Pharmacologic prophylaxis of postoperative delirium in elderly patients: A network meta-analysis of randomized controlled trials

Background: The high incidence and mortality rates of postoperative delirium (POD) among elderly patients highlights the pressing need for tailored prophylactic strategies. Despite various pharmacologic prophylactic strategies have been reported effective, their overall benefit and safety remain unclear in the geriatric population. Our network meta-analysis (NMA) aimed to systematically evaluate and rank the effectiveness of various pharmacological interventions in preventing POD in elderly patients. Methods: We conducted an extensive search of PubMed, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, and Google Scholar for randomized controlled trials (RCTs) published up to August 1, 2023. We included RCTs examining pharmacological prophylactic effects of POD in elderly patients. To extract data in alignment with predefined areas of interest, we employed the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The primary outcome was the incidence of POD. For secondary outcomes, we evaluated tolerability through all-cause discontinuation or drop-out rates, as well as all-cause mortality. Results: Our analysis encompassed a total of 44 RCTs involving 11,178 patients. Out of these, 26 RCTs involved comparisons with placebo only. For delirium prevention, the treatment groups receiving atypical antipsychotics (odds ratio (OR) of 0.27 and 95% confidence interval (CI) of 0.12-0.58), haloperidol (OR of 0.42; 95% CI of 0.25-0.71), dexmedetomidine (OR of 0.51 and 95% CI of 0.37-0.71 and melatonergic agents (MMA) (OR of 0.57 and 95% CI of 0.33-0.98) had significantly lower rates of delirium compared to the placebo group. Notably, the atypical antipsychotics ranked as the most effective treatment. For tolerability, no statistically differences in rates of dropout discontinuation and all-cause mortality among groups allocated to the placebo or individual pharmacological treatments. Conclusions: Based on indirect evidence, our network meta-analysis identified atypical antipsychotics, dexmedetomidine, MMA, and haloperidol as effective in preventing POD in the elderly, with atypical antipsychotics ranking highest. However, it is essential to note that these findings should be confirmed through further RCTs.