TAC1 and delirium: The baseline LDL levels of the “no postoperative delirium group” (2.4 ± 0.3 mmol/L) and the “postoperative delirium group” (2.5 ± 0.2 mmol/L) were significantly statistically different (p = 0.028), while after surgery, the postoperative substance P levels of the “no postoperative delirium group” (31.9 ± 4.7 mmol/L) was found to be significantly lower (p < 0.001) than that of the “postoperative delirium group” (46.3 ± 6.1 mmol/L) (Figure 2).