care lived the longest, 9.5 years.

People with DS in community, residential, or nursing care facilities lived 3.4 to 4.1 years.

LOMEDS was associated with a threefold higher risk of death after onset (HR 3.37).

Findings support specialist ID and dementia care and support.