Dexmedetomidine in the prevention of postoperative delirium in elderly patients following non‐cardiac surgery: A systematic review and meta‐analysis

The efficacy of dexmedetomidine in the prevention of postoperative delirium (POD) remains ambiguous, however, it has been used to reduce the incidence of delirium in elderly patients. Here, we conducted a meta-analysis study for assessing the effects of dexmedetomidine on POD among elderly patients following non-cardiac surgery. A systematic literature search was performed against the PubMed, EMBASE, Cochrane Library, and Web of Science databases, and all relevant literature published till November 30, 2019, were considered. Our analysis included 16 randomised controlled trials conducted with 4534 patients for exploring the effects of dexmedetomidine on POD in elderly patients following non-cardiac surgery. It was observed that the overall incidence of POD was significantly lower in the dexmedetomidine group than in the control group (risk ratio [RR] 0.51, 95% confidence interval [CI] 0.43-0.61, P < .01). Similar results were obtained from subgroup analysis upon comparison of the placebo (RR 0.52, 95% CI 0.41-0.66, P < .01, moderate quality of evidence), propofol-treated (RR 0.55, 95% CI 0.38-0.78, P < .01, low quality of evidence), and midazolam-treated (RR 0.38, 95% CI 0.20-0.71, P < .01, low quality of evidence) groups. Trial sequential analysis revealed that the cumulative z-value superseded the monitoring boundary and reached the required information size. However, patients who received dexmedetomidine had a higher incidence of bradycardia and hypotension. In conclusion, the meta-analysis revealed that dexmedetomidine appears to decrease the risk of POD in elderly patients following non-cardiac surgery. However, as some of the studies were heterogeneous and of low quality, high-quality trials are necessary for drawing more definitive conclusions.