Fig. 3From: Risk factors of postoperative delirium in the knee and hip replacement patients: a systematic review and meta-analysisForest plots and funnel plot of meta-analysis of advanced age. a Forest plot of SMD of age. b Forest plot of OR of advanced age. c Funnel plot of published studies reporting advanced age as a prognostic factor for POD (Egger’s test p < 0.001)Back to article page