Effects of high-dose vitamin B6 therapy on microcytic and hypochromic anemia in hemodialysis patients

In an attempt to treat hemodialysis patients suffering from microscopic and hypochromic anemia (MHA) and who are either sufficient or deficient in serum ferritin level, we investigated the effects of oral administration of vitamin B6 (VB6). Twenty-six patients with MHA undergoing long-term stable hemodialysis treatment were divided into three groups. There was no significant difference in the serum VB6 levels in these patients as compared with normal subjects before the study. Patients in group I, whose serum ferritin levels were normal, were orally administered 180mg of VB6 every day for 20 weeks. Patients in groups II and III, whose serum ferritin levels were far below normal (due to suspected iron deficiency anemia), were either administered iron alone (intravenous administrationof 40mg of iron for 12 consecutive dialysis treatments, for 4 weeks - group II) or both iron and VB6 (group III). There was significant improvement in the hematocrit, mean corpsular volume (MCV), and mean corpsular hemoglobin (MCH) in group I patients supporting the contention that this group of patients had pyridoxine responsive anemia (PRA). The number of sideroblasts in bone marrow in these patients, however, was significantly low when compared to that of the normal subjects. In addition, the combined therapy with iron and VB6 led to the longer-sustained improvement in hematocrit in patients with suspected iron deficiency anemia (group III) when compared to those treated with iron alone (group II). These data suggest that VB6 is useful in hemodialysis patients with MHA with either a sufficient or deficient serum ferritin level, and that the mechanisms of MHA in hemodialysis patients should be further investigated in relation to iron and VB6 metabolism.