ICU admission tied to dementia risk

Older adults who have been admitted to the intensive care unit (ICU) may have an elevated risk of developing Alzheimer’s dementia or all types of dementia, according to a study presented at AAIC 2022.

“We found that ICU hospitalization was associated with double the risk of dementia in community-based older adults [compared with those who did not experience ICU hospitalization],” said study author Associate Professor Bryan D. James from the Rush Alzheimer’s Disease Center (RADC) and Rush Medical College, Chicago, Illinois, US.

“This could potentially mean that ICU hospitalizations are an unexamined risk factor for dementia,” he added.

Data for this study were obtained from five cohorts* in the Rush Alzheimer’s Disease Center (RADC) which were linked to Medicare claims data of ICU admissions between 1991 and 2018. Participants were 3,822 older adults (mean age 77.3 years, 26 percent male) without dementia at baseline. Of these, 52.1 percent (n=1,992) had been admitted to the ICU, of whom 27.0 and 25.1 percent were admitted before enrolment and during follow-up, respectively.

Standardized annual cognitive assessment was utilized to identify incident Alzheimer’s and all-type dementia. The participants were followed up for a mean 7.8 years, during which time 23 and 24 percent developed Alzheimer’s dementia and all-type dementia, respectively.

Admission to the ICU was tied to a twofold risk of developing Alzheimer’s dementia (adjusted** hazard ratio [adjHR], 2.10, 95 percent confidence interval [CI], 1.66–2.65). ICU admission was also associated with a twofold risk of developing all types of dementia (adjHR, 2.20, 95 percent CI, 1.75–2.77). [AAIC 2022, abstract 67719]

“Critical illness and ICU hospitalizations are associated with an increased risk of cognitive impairment in older patients,” said James and co-authors. However, the source of this information is mostly from patients recruited from the ICU and there is little information on their pre-ICU cognitive status, he continued.

“[The findings from the present study] could be significant given the high rate of ICU hospitalization in older persons, and especially due to the tremendous upsurge in ICU hospitalizations during the COVID-19 pandemic,” he pointed out.

“Understanding the link between ICU hospitalization and the development of dementia is of utmost importance now more than ever,” he added. James called for further research into replicating these findings as well as identifying factors that could increase the risk for dementia including if there are “potentially modifiable procedures during hospitalization that drive dementia risk.”