GSTM1 and acute kidney injury: Compared to non-AKI patients, AKI patients had significantly higher maximum intraoperative lactate levels (median of 3.5 vs. 2.5 mmol/L, P < 0.001), lower minimum intraoperative Hb levels (median of 7.0 vs. 7.4 g/dl, P < 0.001), and lower minimum intraoperative Hct levels (median of 22.0% vs. 23.0%, P < 0.001).