title: The development of anemia is associated to poor prognosis in NKF/KDOQI stage 3 chronic kidney disease.
abstract: BACKGROUND
  Anemia is a common condition in CKD that has been identified as a cardiovascular (CV) risk factor in end-stage renal disease, constituting a predictor of low survival. The aim of this study was to define the onset of anemia of renal origin and its association with the evolution of kidney disease and clinical outcomes in stage 3 CKD (CKD-3).
  
  
  METHODS
  This epidemiological, prospective, multicenter, 3-year study included 439 CKD-3 patients. The origin of nephropathy and comorbidity (Charlson score: 3.2) were recorded. The clinical characteristics of patients that developed anemia according to EBPG guidelines were compared with those that did not, followed by multivariate logistic regression, Kaplan-Meier curves and ROC curves to investigate factors associated with the development of renal anemia.
  
  
  RESULTS
  During the 36-month follow-up period, 50% reached CKD-4 or 5, and approximately 35% were diagnosed with anemia (85% of renal origin). The probability of developing renal anemia was 0.12, 0.20 and 0.25 at 1, 2 and 3 years, respectively. Patients that developed anemia were mainly men (72% anemic vs. 69% non-anemic). The mean age was 68 vs. 65.5 years and baseline proteinuria was 0.94 vs. 0.62 g/24h (anemic vs. non anemic, respectively). Baseline MDRD values were 36 vs. 40 mL/min and albumin 4.1 vs. 4.3 g/dL; reduction in MDRD was greater in those that developed anemia (6.8 vs. 1.6 mL/min/1.73 m2/3 years). These patients progressed earlier to CKD-4 or 5 (18 vs. 28 months), with a higher proportion of hospitalizations (31 vs. 16%), major CV events (16 vs. 7%), and higher mortality (10 vs. 6.6%) than those without anemia. Multivariate logistic regression indicated a significant association between baseline hemoglobin (OR=0.35; 95% CI: 0.24-0.28), glomerular filtration rate (OR=0.96; 95% CI: 0.93-0.99), female (OR=0.19; 95% CI: 0.10-0.40) and the development of renal anemia.
  
  
  CONCLUSIONS
  Renal anemia is associated with a more rapid evolution to CKD-4, and a higher risk of CV events and hospitalization in non-dialysis-dependent CKD patients. This suggests that special attention should be paid to anemic CKD-3 patients.
authors.affiliation: Nephrology Department, Hospital Universitario Puerta de Hierro, Madrid, Spain. josem.portoles@salud.madrid.org
authors.forename: José
authors.initials: J
authors.lastname: Portolés
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Gorriz
authors.forename: Esther
authors.initials: E
authors.lastname: Rubio
authors.forename: Fernando
authors.initials: F
authors.lastname: de Alvaro
authors.forename: Florencio
authors.initials: F
authors.lastname: García
authors.forename: Vicente
authors.initials: V
authors.lastname: Alvarez-Chivas
authors.forename: Pedro
authors.initials: P
authors.lastname: Aranda
authors.forename: Alberto
authors.initials: A
authors.lastname: Martinez-Castelao
mesh_terms: D000328:Adult; D000368:Aged; D000740:Anemia / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011507:Proteinuria / Q000175:diagnosis / Q000453:epidemiology; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000453:epidemiology*; D012720:Severity of Illness Index; D055815:Young Adult