The proportion of macrocytic anaemia only slightly rises as Hb falls in CKD: 6.0% (n = 280) of people with Hb ≤ 11 g/dl rising to 7.6% (n = 42) of people with Hb ≤ 9 g/dl (Table 2). This evidence concerns the gene GSTM1 and macrocytic anemia.