Restrictive transfusion strategies (Hb thresholds generally between 7.0 and 8.0 g/dL) were not inferior to liberal strategies (Hb thresholds generally between 9.0 and 10.0 g/dL) in terms of 30-day mortality, but a higher risk of acute coronary syndrome was observed in the restrictive transfusion arm [RR 1.78 95% confidence interval (1.18–2.70)]. Here, GSTM1 is linked to acute coronary syndrome.