Hb levels reported for some patients were very low (two patients had Hb < 4 g/dL and 11 had Hb in the range 4.0 to 4.8 g/dL); these might have resulted from health issues, such as blood loss, unrelated to CKD, but some might have resulted from transcription errors in recording Hb levels in the PRF. Here, GSTM1 is linked to chronic kidney disease.