Risk factors associated with delirium in older emergency department patients: A systematic review and meta-analysis
Juan Mu, Liqun ZouBackground:
Delirium is a frequent yet underrecognized neuropsychiatric syndrome among older patients presenting to the emergency department (ED) and is associated with adverse outcomes, including prolonged hospitalization, functional decline, and mortality. Evidence on ED delirium risk factors remains fragmented.
Methods:
We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library from database inception to December 31, 2025. Comparative observational studies of ED patients aged 65 years or older were eligible if delirium was assessed using a validated tool or diagnostic criteria and if a delirium versus non-delirium comparison was available. Studies enrolling only patients with delirium or lacking a non-delirium comparator were excluded from the risk-factor meta-analysis. Adjusted odds ratios (ORs) were preferentially extracted; unadjusted ORs or raw data were used only when adjusted estimates were unavailable. Random-effects models were used for clinically comparable risk-factor domains.
Results:
Sixteen comparative observational studies involving 31,543 older ED patients were included. The pooled delirium prevalence was approximately 10%. Factors significantly associated with delirium included advanced age (OR = 1.49, 95% confidence initerval [CI]: 1.13–1.97), baseline cognitive impairment or dementia (OR = 1.90, 95% CI: 1.31–2.76), and medication-related exposures (OR = 1.49, 95% CI: 1.20–1.85). Functional dependence and ED-related environmental or process factors were not statistically significant in pooled analyses, and comorbidity burden showed a borderline association. Most included studies were of moderate-to-high methodological quality. Heterogeneity was substantial in several domains, and no strong evidence of publication bias was detected for the cognitive impairment analysis.
Conclusion:
In older ED patients, delirium is associated with several demographic and clinical factors, particularly age, baseline cognitive impairment, and medication-related exposures. These associations should be interpreted as risk markers rather than causal effects. Early identification of high-risk patients may support risk stratification and guide future delirium prevention research in the ED.