Alasdair MacLullich

Programmes and findings

Delirium and geriatric medicine research

My research addresses the recognition, assessment and consequences of delirium, and how clinical care can better support recovery in later life.

Areas of research

Delirium recognition and assessment

Developing and evaluating practical ways to recognise delirium, including the 4AT, and studying attention and cognitive change during acute illness.

Delirium, dementia and mortality

Understanding the links between delirium, prior cognition, long-term cognitive impairment, dementia and mortality.

Implementation and care

Studying how assessment, multidisciplinary care and rehabilitation can improve care during and after an episode of delirium.

Acute geriatrics and hip fracture

Researching acute geriatric and orthogeriatric care, including delirium around hip fracture and inflammatory, stress-response and cognitive mechanisms in acute illness.

Current programmes

I lead or contribute to research on acute illness, long-term cognitive decline and recovery after delirium. This includes the RecoverED programme and work with the Edinburgh Delirium Research Group. Research Explorer lists current projects and outputs.

For research or collaboration enquiries, email a.maclullich@ed.ac.uk.

For fuller publication lists and researcher profiles, see Research Explorer, ORCID, Google Scholar, PubMed, Scopus or ResearchGate.

Findings in brief

  • In a 2026 population-based cohort of 23,558 people aged 65 or over without pre-existing dementia, 4,135 (17.6%) had delirium recorded on admission. Delirium was associated with incident dementia, with the largest relative association among people with 0–1 long-term conditions (adjusted subdistribution hazard ratio 3.38, 95% CI 2.46–4.63).
  • In a 2025 analysis of 75,221 emergency admissions, 62,188 had a 4AT recorded. A score of 1 or more had sensitivity 0.87 (95% CI 0.86–0.87) and specificity 0.71 (0.70–0.71) in relation to a recorded clinical diagnosis of dementia.
  • In a 2025 national Scottish registry study of 18,040 people presenting with hip fracture, 16,476 (91%) received a 4AT. Of those assessed, 3,386 (21%) scored 4 or more, suggestive of delirium; this was associated with higher odds of inpatient mortality (adjusted odds ratio 2.26, 95% CI 1.79–2.84).
  • A 2021 systematic review and meta-analysis of 17 studies, comprising 3,702 observations, estimated pooled 4AT sensitivity of 0.88 (95% CI 0.80–0.93) and specificity of 0.88 (0.82–0.92) for delirium detection.
  • A 2019 multicentre study included 785 analysable acute medical patients aged 70 or over. Each received an independent reference assessment and was randomised to assessment with either the 4AT or CAM. Sensitivity and specificity were 76% and 94% for the 4AT, and 40% and 100% for the CAM.

Earlier selected publications

  1. Bellelli G and colleagues. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people. 2014. Age and Ageing.

  2. Shenkin SD and colleagues. Delirium detection in older acute medical inpatients: a multicentre prospective comparative diagnostic test accuracy study of the 4AT and the confusion assessment method. 2019. BMC Medicine.

  3. Tieges Z and colleagues. Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis. 2021. Age and Ageing.

  4. Davis DHJ and colleagues. Delirium is a strong risk factor for dementia in the oldest-old: a population-based cohort study. 2012. Brain.

  5. MacLullich AMJ and colleagues. Unravelling the pathophysiology of delirium: a focus on the role of aberrant stress responses. 2008. Journal of Psychosomatic Research.

Recent selected publications

  1. Penfold RS, MacRae C, Sampson EL, Davis DHJ, Anand A, Ely EW, Guthrie B, MacLullich AMJ. Delirium, long-term conditions, and incident dementia in older adults admitted to hospital for emergency care in Lothian, Scotland: a population-based cohort study. 2026. The Lancet Healthy Longevity.

  2. Penfold RS, Wilkinson T, Stirland LE, MacRae C, Russ TC, Shenkin SD, Vardy E, Anand A, Guthrie B, Sampson EL, MacLullich AMJ. Prevalence and outcomes of recorded dementia vary by data source: a population cohort study of 133,407 older adults. 2026. Age and Ageing.

  3. Sandeman DVE, Rodgers S, Tocher J, MacLullich AMJ. Delirium after cardiac surgery incidence and perioperative risk factors in a prospective cohort. 2026. Journal of Cardiothoracic Surgery.

  4. Penfold RS, Bowman E, Vardy ERLC, Sampson EL, Anand A, Guthrie B, MacLullich AMJ. Using scores from the 4AT delirium detection tool as an indicator of possible dementia: a study of 75,221 older adult hospital admissions. 2025. Age and Ageing.

  5. Penfold RS, Farrow L, Hall AJ, Clement ND, Ward K, Donaldson L, Johansen A, Duckworth AD, Anand A, Hall DE, Guthrie B, MacLullich AMJ. Delirium on presentation with a hip fracture is associated with adverse outcomes: a multicentre observational study of 18,040 patients using national clinical registry data. 2025. The Bone & Joint Journal.

  6. Penfold RS, Squires C, Angus A, Shenkin SD, Ibitoye T, Tieges Z, Neufeld KJ, Avelino-Silva TJ, Davis D, Anand A, Duckworth AD, Guthrie B, MacLullich AMJ. Delirium detection tools show varying completion rates and positive score rates when used at scale in routine practice in general hospital settings: a systematic review. 2024. Journal of the American Geriatrics Society.

  7. Arnold E, Finucane AM, Taylor S, Spiller JA, O’Rourke S, Spenceley J, Carduff E, Tieges Z, MacLullich AMJ. The 4AT, a rapid delirium detection tool for use in hospice inpatient units: findings from a validation study. 2024. Palliative Medicine.

  8. Penfold RS, Hall AJ, Anand A, Clement ND, Duckworth AD, MacLullich AMJ. Delirium in hip fracture patients admitted from home during the COVID-19 pandemic is associated with higher mortality, longer total length of stay, need for post-acute inpatient rehabilitation, and readmission to acute services. 2023. Bone & Joint Open.

  9. MacLullich AMJ, Hosie A, Tieges Z, Davis DHJ. Three key areas in progressing delirium practice and knowledge: recognition and relief of distress, new directions in delirium epidemiology and developing better research assessments. 2022. Age and Ageing.

  10. Wilson JE, Mart MF, Cunningham C, Shehabi Y, Girard TD, MacLullich AMJ, Slooter AJC, Ely EW. Delirium. 2020. Nature Reviews Disease Primers.

Research links and publication selection reviewed 4 September 2026.