GSTM1 and anemia (phenotype): A retrospective cohort study was conducted in adult patients with stage ≥3a nondialysis-dependent CKD and hemoglobin (Hb) <11 g/dl (January 2013–November 2021; N=26,626) to assess longitudinal treatment patterns, Hb, and iron parameters (ferritin and transferrin saturation) for anemia management.