title: Erythropoietic response and outcomes in kidney disease and type 2 diabetes.
abstract: BACKGROUND
  Non–placebo-controlled trials of erythropoiesis-stimulating agents (ESAs) comparing lower and higher hemoglobin targets in patients with chronic kidney disease indicate that targeting of a lower hemoglobin range may avoid ESA-associated risks. However, target-based strategies are confounded by each patient's individual hematopoietic response.
  
  
  METHODS
  We assessed the relationship among the initial hemoglobin response to darbepoetin alfa after two weight-based doses, the hemoglobin level achieved after 4 weeks, the subsequent darbepoetin alfa dose, and outcomes in 1872 patients with chronic kidney disease and type 2 diabetes mellitus who were not receiving dialysis. We defined a poor initial response to darbepoetin alfa (which occurred in 471 patients) as the lowest quartile of percent change in hemoglobin level (<2%) after the first two standardized doses of the drug.
  
  
  RESULTS
  Patients who had a poor initial response to darbepoetin alfa had a lower average hemoglobin level at 12 weeks and during follow-up than did patients with a better hemoglobin response (a change in hemoglobin level ranging from 2 to 15% or more) (P<0.001 for both comparisons), despite receiving higher doses of darbepoetin alfa (median dose, 232 μg vs. 167 μg; P<0.001). Patients with a poor response, as compared with those with a better response, had higher rates of the composite cardiovascular end point (adjusted hazard ratio, 1.31; 95% confidence interval [CI], 1.09 to 1.59) or death (adjusted hazard ratio, 1.41; 95% CI, 1.12 to 1.78).
  
  
  CONCLUSIONS
  A poor initial hematopoietic response to darbepoetin alfa was associated with an increased subsequent risk of death or cardiovascular events as doses were escalated to meet target hemoglobin levels. Although the mechanism of this differential effect is not known, these findings raise concern about current target-based strategies for treating anemia in patients with chronic kidney disease. (Funded by Amgen; ClinicalTrials.gov number, NCT00093015.)
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02114, USA. ssolomon@rics.bwh.harvard.edu
authors.forename: Scott D
authors.initials: SD
authors.lastname: Solomon
authors.forename: Hajime
authors.initials: H
authors.lastname: Uno
authors.forename: Eldrin F
authors.initials: EF
authors.lastname: Lewis
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Eckardt
authors.forename: Julie
authors.initials: J
authors.lastname: Lin
authors.forename: Emmanuel A
authors.initials: EA
authors.lastname: Burdmann
authors.forename: Dick
authors.initials: D
authors.lastname: de Zeeuw
authors.forename: Peter
authors.initials: P
authors.lastname: Ivanovich
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Levey
authors.forename: Patrick
authors.initials: P
authors.lastname: Parfrey
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Remuzzi
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Singh
authors.forename: Robert
authors.initials: R
authors.lastname: Toto
authors.forename: Fannie
authors.initials: F
authors.lastname: Huang
authors.forename: Jerome
authors.initials: J
authors.lastname: Rossert
authors.forename: John J V
authors.initials: JJ
authors.lastname: McMurray
authors.forename: Marc A
authors.initials: MA
authors.lastname: Pfeffer
mesh_terms: D000368:Aged; D000740:Anemia / Q000188:drug therapy* / Q000209:etiology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control; D016009:Chi-Square Distribution; D000068256:Darbepoetin alfa; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000401:mortality; D004311:Double-Blind Method; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D006397:Hematinics / Q000627:therapeutic use*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007279:Injections, Subcutaneous; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012306:Risk; D020521:Stroke / Q000453:epidemiology
chemical_list: D006397:Hematinics; D006454:Hemoglobins; D004921:Erythropoietin; D000068256:Darbepoetin alfa