GSTM1 and chronic kidney disease: This difference was also evident when comparing the median Hb values of male (13.1 [11.2–14.5] g/dl) and female (11.9 [10.7–12.9] g/dl) patients with CKD with the respective medians of healthy individuals of the same sex (14.8 [14–15.3] g/dl and 13.1 [12.7–13.6] g/dl, respectively, both P < 0.001).