Primary results of the PREDICT (Darbepoetin Alfa in CKD Patients with Non-Diabetic Kidney Disease) trial did not show improvement with darbepoetin alfa in renal outcomes with a higher hemoglobin target (11-13 g/dL) with compared with a lower hemoglobin target (9-11 g/dL) in patients with advanced chronic kidney disease (CKD) without diabetes. To further study the effects of higher hemoglobin level targets on renal outcomes, researchers, led by Shoichi Maruyama, MD, performed prespecified secondary analyses.
In the PREDICT study, patients with estimated glomerular filtration rate (eGFR) 8 to 20 mL/min/1.73 m2 without diabetes were randomly assigned 1:1 to either the high hemoglobin group or the low hemoglobin group. A mixed-effects model in the full analysis set and in a per-protocol set that excluded patients with off-target hemoglobin levels were used to examine differences between the groups in slopes of eGFR and proteinuria. The groups were also compared for the primary end point of composite renal outcome in the per-protocol set using the Cox model.
In the full analysis set, (high hemoglobin, n=239; low hemoglobin, n=240), there were no statistically significant differences between the two groups in eGFR and proteinuria slopes. In the per-protocol set (high hemoglobin, n=136; low hemoglobin, n=171), there was an association between the high-hemoglobin target and reduced composite renal outcomes (adjusted hazard ratio, 0.64; 95% CI, 0.43-0.96) and an improved eGFR slope (coefficient: +1.00 mL/min/1.73 m2/year; 95% CI, 0.38-1.63). There was no difference between the two groups in the proteinuria slope.
In summary, the authors said, “In the per-protocol set, the high-hemoglobin group demonstrated better kidney outcomes than the low-hemoglobin group, suggesting a potential benefit of maintaining higher hemoglobin levels in patients with advanced CKD without diabetes.”