The role of opioid analgesics in the development of post-operative delirium: A systematic review and meta-analysis

OBJECTIVE: To determine the influence of various opioid analgesics on the incidence of post-operative delirium (POD) by analyzing all available, relevant -literature. DESIGN: A database search containing keywords assessing opioids and POD was performed in Embase, Web of Science, and MEDLINE-PubMed. Retrieved studies were screened via Rayyan, and adjusted odds ratios (ORs) for associations between opioid analgesia and POD were extracted, with two-sided p-values < 0.05 being deemed significant. RESULTS: A total of 7,700 patients were analyzed, of which 1,703 developed POD, indicating an incidence of 22.1 percent. Random effects meta-analysis based on 95 percent confidence intervals reveals that opioid use (OR 1.15, 1.09-1.22, p < 0.001), specifically with meperidine (OR 3.36, 1.36-8.32, p < 0.009) or morphine (OR 1.42, 1.29-1.57, p < 0.001), is associated with increased incidence of POD. Furthermore, both perioperative (OR 1.10, 1.04-1.16, p < 0.001) and post-operative opioid administration (OR 1.92, 1.25-2.95, p < 0.003) were also associated with increased risk of POD. CONCLUSION: Opioid analgesics were associated with higher incidences of POD. Not all opioids increased the incidence of delirium. Elderly and renally impaired patient populations were at higher risk for developing opioid-related POD. Careful selection and judicious utilization of opioid analgesics may reduce the incidence of POD and ultimately the burden on the healthcare system.