Retrospective Cohort Study: Delirium associated with increased risk of subsequent dementia and higher mortality in older adults

Study Design and Population:

This retrospective cohort study utilized hospital administrative data from both public and private hospitals in New South Wales, Australia, spanning from July 2001 to March 2020. The study examined data from 650,590 patients aged 65 years or older, who did not have dementia at baseline. Diagnoses of dementia and delirium were identified using ICD-10 codes. The cohort was carefully matched into 55,211 pairs based on personal and clinical characteristics, focusing on those who developed delirium and their outcomes over a follow-up period exceeding five years.

Main Findings:

The analysis found that patients who experienced delirium had a 39% increased risk of mortality (hazard ratio: 1.39, 95% CI: 1.37-1.41) and a threefold increase in the risk of developing dementia (subdistribution hazard ratio: 3.00, 95% CI: 2.91-3.10) compared to those without delirium. The risk associated with dementia was notably stronger among men. Furthermore, each additional episode of delirium was linked to a 20% increased risk of subsequent dementia (subdistribution hazard ratio: 1.20, 95% CI: 1.18-1.23).

Implications for Practice:

The strong association between delirium and increased risks of death and incident dementia in older adults highlights the importance of delirium as a clinical marker that warrants significant attention. These findings suggest that enhanced monitoring and management of delirium in hospital settings could be crucial for identifying patients at higher risk of adverse outcomes, including dementia. Efforts to improve delirium management might not only address immediate clinical needs but also assist in stratifying risk and tailoring post-discharge care plans to better support the long-term health of these patients. Further research is needed to explore effective strategies for delirium intervention and to determine how these approaches can impact long-term cognitive outcomes and overall mortality.

Reference (free full-text):

Reference: Gordon, E. H., Ward, D. D., Xiong, H., Berkovsky, S., & Hubbard, R. E. (2024). Delirium Associated with Increased Risk of Death and Incident Dementia in Older Adults. BMJ, 384, e077634. DOI: https://doi.org/10.1136/bmj-2023-077634.