Edmonton frailty scale score predicts postoperative delirium: a retrospective cohort analysis

Abstract

Abstract Background Frailty has been associated with postoperative delirium (POD). Studies suggest that the Fried phenotype has a stronger association with POD than the Edmonton Frailty Scale (EFS) criteria. Although phenotypic frailty is recognized as a good predictor of delirium, the EFS has higher ratings for feasibility in the surgical setting. Thus, our aim was to determine the association between EFS-assessed vulnerability and POD in an elective surgical population of older adults. A secondary aim was to determine which domains assessed by the EFS were closely associated with POD. Methods After IRB approval was received, electronic medical records of surgical patients at our institution were downloaded from 12/1/2018 to 3/1/2020. Inclusion criteria included age ≥ 65 years, preoperative EFS assessment within 6 months of surgery, elective surgery not scheduled for intensive care unit (ICU) stay but followed by at least 1 day postoperative stay, and at least two in-hospital evaluations with the 4 A’s test (arousal, attention, abbreviated mental test-4, acute change [4AT]) on the surgical ward. Vulnerability was determined by EFS score ≥ 6. Patients were stratified into two groups according to highest postoperative 4AT score: 0–3 (no POD) and ≥ 4 (POD). Odds of POD associated with EFS score ≥ 6 were evaluated by using logistic regression adjusted for potential confounders. Results The dataset included 324 patients. Vulnerability was associated with higher incidence of POD (p = 0.0007, Fisher’s exact). EFS ≥6 was consistently associated with POD in all bivariate models. Vulnerability predicted POD in multivariable modeling (OR = 3.5, 95% CI 1.1 to 11.5). Multivariable analysis of EFS domains revealed an overall trend in which higher scores per domain had a higher odds for POD. The strongest association occurred with presence of incontinence (OR = 3.8, 95% CI 1.2 to 11.0). Conclusions EFS criteria for vulnerability predict POD in older, non-ICU patients undergoing elective surgery.