A secondary analysis of the CHOIR trial shows that comorbid conditions differentially affect outcomes during anemia treatment

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.