A recent meta-analysis reported that there was no association between APOE and delirium, although the number of delirium cases included was smaller than in the present study.28 Here, we showed carriers of an APOE ε4 allele were at an increased risk of delirium independent of a dementia diagnosis in our analyses, suggesting that APOE may constitute a shared mechanism between the 2 conditions. Here, APOE is linked to delirium.