In CKD, predictors of ESA hyporesponsiveness were C-reactive protein (OR = 1.2, 95% CI: 1.0–1.5; P-value = 0.060) and high levels of baseline Hb (OR = 1.7, 95% CI: 1.2–2.2; P-value< 0,001), the latter being also predictor of ESA hyporesponsiveness in cancer (OR = 1.7, 95% CI: 1.1–2.4; P-value = 0.007). This evidence concerns the gene GSTM1 and chronic kidney disease.