Compared to the single group, the repeated group exhibited fewer white, longer length of ICU stays, higher scores for SOFA, CCI, and SAPS-II, lower levels of Hb and PLT, and a lower incidence of comorbidities including acute kidney injury, chronic kidney disease, essential hypertension, heart failure, respiratory failure and diabetes mellitus (all P < 0.05). This evidence concerns the gene GSTM1 and chronic kidney disease.