Taking group 1 as the control group, the univariate Cox regression showed that Hb and HCT trajectory groups 2 to 4 had potential protective effects against the composite outcome in patients with CKD stages 3–4 [Hb: group 2 HR (95% CI): 0.429 (0.321, 0.573), p = 0.000; group 3 HR (95% CI): 0.184 (0.130, 0.261), p<0.000; group 4 HR (95% CI): 0.075 (0.040, 0.142), p = 0. The gene discussed is GSTM1; the disease is chronic kidney disease.