Using linear regression analysis with fixed effects we found that LOS (p < 0.001) and postoperative administration of RBC units (p < 0.001) were predictors for delayed mobility but not gender, age, preoperative Hb level, severity of anaemia, CRP level, ASA, preoperative Hb increase, and intraoperative administration of RBC units (Supplemental Fig. 10). The gene discussed is GSTM1; the disease is anemia.