title: Factors related to the absence of anemia in hemodialysis patients.
abstract: BACKGROUND
  A small number of hemodialysis (HD) patients have normal hemoglobin (Hb) levels without the need for erythropoiesis-stimulating agents (ESAs). The factors associated with this condition have been little studied. The objective of this prospective study was to determine these factors in a prevalent population of HD patients.
  
  
  METHODS
  All patients who had normal Hb levels and who had not received ESAs in the last 6 months (non-ESA group) were included. Epidemiological and laboratory data were collected and we performed an abdominal ultrasound to assess hepatic and renal cysts. This group was compared to a control group of 205 prevalent HD patients on ESA therapy (control group).
  
  
  RESULTS
  We included 45 patients (16% from the whole group) in the non-ESA group. In this group, there was a higher proportion of men (76.5 vs. 61%), patients were younger (61.1 ± 14.7 vs. 67.5 ± 15.2 years), had a longer duration of renal replacement therapy (RRT) (9.4 ± 8.3 vs. 5.3 ± 5.8 years) and had a higher prevalence of adult polycystic kidney disease (APKD) and hepatitis C virus (HCV) liver disease (42.2 vs. 10.2%), p < 0.01. In the non-ESA group, HCV+ patients had a lower prevalence of APKD (2.2 vs. 38.4%) and hepatic cysts (2.2 vs. 19.2%), but significantly higher endogenous erythropoietin levels (55.8 ± 37.1 vs. 30.9 ± 38.4 mU/ml). No significant differences in anemia, iron metabolism, insulin, IGF-1 and renin were found between non-ESA and control groups. Non-ESA patients had a significantly higher number of renal (90.6 vs. 36.5%) and hepatic cysts (12.5 vs. 3.4%), and these were also larger in size (3.3 ± 2.4 vs. 1.5 ± 0.8 cm). In the multivariate Cox analysis, independent predictor factors for absence of anemia in HD patients were number of renal cysts >10 cysts (95% CI 1.058-1.405; p = 0.00), HCV+ liver disease (95% CI 1.147-1.511; p = 0.05) and time on RRT (95% CI 1.002-1.121; p = 0.05).
  
  
  CONCLUSIONS
  The absence of anemia in HD patients is not infrequent. Its frequency is higher in men and younger patients with long-term RRT, in patients with HCV+ liver disease and in APKD. It is associated with increased endogenous erythropoietin production and the presence of renal and hepatic cysts.
authors.affiliation: Servicio de Nefrología, Hospital General Universitario Gregorio Marañon, Madrid, Spain. ursulaverdalles@yahoo.es
authors.forename: Ursula
authors.initials: U
authors.lastname: Verdalles
authors.forename: Soraya
authors.initials: S
authors.lastname: Abad
authors.forename: Almudena
authors.initials: A
authors.lastname: Vega
authors.forename: Caridad
authors.initials: C
authors.lastname: Ruiz Caro
authors.forename: Jara
authors.initials: J
authors.lastname: Ampuero
authors.forename: Rosa
authors.initials: R
authors.lastname: Jofre
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Lopez-Gomez
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000628:therapy / Q000821:virology; D003560:Cysts; D004921:Erythropoietin / Q000378:metabolism*; D005260:Female; D006397:Hematinics / Q000008:administration & dosage; D016174:Hepacivirus / Q000502:physiology; D006526:Hepatitis C / Q000097:blood* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000628:therapy / Q000821:virology; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology*; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000628:therapy / Q000821:virology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016891:Polycystic Kidney, Autosomal Dominant / Q000097:blood* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000628:therapy / Q000821:virology; D015995:Prevalence; D011446:Prospective Studies; D006435:Renal Dialysis; D013154:Spleen / Q000473:pathology; D014463:Ultrasonography
chemical_list: D006397:Hematinics; D004921:Erythropoietin