In the logistic regression models, SOD1 activity higher than 3.32 U/mg Hb was associated with protection of AKI development when adjusted by hemoglobin, phosphorus and APACHE II score (OR 0.309; CI 95 % 0.137–0.695; p = 0.005) and when adjusted by age, gender, CKD, admission category (medical or surgery) and APACHE II (OR 0.129; CI 95 % 0.033–0.508; p = 0.003; Table 4). The gene discussed is GSTM1; the disease is chronic kidney disease.