We found that in the group with normal Hb levels, a BMI of < 18.5 (P < 0.05), T3 or T4 stage (P < 0.05), ASA grade (P < 0.05), free flap (P < 0.05), and bone flap (P < 0.05) were independent risk factors for perioperative transfusion; in the mild anemia group with Hb levels > 90 g/L, our analysis suggested that T3 or T4 (P < 0.05), ASA III or IV (P < 0.05) were independent risk factors for perioperative transfusion. Here, GSTM1 is linked to anemia (phenotype).