Could Delirium be a strong factor for dementia? - Video

Delirium is a sudden change in a person’s usual mental state. Symptoms include agitation, confusion or being unable to stay focused when awake. Delirium is much more common in hospital patients and older people. Previous observational studies have suggested an association between delirium and subsequent dementia, but the relationship remains unclear.

For the study, researchers in Australia analysed data from 626,467 patients aged 65 years and older with no dementia diagnosis who were admitted to hospitals between January 2009 and December 2014. Of these patients, 55,211 had at least one recorded episode of delirium and were matched to another 55,211 patients without delirium by age, sex, frailty, reason for being in hospital, length of stay in hospital and length of stay in the intensive care unit. These 110,422 patients (average age 83) were then followed up for five years to see how many of them were diagnosed with dementia. Collectively, 58% of patients died and 17% had a newly reported dementia diagnosis over the follow-up period.

The results revealed that patients with delirium had a 39% higher risk of death and three times the risk of being diagnosed with dementia than patients without delirium. The relationship between delirium and dementia was stronger in men than women and each additional episode of delirium was associated with a 20% increased risk of developing dementia (a dose-response relationship).

The researchers discovered that among hospital patients with at least one episode of delirium, the risk of receiving a new dementia diagnosis was three times higher than for patients without delirium and each additional episode of delirium increased that risk by 20%.

“While our results are consistent with the hypothesis that delirium plays a causative part in dementia, they are not conclusive owing to the fundamental limitations of observational studies in determining causality. Nevertheless, the results of this study provide valuable insights because prospective randomised controlled trials are unlikely to be conducted,” concluded the researchers.

Reference: Emily H Gordon, senior lecturer, David D Ward, research fellow, Hao Xiong, research fellow, Shlomo Berkovsky, professor of medical artificial intelligence, Ruth E Hubbard, professor of geriatric medicine; Delirium and incident dementia in hospital patients in New South Wales, Australia: retrospective cohort study; Journal: The BMJ; DOI: 10.1136/bmj-2023-077634