Delirium Hub: Research
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This section of the BGS Delirium Hub examines some of the current research and evidence on delirium.
All settings
Systematic reviews
- Patients’ experiences of delirium: A systematic review and meta-summary of qualitative research – Journal of Advanced Nursing (2021)
A systematic review of patients' subjective experiences of delirium showing it to be a distressing condition, the effects of which can persist after discharge from hospital.
Peri-operative medicine
Interest has been shown in prevention of peri-operative delirium. Non-pharmacological methods have been demonstrated to be beneficial. There may be a role for dexmedetomidine in risk reduction for delirium when compared with other forms of sedation, though this does not replace standard risk reduction and treatment methods.
Systematic review & meta-analysis
- Prevention of postoperative delirium in elderly patients planned for elective surgery: systematic review and meta-analysis – Clinical Interventions in Aging (2019)
This is a systematic review of interventions to prevent delirium in older, non-ITU, elective, non-cardiac surgery patients. It showed benefit from various interventions (including pharmacological interventions), but studies were heterogeneous and require further study together with existing methods of delirium prevention.
- Effect of regional versus general anaesthesia on postoperative delirium in elderly patients undergoing surgery for hip fracture: a systematic review – BMJ (2018)
Systematic review showing no difference between regional versus general anaesthesia on rates of delirium in hip fracture patients, but further data required.
Randomised-controlled trials
- Dexmedetomidine versus propofol sedation reduces delirium after cardiac surgery: a randomized controlled trial – Anesthesiology (2016)
Study showing reduced levels of delirium with dexmedetomidine compared with propofol for post-operative sedation in patients who had undergone cardiac surgery.
- Impact of postoperative dexmedetomidine infusion on incidence of delirium in elderly patient undergoing major elective noncardiac surgery: a randomized clinical trial – Drug Design, Development and Therapy (2019)
A RCT which did not demonstrate benefit of dexmedetomidine compared to placebo to reduce delirium within 5 days post-operatively. However, pain and sleep were better in the treatment group.
- Effect of depth of sedation in older patients undergoing hip fracture repair on postoperative delirium. The STRIDE randomized clinical trial - JAMA Surgery (2018)
RCT which compared deep versus light sedation in patients having hip fracture surgery, which did not show a significant difference between either approach.
Observational studies
- Cognitive trajectories after postoperative delirium - NEJM (2012)
Study looking at cognitive outcomes in 12 months after cardiac surgery, showing consistently lower cognitive scores on MMSE in patients who developed delirium over the 12 months post-surgery.
- Postoperative delirium in total knee and hip arthroplasty patients: a study of perioperative modifiable risk factors - British Journal of Anaesthesia (2018)
Observational study showing risk of delirium associated with type of anaesthesia (lower with spinal/epidural), perioperative medications (post-operative benzodiazepines and ketamine infusion were particularly high risk) and medical co-morbidities in patients having TKR and THR.
Reviews
- Perioperative delirium and its relationship to dementia - Progress in Neuro-Psychopharmacology and Biological Psychiatry (2013)
A review which explores the link between peri-operative delirium and subsequent dementia.
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Risk factors for postoperative delirium: An umbrella review of systematic reviews – International Journal of Surgery (2021)
A systematic review which neatly lays out risk factors for delirium across different surgical specialties.
General medicine
Delirium is common among patients cared for by general physicians. It is associated with worse outcomes and extensive work has been carried out to design methods to detect and treat delirium. The search for a pharmacological treatment for delirium has been elusive. Non-pharmacological methods have an established role.
Systematic review & meta-analysis
- Association of delirium with long-term cognitive decline: a meta-analysis – JAMA (2020)
A meta-analysis which demonstrates a significant association between delirium and long-term cognitive decline.
- Risk factors for incident delirium among older people in acute hospital medical units: a systematic review and meta-analysis – Age and Ageing (2020)
Meta-analysis identifying several risk factors for delirium in acute hospital settings.
- Which medications to avoid in people at risk of delirium: a systematic review - Age & Ageing (2011)
Systematic review which concludes by advising to avoid a number of drug classes – in particular benzodiazepines, opiates (being mindful to avoid uncontrolled pain), H1-antagonists and dihydropyridines.
- Non-pharmacological interventions for preventing delirium in hospitalised non-ICU patients – Cochrane Database of Systematic Reviews (2021)
A systematic review of the effectiveness of multimodal non-pharmacological approaches to managing delirium showing positive results for such interventions.
