Dexmedetomidine (odds ratio 0.46, 95% credible interval 0.36 to 0.57), corticosteroids (0.53, 0.31 to 0.87), melatonin receptor agonists (0.54, 0.34 to 0.85), parecoxib (0.34, 0.16 to 0.74), olanzapine (0.27, 0.07 to 0.94), and intranasal insulin (0.13, 0.04 to 0.34) were the most effective interventions at preventing delirium in trials not at high risk of bias. This evidence concerns the gene INS and delirium.