Abstract: Objective To investigate whether apolipoprotein E (APOE) genotypes associate with postoperative delirium in aged noncardiac surgical patients. Methods 212 inpatients, aged 65yr or older, undergoing selective noncardiac surgeries were enrolled in the study. The patients were frequently interviewed and evaluated prospectively for delirium with the Confusion Assessment Method (CAM) during the first three postoperative days. APOE genotype was determined using multiplex amplification refractory mutation system polymerase chain reaction(multi-ARMS PCR) technique. Results Delirium occurred in 45 patients during the first three postoperative days. Of the 212 patients, 18 (8.5%) possessed one or two APOE ε4 allele. There was no significant difference between delirious patients and non-delirious patients(6.7%: 9.0%, P>0.05) in the presence of APOE ε4 allele. In all four APOE ε4/4 homozygote patients, one female patient presented a transient delirium status at three days before surgery, another male patient presented serious fluctuated delirium symptoms from the second to 17th days postoperatively. Conclusion The presence of APOE ε4 allele may not be a predictator of postoperative delirium. APOE ε4/4 homozygote patients may be more indulgent to delirium than others.

Key words: apolipoprotein E, polymorphism, delirium, aging, surgery