The Association Between Frailty and Delirium Among Hospitalized Patients: An Updated Meta-Analysis

Objective: The aim of our meta-analysis was to update evidence for the association between frailty and delirium in different types of hospitalized patients, given the large volume of new studies with inconsistent results. Design: Systematic review and meta-analysis. Setting and Participants: In this updated meta-analysis, we searched 3 databases (Embase, PubMed, and the Cochrane Library) for observational studies, exploring the association between frailty and delirium from database inception to September 21, 2020, among hospitalized patients. Relevant data were extracted from the studies that were included. A random effects model was conducted to synthesize and pool the effect size of frailty on delirium due to different frailty score instruments, different countries, and various delirium assessments that were used. The participants enrolled in this meta-analysis were hospitalized patients. Measures: Delirium risk due to frailty. Results: A total of 30 independent studies from 9 countries, consisting of 217,623 patients, was identified, and the prevalence of frailty ranged from 16.20% to 78.00%. Frail patients exhibited an increased risk for delirium compared to those without frailty [odds ratio (OR) 2.96, 95% confidence interval (CI) 2.36-3.71]. In addition, different types of hospitalized patients had various OR values, which were 2.43 for selective surgical patients (95% CI 1.88-3.14), 3.61 for medical patients (95% CI 3.61-7.89), 3.76 for urgent surgical patients (95% CI 2.88-4.92), and 6.66 for emergency or critical illness patients (95% CI 1.41-31.47). Subgroup analysis based on the frailty score instrument showed the association still existed when using the Clinical Frailty Scale (OR 4.07, 95% CI 2.71-6.11), FRAIL Scale (OR 2.83, 95% CI 1.56-5.13), Frailty Index (OR 6.15, 95% CI 3.75-10.07), frailty phenotype (OR 2.30, 95%CI 1.35-5.66), or Erasmus Frailty Score (OR 2.79, 95% CI 1.63-4.77). However, an association between frailty and delirium was not observed when the Edmonton Frail Scale was used (OR 1.45, 95% CI 0.91-2.30). Conclusions and Implications: A 2.96-fold incremental risk of delirium in frail patients underscores the need for early screening of frailty and comprehensive delirium prevention. Appropriate interventions by clinicians should be performed to manage delirium, potentially reducing adverse clinical outcomes for hospitalized patients. (C) 2021 Published by Elsevier Inc. on behalf of AMDA - The Society for Post-Acute and Long-Term Care Medicine.