GSTM1 and acute kidney injury: Preoperatively, the AKI group had a significantly lower preoperative Hb (P <  0.001), BUN (P <  0.001), preoperative (P = 0.034) and postoperative creatinine (P <  0.001), eGFR (P <  0.001), proteinuria (P = 0.029), ESR (P <  0.001), and CRP (P = 0.012) levels.