A new study has revealed a significant link between delirium and dementia. Delirium is a serious change in mental abilities that results in confused thinking and a lack of awareness of someone’s surroundings. Meanwhile, when a person develops dementia, it impairs a person’s ability to remember, think, or make decisions that interfere with everyday activities.
The retrospective study was conducted in collaboration with researchers from the Australian Institute of Health Innovation (AIHI) at Macquarie University and the University of Queensland (UQ). During this study, the researchers analysed anonymized hospital records for more than 110,000 people aged over 65 in New South Wales over 11 years, revealing a significant link between delirium and dementia.
The study published in the latest edition of the British Medical Journal shows that patients who had at least one episode of delirium while in the hospital went on to develop dementia at triple the rate of patients who had not experienced delirium.
Delirium is a sudden change in a person’s mental state and is characterised by disorientation and confusion. It is common in older people during hospitalisation. Previous research has shown it affects more than 40 per cent of people aged 80 and older.
To reach these findings, the research team examined an immense dataset containing millions of public and private hospital records for patients aged 65 and older between 2001 and 2020, before narrowing the date range.
From this, patients were identified who had experienced at least one episode of delirium during hospitalisation. Each was paired with a ‘twin’ who shared characteristics such as age and sex but who had not experienced delirium, giving researchers 55,211 pairs to follow over five years.
The delirium cohort was diagnosed with dementia at three times the rate of the non‑delirium cohort, with each additional episode of delirium associated with a 20 per cent increase in the risk of dementia.
Additionally, the delirium cohort were 39 per cent more likely to die in the period under review.
According to statement from the University, the work arose from a study on frailty being run by the NHMRC Partnership Centre for Health System Sustainability led by AIHI Founding Director, Professor Jeffrey Braithwaite.
Rather than being an inevitable part of aging, frailty has been identified as a medical condition resulting in poorer physical and cognitive reserves and a poorer quality of life.
Professor of Medical AI, Shlomo Berkovsky, led the Macquarie University team who analysed the enormous dataset.
“We requested this information from NSW Health to look at the causes of frailty in elderly people. All elderly patients who are admitted to hospital are assessed for frailty and receive a frailty score. This indicates whether they can safely undergo treatments such as heart surgery, but it doesn’t specify exactly what aspect of their health is contributing to their poor physical condition. As we analysed the data, we could see different clusters appearing, including dementia. The University of Queensland clinician researchers were already looking at potential links between delirium and dementia, and they were able to develop the critical question we needed to direct our analysis,” ,” Professor Berkovsky said in a statement.
The researcher also said that these results don’t prove categorically that delirium leads to dementia, but we have found a strong causal relationship between the two, which is a very large smoking gun.
Dr Emily Gordon, UQ Centre for Health Systems Research Fellow, and the paper’s lead author, says the findings of the study have major implications for clinical practice.
“We know that delirium is common and dangerous. We also know about 40 per cent of delirium cases are preventable, with readily available interventions such as keeping hydrated, well nourished and mobile. So it follows that delirium prevention and treatment are likely to be unrivalled opportunities to reduce the burden of dementia globally,” she said.