Article Text

Original research
Delirium and the risk of developing dementia: a cohort study of 12 949 patients
  1. Samuel P Leighton1,
  2. James W Herron1,
  3. Eric Jackson2,
  4. Matthew Sheridan2,
  5. Fani Deligianni3,
  6. Jonathan Cavanagh4
  1. 1 University of Glasgow, Institute of Health and Wellbeing, Glasgow, Glasgow, UK
  2. 2 Imaging Centre of Excellence, Queen Elizabeth University Hospital, NHS Greater Glasgow and Clyde, Glasgow, UK
  3. 3 University of Glasgow, School of Computing Science, Glasgow, UK
  4. 4 University of Glasgow, Institute of Infection Immunity and Inflammation, Glasgow, UK
  1. Correspondence to Dr Samuel P Leighton, University of Glasgow Institute of Health and Wellbeing, Glasgow G12 8RZ, UK; samuel.leighton{at}


Background Delirium is an important risk factor for subsequent dementia. However, the field lacks large studies with long-term follow-up of delirium in subjects initially free of dementia to clearly establish clinical trajectories.

Methods We undertook a retrospective cohort study of all patients over the age of 65 diagnosed with an episode of delirium who were initially dementia free at onset of delirium within National Health Service Greater Glasgow & Clyde between 1996 and 2020 using the Safe Haven database. We estimated the cumulative incidence of dementia accounting for the competing risk of death without a dementia diagnosis. We modelled the effects of age at delirium diagnosis, sex and socioeconomic deprivation on the cause-specific hazard of dementia via cox regression.

Results 12 949 patients with an incident episode of delirium were included and followed up for an average of 741 days. The estimated cumulative incidence of dementia was 31% by 5 years. The estimated cumulative incidence of the competing risk of death without dementia was 49.2% by 5 years. The cause-specific hazard of dementia was increased with higher levels of deprivation and also with advancing age from 65, plateauing and decreasing from age 90. There did not appear to be a relationship with sex.

Conclusions Our study reinforces the link between delirium and future dementia in a large cohort of patients. It highlights the importance of early recognition of delirium and prevention where possible.


Data availability statement

Data may be obtained from a third party and are not publicly available. The study data is available by application to West of Scotland Safe Haven.

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See:

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Data availability statement

Data may be obtained from a third party and are not publicly available. The study data is available by application to West of Scotland Safe Haven.

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  • Twitter @samleighton87, @mattdoc1982

  • Contributors SPL, JWH, EJ, MS and JC formulated the research question and designed the study. SPL analysed the data. SPL and JWH drafted the manuscript. EJ, MS, FD and JC critically evaluated and revised the manuscript. SPL serves as guarantor for the study.

  • Funding SPL is funded by a Clinical Academic Fellowship from the Chief Scientist Office, Scotland (CAF/19/04). JC is supported by funding from the Medical Research Council (MR/S035753/1), the Wellcome Trust (104025/Z/14/Z), Versus Arthritis (22453) and the Inger and George M Simpson Donation.

  • Competing interests EJ has received honorariums from Biogen and General Electric Healthcare. MS has received an honorarium from General Electric Healthcare. JC attended a Glasgow masterclass in dermatology funded by Janssen.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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