Anemia after kidney transplantation: Does its basis differ from anemia in chronic kidney disease?

BACKGROUND Although similar factors play a role in both PTA and anemia in patients with CKD, additional risk factors exist in the pathogenesis of PTA. The present study aimed at comparing anemia and inflammation-related parameters between RTx recipients and CKD patients and elucidating the risk factors of PTA. METHODS This single-centered, cross-sectional study consisted of 68 participants: 48 were in the RTx group and 20 were in the CKD group. The CKD patients were comparable to the RTx recipients in terms of age, gender, and eGFR. Serum levels of EPO, hepcidin, and IL-6 were measured by enzyme-linked immunosorbent assays. The ratio of EPO/Hb was calculated to estimate endogenous EPO resistance. RESULTS The prevalence of anemia was 46% in the RTx group and 30% in the CKD group (P = .23). RTx recipients had significantly lower Hb (P = .04), higher EPO (P < .001), and ferritin levels (P = .001), and higher EPO/Hb ratios (P < .001); however, CKD patients showed a higher frequency of absolute iron deficiency (P = .008). Neither hepcidin nor IL-6 levels differed between the two groups. Hb level of RTx recipients was correlated with only eGFR (r = .437, P = .002) but not with any of the transplantation-related factors, while Fe level was the only parameter to be correlated with Hb level of CKD patients (r = .622, P = .01). CONCLUSION In the present study comparing GFR-matched RTx and CKD patients, lower GFR level appears to be the factor most strongly associated with anemia, and endogenous EPO resistance is among the contributing factors to PTA.