This result is consistent with other studies focusing on preoperative anemia (or Hb) and hip fracture outcomes.13,32–34 Additionally, some other investigators also failed to find an association between postoperative anemia and mortality, while others suggested that postoperation anemia might be a risk factor for complications, readmission, and length of hospital stay.4,12,35,36. This evidence concerns the gene GSTM1 and anemia (phenotype).