A previous study found that patientswith mild anaemia receiving peri-operative transfusion had significantly higherodds of mortality and in-hospital complications (ORs of 5.7 and 4.3,respectively) than those who did not receive transfusion (mild anaemia wasdefined as a Hb level of 100–120 g/L in women and 100–130 g/L in men) [28]. The gene discussed is GSTM1; the disease is anemia.