Previous studies have shown a high incidence of POD in elderly patients (≥ 65 years old) with hip fracture and cardiac surgery [8–10], with major risk factors including advanced age, length of nursing home residence, prior cognitive impairment, psychiatric disorders, cerebrovascular disease, end-stage renal failure, low albumin (ALB), high American Society of Anesthesiologists (ASA) classification, and intraoperative blood transfusion [11, 12]. The gene discussed is ALB; the disease is stage 5 chronic kidney disease.