Anemia in chronic renal disease: evaluation of inflammatory activity on erythropoiesis and iron metabolism in patients not submitted to dialysis treatment.

BACKGROUND

Inflammatory activity is one of the factors involved in the physiopathology of anemia in patients with chronic kidney disease (CKD). The majority of studies on anemia, inflammation, and disturbances of iron metabolism have focused on patients in end-stage renal failure and dialysis therapy. However, anemia and inflammation are present in patients in previous stages of renal failure. The objective of this study was to evaluate the possible influence of inflammatory activity on erythropoiesis and iron metabolism in CKD patients without dialytic treatment.

METHODS

114 CKD adult patients were studied. Patients with anemia (n = 72) were compared with those without anemia (n = 46). Anemic patients were classified as renal anemia (n = 46) or iron deficiency anemia (n = 26). In addition the total group was analyzed according to the degree of renal dysfunction. Iron status, erythropoiesis activity (soluble transferrin receptor and erythropoietin determinations), and inflammatory activity (C-reactive protein, interleukin-6, interleukin-lp, and neopterin determinations) were measured using commercial kits. Reticulocyte hemoglobin content (Ret-Y) was also determined.

RESULTS

Interleukin-6, interleukin-li, and neopterin concentrations were higher in the anemic group when compared with those without anemia and controls. There was no difference in C-reactive protein values between CKD with and without anemia, although both of them had showed elevated levels when compared with controls. Ret-Y values were lower in iron deficiency anemia when compared with renal anemia and controls. An inverse correlation between interleukin-6 and hemoglobin (r = -0.4287, p= 0.0002) was observed only in the renal anemia group. It was observed that anemia has a tendency to worsen as renal function deteriorates. Reticulocyte count was lower and neopterin concentrations were higher in more advanced renal failure stages.

CONCLUSIONS

Inflammatory factors contribute to anemia in renal patients in all stages of renal failure. High levels of neopterin in CKD patients suggest that neopterin contributes to impaired erythropoietin production and anemia in CKD patients.