A meta-analysis on the factors of postoperative delirium in patients undergoing routine care in the recovery room

Objective To systematically evaluate the risk factors associated with postoperative delirium (POD) in patients receiving routine care in the post-anesthesia care unit (PACU). Methods Relevant literature concerning risk factors for POD in PACU patients was retrieved from CNKI, Wanfang, and VIP databases from inception up to August 2025. Three researchers independently completed literature screening, data extraction, quality evaluation, and evidence grading. Meta-analysis was performed using RevMan 5.3 software, and publication bias was assessed using Begg's test in Stata 18.0. Results A total of 20 case-control studies involving 6,877 patients were included. Meta-analysis showed that risk factors for POD in PACU patients included: gender (OR = 1.17, 95%CI:1.03–1.33, P = 0.02), age (SMD = 2.05, 95%CI:1.52–2.57, P < 0.00001), prolonged operation time (SMD = 1.02, 95%CI:0.44–1.60, P = 0.0006), low BMI (SMD = −0.29, 95%CI:−0.53–0.04, P = 0.02), prolonged anesthesia time (SMD = 1.58, 95%CI:0.88–2.88, P < 0.00001), hypertension (OR = 1.27, 95%CI:1.06–1.51, P = 0.009), diabetes mellitus (OR = 1.44, 95%CI:1.01–2.06, P = 0.04), smoking (OR = 1.38, 95%CI:1.11–1.71, P = 0.004), decreased hemoglobin level (SMD = −1.05, 95%CI: −3.97–0.12, P = 0.04), alcohol consumption (OR = 1.33, 95%CI:1.05–1.63, P = 0.02), increased intraoperative blood loss (SMD = 3.74, 95%CI:1.60–5.87, P = 0.0006), higher American Society of Anesthesiologists (ASA) physical status classification (OR = 0.66, 95%CI:0.47–0.92, P = 0.02), insufficient use of dexmedetomidine (OR = 0.33, 95%CI:0.23–0.52, P < 0.00001), prolonged hospital stay (SMD = 2.01, 95%CI:0.76–3.27, P = 0.002), low educational level (OR = 1.43, 95%CI:1.03–1.98, P = 0.03), history of cerebral infarction (OR = 2.31, 95%CI:1.48–3.60, P = 0.0002), and decreased postoperative albumin level (SMD = −1.91, 95%CI: −2.76–1.07, P < 0.00001). Conclusion Multiple demographic, perioperative, and disease-related factors are associated with the occurrence of POD in PACU patients under routine care. This study provides an evidence-based reference for the early identification and prevention of POD. The clinical value of these risk factors as an intervention still needs to be verified by high-quality prospective studies. Systematic trial registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420261341102 , identifier: CRD420261341102