Objective: To examine the effect of protein intake on the erythropoietic response of very low birth weight infants to treatment with recombinant human erythropoietin (rHuEPO).
Study design: Twenty very low birth weight infants were enrolled in the study and 19 completed the 6 weeks of study. Weekly absolute reticulocyte counts, protein intakes, and growth, as well as selected markers of protein metabolism--prealbumin, albumin, and transferrin--were analyzed. Iron stores were estimated for each infant to exclude iron deficiency as a cause of anemia. The relationship between protein intake and absolute reticulocyte count was evaluated with a linear breakpoint analysis to account for any plateau in the relationship at higher protein intakes.
Results: Adequate iron stores were present in all infants, and transferrin concentrations correlated with measured total iron-binding capacity (r = 0.95, p = 0.0001). In the rHuEPO-treated infants, absolute reticulocyte count was significantly associated with protein intake up to 3.1 gm/kg per day and extending to 3.5 gm/kg per day (p = 0.041 to 0.032); beyond this point there was no longer any effect. Moreover, in comparison with the infants who received placebo, the rHuEPO-treated infants had a better daily percent weight gain for a protein intake up to 3.5 gm/kg per day (p = 0.016).
Conclusions: In VLBW infants treated with rHuEPO, higher protein intake up to 3.1 to 3.5 gm/kg per day improved the erythropoietic response, and protein utilization for growth was improved. During treatment with rHuEPO, infants who receive adequate protein to achieve satisfactory growth also receive sufficient protein for erythropoiesis.