Association between frailty and postoperative delirium: a meta-analysis of cohort study

Frailty has been suggested as a possible risk factor for postoperative delirium (POD). However, results of previous studies were not consistent. We performed a meta-analysis of cohort study to evaluate the above association.

Relevant studies were obtained via systematic search of PubMed, Embase, SCOPUS, and Web of Science databases. Only studies with multivariate analysis were included. A random-effect model incorporating the potential heterogeneity was used to combine the results.

Fifteen cohort studies including 3250 adult patients who underwent surgery were included, and the prevalence of frailty was 27.1% (880/3250) before surgeries. Overall, POD occurred in 513 patients (15.8%). Pooled results showed that frailty was associated with a higher risk of POD (adjusted odds ratio [OR]: 3.23, 95% confidence interval [CI]: 2.56-4.07, P < 0.001) without significant heterogeneity (P for Cochrane's Q test = 0.25, I² = 18%). Subgroup analyses showed a more remarkable association between frailty and POD in prospective cohort studies (OR: 3.64, 95% CI: 2.95-4.49, P < 0.001) than that in retrospective cohort studies (OR: 2.32, 95% CI: 1.60-3.35, P < 0.001; P for subgroup difference = 0.04). Moreover, the association was not affected by country of the study, age group of the patient, elective or emergency surgeries, cardiac and non-cardiac surgeries, evaluation instruments for frailty, diagnostic methods for POD, or quality score of the study (P for subgroup difference all > 0.05).

Frailty may be associated with a higher risk of POD in adult population.