Compared with the non‐POD group, elderly patients undergoing hip fracture surgery in the POD group showed statistically significant differences in the following variables (p < .05), including age (≥85), ASA classification (>II), type of anesthesia (general anesthesia), surgery duration (>120 min), perioperative infusion, intraoperative hemoglobin level (Hb < 8 g/dl), perioperative lactic acid measurement (Lac > 2 mmol/L), preoperative pulmonary, cardiovascular diseases, diabetes and drinking history (> 3 times/week), and postoperative VAS scores (Table 1). Here, GSTM1 is linked to diabetes mellitus.