GSTM1 and chronic kidney disease: In light of the controversies previously outlined, our study investigates the relationship between baseline level and longitudinal change of Hb and HCT and CKD prognosis in Chinese patients with CKD stages 3–4 in order to elucidate the intrinsic link between Hb and HCT and CKD short- and long-term prognosis, as well as to determine the optimal range of Hb and HCT control.