- How do predisposing factors differ between delirium motor subtypes? A systematic review and meta-analysis - Age and Ageing (2022)
Systematic review showing differences in baseline characteristics between patients based on psychomotor subtype.
Randomised-controlled trials
Many RCTs have been carried out to evaluate the effectiveness of various pharmacological therapies to prevent and treat delirium. Results have been mixed, but in general are reserved to treat distressing symptoms of delirium, with the focus remaining on prevention reversing the underlying cause.
Observational studies
- Delirium in an adult acute hospital population: predictors, prevalence and detection – BMJ Open (2013)
A point prevalence study which shows delirium occurs in about 1/5 of adult medical in-patients and over 1/3 of patients aged over 80.
- Observational, longitudinal study of delirium in consecutive unselected acute medical admissions: age-specific rates and associated factors, mortality and re-admission – BMJ Open (2015)
Longitudinal study which showed delirium in acute medical in-patients was associated with increased mortality, institutionalisation and dependency over 2-4 years of follow-up.
- Recurrent delirium over 12 months predicts dementia: results of the Delirium and Cognitive Impact in Dementia (DECIDE) study – Age & Ageing (2021)
Recent study showing that recurrent delirium is associated with increased risk of cognitive decline and new onset of dementia over 12 months.
- The effect of baseline cognition and delirium on long-term cognitive impairment and mortality – The Lancet Healthy Longevity (2022)
Longitudinal study showing high baseline cognition protects against delirium, but delirium is linked to later cognitive decline.
Reviews
- Delirium in hospitalised older adults – NEJM (2017)
Review of delirium in hospitalised older adults
- Delirium in elderly people – Lancet (2014)
Review of delirium in older people.
- The interface between delirium and dementia in elderly adults - Lancet Neurology (2015)
A review which broadly explores the relationship between delirium and dementia.
- The inter-relationship between delirium and dementia: the importance of delirium prevention - Nature Reviews Neurology (2022)
Wide reaching review article which explores complex the relationship between delirium and dementia.
- Current Challenges in the Recognition and Management of Delirium Superimposed on Dementia – Neuropsychiatric Disease and Treatment (2021)
Review article which gives an overview of the challenging clinical scenario of delirium superimposed on dementia
Critical Care
Patients admitted to intensive care units are at very high risk of developing delirium. Care is required to reduce the risk of developing delirium and to pro-actively treat it when present.
General
- Critical Illness, Brain Dysfunction, and Survivorship (CIBS) Center
Comprehensive resource hub on delirium in critical care, including tools, research, and education materials.
Systematic review & meta-analysis
- Outcome of delirium in critically ill patients: a systematic review and meta-analysis – BMJ (2015)
A systematic review of delirium in ITU, indicating that one third of all patients in critical care settings develop delirium and are at higher risk of dying, as well as other complications.
- A systematic review of implementation strategies for assessment, prevention, and management of ICU delirium and their effect on clinical outcomes – Critical Care (2015)
A systematic review looking at implementation of process measures for assessment to improve clinical outcomes in ICU delirium. Results indicated that such strategies may improve clinical outcomes, but prospective confirmation that such measures correlate with outcome data was needed.
- The effect of dexmedetomidine on delirium and agitation in patients in intensive care: systematic review and meta-analysis with trial sequential analysis – Anaesthesia (2018)
A systematic review and meta-analysis of trials comparing dexmedetomidine to placebo to reduce ITU-delirium and agitation, which showed a significant reduction in the dexmedetomidine group. This however, does not replace standard delirium prevention methods and ensuring to focus on reversing the underlying cause.
Reviews
- Delirium in the intensive care unit – Critical Care (2008)
Review article on delirium in the intensive care unit.
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COVID-19: ICU delirium management during SARS-CoV2 pandemic - Critical Care (2020)
A review which discusses the importance of maintaining high standards of care for patients admitted to ICU with COVID-19 who develop delirium.
Delirium screening
Delirium has been under-recognised in medical settings. Extensive work has been carried out to design screening tools to improve the detection of delirium.
- Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis - Age & Ageing (2021).
Meta-analysis showing performance of 4AT in a variety of settings with a sensitivity of 88% and specificity of 88%.
- NIDUS
Network for Investigation of Delirium: Unifying Scientists. A research consortium to help tp consolidate and co-ordinate research into delirium.
- Delirium, neurofilament light chain, and progressive cognitive impairment – The Lancet Healthy Longevity (2023)
A longitudinal study which shows a link between NfL (a marker of brain injury), delirium and subsequent cognitive decline with implications on the pathophysiology of cognitive impairment post-delirium.
