Background:
Delirium is common, distressing and associated with poor outcomes. Previous studies
investigating the impact of delirium on cognitive outcomes have been limited by
incomplete ascertainment of baseline cognition or lack of prospective delirium
assessments. This study quantified the association between delirium and ...
Background:
Delirium is common, distressing and associated with poor outcomes. Previous studies
investigating the impact of delirium on cognitive outcomes have been limited by
incomplete ascertainment of baseline cognition or lack of prospective delirium
assessments. This study quantified the association between delirium and cognitive
function over time by prospectively ascertaining delirium in a cohort aged ≥65 years in
whom baseline cognition had previously been established.
Methods:
For 12 months, we assessed participants from the Cognitive Function and Ageing
Study II-Newcastle for delirium daily during hospital admissions. At one-year, we
assessed cognitive decline and dementia in those with and without delirium. We
evaluated the effect of delirium (including its duration and number of episodes) on
cognitive function over time, independently of baseline cognition and illness severity.
Results:
82 of 205 participants recruited developed delirium in hospital (40%). One-year
outcome data were available for 173 participants: 18 had a new dementia diagnosis,
38 had died. Delirium was associated with cognitive decline (-1·8 MMSE points [95%
CI -3·5 - -0·2]) and an increased risk of new dementia diagnosis at follow up (OR 8·8
[95% CI 1·9 – 41·4]). More than one episode and more days with delirium (>5 days)
were associated with worse cognitive outcomes.
Conclusions:
Delirium increases risk of future cognitive decline and dementia, independent of illness
severity and baseline cognition, with more episodes associated with worse cognitive
outcomes. Given that delirium has been shown to be preventable in some cases, we
propose that delirium is a potentially modifiable risk factor for dementia.