The association between the postoperative plasma concentration of CRP and the incidence, duration, and severity of postoperative delirium can be modified by the apolipoprotein E (APOE) 4 genotype (Vasunilashorn et al., 2020) and the catechol-O-methyltransferase (COMT) genotype (Vasunilashorn et al., 2019). This evidence concerns the gene CRP and delirium.