Risk factors and risk stratification approaches for delirium screening: A Geriatric Emergency Department Guidelines 2.0 systematic review

Objective: As part of the Geriatric Emergency Department (ED) Guidelines 2.0 project, we conducted a systematic review to find risk factors or risk stratification approaches that can be used to identify subsets of older adults who may benefit from targeted ED delirium screening.

Methods: An electronic search strategy was developed with a medical librarian, conducted in April 2021 and November 2022. Full-text studies of patients ≥65 years assessed for prevalent delirium in the ED were included. Risk of bias was assessed using the McMaster University Clarity Group tool. Outcomes measures pertained to the risk stratification method used. Due to heterogeneity of patient populations, risk stratification methods, and outcomes, a meta-analysis was not conducted.

Results: Our search yielded 1878 unique citations, of which 13 were included. Six studies developed a novel delirium risk score with or without evaluation of specific risk factors, six studies evaluated specific risk factors only, and one study evaluated an existing nondelirium risk score for association with delirium. The most common risk factor was history of dementia, with odds ratios ranging from 3.3 (95% confidence interval [CI] 1.2-8.9) to 18.33 (95% CI 8.08-43.64). Other risk factors that were consistently associated with increased risk of delirium included older age, use of certain medications (such as antipsychotics, antidepressants, and opioids, among others), and functional impairments. Of the studies that developed novel risk scores, the reported area under the curve ranged from 0.77 to 0.90. Only two studies reported potential impact of the risk stratification tool on screening burden.

Conclusions: There is significant heterogeneity, but results suggest that factors such as dementia, age over 75, and functional impairments should be used to identify older adults who are at highest risk for ED delirium. No studies evaluated implementation of a risk stratification method for delirium screening or evaluated patient-oriented outcomes.