Statistical analysis

Review Manager45 was used to present the data from all studies graphically, to perform a meta-analysis when possible and to perform and standardize the risk of bias assessment.

Meta–analysis was performed when two or more articles presented results for the same comparison and similar intervention techniques to prevent delirium (clinically homogeneous groups). Pooled risk ratio (RR) with a 95% confidence interval (CI) was calculated for the incidence of delirium (dichotomous outcome) using random–effects methods. The Mantel-Haenszel test was used. Studies in the pooled analyses were tested for heterogeneity using inconsistency I², where a cut-off of 60% was considered methodically relevant.

The p-values that are presented in this review are the ones calculated for between-group differences as presented by the authors in the original studies. A p-value of <0.05 (two-tailed) was considered statistically significant.

This manuscript was reported using the checklist provided in the PRISMA Statement.46