A total of 75 (25.6%) patients experienced POD, and patients with POD were significantly older (82.24 ± 8.57 vs. 79.68 ± 9.88, P < 0.05), had a greater percentage of diabetes (46.7% vs. 32.1%, P < 0.05), had a greater SII [788.39 ± 528.49 vs. 628.86 ± 616.81, P < 0.05], had a greater CRP level (24.58 ± 11.96 vs. 21.29 ± 12.23, P < 0.05), had a lower lymphocyte count (1.27 ± 0.39 vs. 1.41 ± 0.50, P < 0.05) and had a lower total albumin (34.04 ± 4.51 vs. 35.29 ± 3.65, P < 0.05). The gene discussed is CRP; the disease is diabetes mellitus.