A randomized study of oral vs intravenous iron supplementation in patients with progressive renal insufficiency treated with erythropoietin.

BACKGROUND: Correction of anaemia as a result of renal failure improves cardiovascular function and also provides significant cognitive and emotional benefits. The most appropriate route for iron supplementation has not been determined for patients with chronic renal failure who are not yet on dialysis. METHODS: Forty-five anaemic patients with progressive renal insufficiency (PRI) were prospectively randomized to receive oral (ferrous sulphate 200 mg tds) or intravenous (300 mg iron sucrose monthly) iron treatment. Erythropoietin (rHuEpo) was simultaneously commenced and the dose adjusted according to a pre-established protocol. RESULTS: There were no significant differences in baseline patient characteristics between the two groups. The average follow-up was 5.2 months. Three patients suffered possible allergic reactions to iron sucrose. Haemoglobin response and changes in red cell hypochromasia were similar in the two groups, but serum ferritin was significantly higher in the intravenous group. The starting dose of rHuEpo could be temporarily discontinued in 43% of patients on oral iron and 33% of patients receiving iron sucrose (NS). rHuEpo was increased after 3 months in 9% of patients on oral iron and 19% of patients receiving iron sucrose (NS). Final doses of rHuEpo were 33.5 (0-66) and 41.6 (0-124) U/kg/week respectively in the oral and intravenous groups (NS). Although gastro-intestinal symptoms were more commonly reported in patients taking oral iron, these were mild according to scores on visual analogue scales. Dietary protein and energy intake were not significantly different in the two groups at 0, 3 and 6 months. CONCLUSIONS: In pre-dialysis patients, the efficacy of monthly 300 mg iron sucrose given intravenously is not superior with regard to haemoglobin response and rHuEpo dose as compared with a daily oral dose of 600 mg of ferrous sulphate or equivalent. Where intravenous iron is preferred, lower doses may help to reduce the incidence of allergic or "free iron" reactions, especially in patients with low body mass.