GSTM1 and chronic kidney disease: In the non-dialysis population, the REPAIR-IDA study – an RCT in 2584 ND-CKD patients – showed that higher doses of IV iron (1500 mg ferric carboxymaltose) resulted in greater increases in haemoglobin (Hb) and iron parameters compared to lower doses (1000 mg iron sucrose), with similar safety observations reported between the two groups [13].