Age, BMI, operation time, intraoperative blood loss, history of hypertension, history of stroke, history of osteoporosis, TP, ALB, SAA, RBC, Hb, HCT, and MCHC were found to be associated with postoperative anemia, while sex, diabetes, and TP did not show similar effects. The gene discussed is GSTM1; the disease is anemia (phenotype).