A randomized controlled trial of oral heme iron polypeptide versus oral iron supplementation for the treatment of anaemia in peritoneal dialysis patients: HEMATOCRIT trial.

Multicentre randomized controlled trial in adult peritoneal dialysis patients with end-stage renal disease who were receiving darbepoetin. Participants were allowed their usual diet, and vitamin B and folic acid supplementation were permitted during the study.

Heme iron polypeptide (Proferrin ES) was given orally as two capsules daily, equivalent to 240 mg elemental iron/day, for 6 months. The comparator was conventional oral iron supplementation with ferrous sulphate.

Heme iron polypeptide did not improve iron repletion, haemoglobin, or darbepoetin requirements versus oral iron, and ferritin levels were lower with heme iron polypeptide. At 6 months by intention-to-treat analysis, transferrin saturation was 22% versus 20% (P = 0.65), ferritin was 124 µg/L versus 292 µg/L (P = 0.003), haemoglobin was 111 g/L versus 113 g/L (P = 0.59), and darbepoetin dose was 20 µg/week versus 20 µg/week (P = 0.66). Adverse events were broadly similar overall (23 vs 24 total adverse events), with more gastrointestinal events in the heme iron polypeptide group, and the overall conclusion was that heme iron polypeptide had no clear safety or efficacy advantage and was unlikely to play a major role in iron supplementation for peritoneal dialysis patients.

The trial was relatively small, with only 32 participants randomized to the heme iron polypeptide arm and fewer analyzed per protocol. Follow-up was limited to 6 months, and the study was not designed to assess long-term clinical outcomes or cost-effectiveness in depth. Several subgroup and safety comparisons were based on small event counts, limiting precision.