Moreover, we chose homocysteine and CRP, but not other inflammatory factors, e.g., S100β and interleukin 6, in the present study because we aimed to use preoperative homocysteine and postoperative CRP to specifically investigate the effects of interaction between the predisposing factor (preoperative homocysteine) and the precipitating factor (postoperative CRP) on the postoperative delirium. The gene discussed is CRP; the disease is delirium.