Postoperative Delirium in Older Patients: A Systematic Review of Assessment and Incidence of Postoperative Delirium

Postoperative delirium is the most common complication of surgery particularly in older patients.The current study aimed to summarize the commonly used delirium assessment tools in assessing postoperative delirium (POD) and to estimate the incidence rates of POD.A systematic review that included empirical cohort studies reporting the use of delirium assessment tools in assessing POD between 2000 and 2019. Five core databases were searched for eligible studies. The methodological quality assessment of the included studies was undertaken using the Joanna Briggs Institute (JBI) critical appraisal checklist to examine the risk of bias. Pooled incidence estimates were calculated using a random effects model.Nineteen studies with a total of 3,533 postsurgery older patients were included in this review. The confusion assessment method (CAM) and CAM-ICU were the most commonly used tools to assess POD among older postoperative patients. The pooled incidence rate of POD was 24% (95% CI [0.20, 0.29]). The pooled incidence estimates for mixed (noncardiac) surgery, orthopedic surgery, and tumor surgery were 23% (95% CI [0.15, 0.31]), 27% (95% CI [0.20, 0.33]), and 19% (95% CI [0.15, 0.22]), respectively. More than 50% of included studies used CAM to assess POD in different types of postoperative patients. Using CAM to assess delirium is less time-consuming and it was suggested as the most efficient tool for POD detection.We identified that CAM could be implemented in different settings for assessing POD. The incidence and risk factors for POD introduced can be used for future research to target these potential indicators. The incidence rate, risk factors, and predictors of POD explored can provide robust evidence for clinical practitioners in their daily practice.