1. ¹Renal Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
2. ²Duke Clinical Research Institute, Durham, North Carolina, USA
3. ³Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina, USA
4. ⁴Cardiology Division, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
5. ⁵Department of Medicine, University College Galway, Galway, Ireland
6. ⁶The Duke Translational Research Institute, Durham, North Carolina, USA
7. ⁷Renal Division, Department of Medicine, University of Texas Southwestern, Dallas, Texas, USA
8. ⁸The Renal Division, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA

Correspondence: Lynda A. Szczech, Division of Nephrology, Department of Medicine, Duke University Medical Center, DUMC Box 3646, Durham, North Carolina 27710, USA. E-mail: szcze001@mc.duke.edu

Received 19 June 2009; Revised 11 September 2009; Accepted 15 September 2009; Published online 4 November 2009.

Abstract

The CHOIR trial in anemic patients with chronic kidney disease compared epoetin-alfa treatment with low (11.3 g/l) and high (13.5 g/l) hemoglobin targets on the composite end point of death, hospitalization for heart failure, stroke, and myocardial infarction. However, other anemia management trials in patients with chronic kidney disease found there was increased risk when hemoglobin is targeted above 13 g/dl. In this secondary analysis of the CHOIR trial, we compared outcomes among the subgroups of patients with diabetes and heart failure to describe the comparative relationship of treatment to these two different hemoglobin goals. By Cox regression analysis, there was no increased risk associated with the higher hemoglobin target among patients with heart failure. In patients without heart failure, however, the hazard ratio (1.86) associated with the higher target was significant. Comparing survival curves in an unadjusted model, patients with diabetes did not have a greater hazard associated with the higher target. Subjects without diabetes had a significantly greater hazard in the high as compared to the low target, but the interaction between diabetes and the target was not significant. We suggest that the increased risks associated with higher hemoglobin targets are not clinically apparent among subgroups with greater mortality risk. These differential outcomes underscore the need for dedicated trials in these subpopulations.