GSTM1 and anemia: In male group, the percentages of eGFR < 30 ml/min per 1.73m2 (eGFR stages 4 and 5) in different Hb stratification (120-129 g/L, 110-119 g/L, 100-109 g/L, 90-99 g/L, Hb < 90 g/L) were 2.17%, 5.38%,11.36%, 24.00%, 33.34% respectively (Figure 1B), which showed that with the aggravation of anemia, the proportion of lower eGFR gradually increased.