ICU hospitalization and incident dementia in community‐based cohorts of older adults

Abstract

AbstractBackgroundCritical illness and intensive care unit (ICU) hospitalization in older patients have been shown to increase risk of long‐term cognitive impairment. However, most data come from patients recruited from the ICU without controls or information on pre‐ICU cognition. We are not aware of a community‐based sample that allows examination of how ICU hospitalization changes risk for dementia.MethodWe used data from 5 diverse epidemiologic cohorts at the Rush Alzheimer’s Disease Center (RADC) linked to Medicare claims data from 1991 to 2018 to observe ICU hospitalizations (both prior to RADC enrollment and during RADC follow‐up) in older adults enrolled without known dementia. Incident Alzheimer’s and all type dementia was assessed using standardized annual cognitive assessment. The association of ICU hospitalization with incident dementia was tested in a time‐varying Cox model allowing hazard rate to change at time of ICU hospitalization during follow‐up. All models were adjusted for age, sex, education, and race. Fully adjusted models also included terms for baseline measures of hypertension, diabetes, BMI, vascular risk factors, vascular disease burden, other chronic medical conditions, functional disabilities, depression, and physical activity.ResultParticipants (n = 3,822; mean age = 77.3, SD = 7.5) were followed for an average of 7.8 years (SD = 5.5) from study enrollment. ICU hospitalization was experienced by 1,992 (52.1%) of participants; 1031 (27.0%) before RADC enrollment, and 961 (25.1%) during follow‐up. In models adjusted for demographics, ICU hospitalization was associated with an increased risk of Alzheimer’s (HR = 1.63, 95% CI = 1.41, 1.88) and all type dementia (HR = 1.71, 95% CI = 1.48, 1.97). In fully adjusted models, the association was stronger with ICU associated with double the risk of Alzheimer’s (HR = 2.10, 95% CI = 1.66, 2.65) and all type dementia (HR = 2.20, 95% CI = 1.75, 2.77).ConclusionWe found that ICU hospitalization was associated with double the risk of dementia in community‐based older adults compared to those who did not experience ICU hospitalization using standardized annual cognitive assessment. These findings could be significant given the high rate of ICU hospitalization in older persons, and rising ICU hospitalizations more recently during the COVID‐19 pandemic.