(2) The robustness of this study was tested with a set of sensitivity analyses(target independent variable transformation, subgroup analysis, using a GAM to insert the continuity covariate into the equation as a curve, calculating E-values to explore the potential for unmeasured confounding, and reanalyzing the association between Hb and CKD progression after excluding participants with UPCR ≥ 0.5 g/gCr or eGFR < 15 ml/min per 1.73 m2) to ensure the reliability of the results. The gene discussed is GSTM1; the disease is chronic kidney disease.