title: Anemia in kidney transplants without erythropoietic agents: levels of erythropoietin and iron parameters.
abstract: OBJECTIVE
  To study the association between hemoglobin, endogenous erythropoietin (EPO) levels and ferric parameters in kidney recipients not treated with EPO-stimulating agents.
  
  
  METHODS
  Transverse study of 219 kidney transplant outpatients. The median time after transplantation was 54 months (P(25-75), 23-107). We assessed blood counts, ferric parameters, EPO levels, renal function (MDRD-4), and adjuvant treatment. We performed a linear regression analysis to predict hemoglobin.
  
  
  RESULTS
  Median EPO values were 14.05 mUI/mL (P(25-75) = 10.2-19.7). Applying the formulas described by Beguin, kidney transplant recipients showed a low observed/expected ratio of erythropoietin and of transferrin. Considering anemia to be an hemoglobin of < 12 g/dL in women and < 13 g/dL in men, 24.2% of subjects were anemic (n = 53), including 2.3% with hemoglobin < 11 g/dL. Anemic patients displayed worse renal function (49.2 ± 18.5 versus 55.46 ± 16.58 mL/min/1.73 m(2) in nonanemic; P = .021). There were no differences in C-reactive protein. The patients receiving a combination of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) showed the highest prevalence of anemia compared with other groups (42.9%, P = .027). EPO levels were significantly lower among patients treated with these drugs (P = .041), without differences in transferrin and ferritin. The percentage of anemic patients treated with mammalian target of rapamycin inhibitors (mTORi) was 31% versus 22.2% among those not receiving these immunosuppressants (P = .23). Although there were no differences in hemoglobin levels, patients treated with mTORi, showed higher EPO levels (P = .005) and lower mean corpuscular volume (P < .001). Regarding the etiology of chronic kidney disease, less frequently anemic patients were those with polycystic kidney disease (8.6% versus 26.7% in the rest, P = .021). The formula obtained by multiple linear regression to calculate hemoglobin was: hemoglobin = 11829-0909 log (EPG level) - 0455 (if female) + 0.010 0.013 transferrin + 0.013 creatinine clearance (r = .424, P < .001).
  
  
  CONCLUSIONS
  Treatment with ACEI and/or ARBs seemed to produce a defect in the synthesis of EPO, while those treated with mTORi, a hyporesponsive state.
authors.affiliation: Hospital Clinico San Carlos, Madrid, Spain. kiqueflorit@gmail.com
authors.forename: E A
authors.initials: EA
authors.lastname: Florit
authors.forename: F
authors.initials: F
authors.lastname: Hadad
authors.forename: B
authors.initials: B
authors.lastname: Rodriguez Cubillo
authors.forename: J C
authors.initials: JC
authors.lastname: De la Flor
authors.forename: F
authors.initials: F
authors.lastname: Valga
authors.forename: I
authors.initials: I
authors.lastname: Perez Flores
authors.forename: N
authors.initials: N
authors.lastname: Calvo Romero
authors.forename: R
authors.initials: R
authors.lastname: Valero San Cecilio
authors.forename: A
authors.initials: A
authors.lastname: Barrientos Guzman
authors.forename: A
authors.initials: A
authors.lastname: Sanchez Fructuoso
mesh_terms: D000328:Adult; D000368:Aged; D000740:Anemia / Q000097:blood* / Q000453:epidemiology*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000009:adverse effects; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D015994:Incidence; D007501:Iron / Q000097:blood*; D007668:Kidney / Q000503:physiopathology; D016030:Kidney Transplantation / Q000009:adverse effects*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D047428:Protein Kinase Inhibitors / Q000009:adverse effects; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D013997:Time Factors; D014168:Transferrin / Q000032:analysis
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D015415:Biomarkers; C554270:EPO protein, human; D006454:Hemoglobins; D007166:Immunosuppressive Agents; D047428:Protein Kinase Inhibitors; D014168:Transferrin; D004921:Erythropoietin; D005293:Ferritins; D007501:Iron; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases