Factors affecting erythropoietin production and correction of anemia in kidney transplant recipients

Anemia does not correct in many kidney transplant recipients, probably due to iron deficiency or inadequate erythropoietin (Epo) production. We evaluated effects of iron (Fe) availability on correction of anemia in renal transplant recipients and sought to characterize patterns of early Epo production by transplanted kidneys as related to peritransplant factors. In a prospective randomized trial, 51 consecutive renal transplant patients were followed for 6 months. Epo was measured on days 0, 3, 14, 48 and 168 posttransplantation. Fe status was monitored on days 14, 48 and 168. Pts were randomized at day 14 based on Fe status. Iron-deficient (FeD) patients (n = 24) were randomized to receive daily Fe supplementation (FeDs, n = 12) or no supplementation (FeDns, n = 12). Those with normal Fe status (FeN, n = 27) were followed as controls. No differences were found between groups at day 0 for Hct, Cr, Epo, age, dialysis history, or type of donor. Day 3 Creatinine and Hct were similar among groups, while Epo was significantly higher in FeD groups vs FeN (p < 0.004), and continued higher at 6 months. Though each pt improved Hct, most FeDns and FeN were anemic and Fe deficient at 6 months while all FeDs patients had corrected their anemia (p ≤ 0.009) and Fe status. Four FeDs patients developed polycythemia. Epo production correlated inversely to cold ischemia time in cadaver renal allografts (p < 0.008). Donor age was significantly lower in the FeDs group than other groups (p ≤ 0.009) and was negatively correlated to Epo production in the 51 patients at day 3 (p ≤ 0.08). Fe deficiency worsens or develops during the first 6 months following transplantation in the majority of patients and Fe supplementation accelerates the correction of anemia following renal transplantation. Younger donors and less cold ischemia time potentiate the production of Epo by transplanted kidneys and, ultimately, the correction of anemia.