Normalizing hematocrit in dialysis patients improves brain function

Recombinant human erythropoietin (rHuEPO) treatment has been shown to impro ve brain and cognitive function in anemic dialysis patients. Significant de bate continues, however, regarding the appropriate target hematocrit (Hct) that will lead to the greatest benefits while considering possible side eff ects and costs of rHuEPO. Current practice results in an Hct averaging only 31% to 32% in dialysis patients, a level less than that achieved in the in itial clinical trials and well less than normal. This study was designed to evaluate dialysis patients at the current practice Hct levels versus norma l Hct levels (40% to 45%) to see if improvement in brain function resulted. Twenty patients with end-stage renal disease (ESRD) currently being treate d with rHuEPO (mean Hct, 31.6%) were administered additional rHuEPO to reac h normal Hct levels (mean, 42.8%). Electroencephalogram (EEG) frequency ana lysis showed a significant decrease in EEG slowing at greater Hct values, a nd the auditory oddball and Continuous Performance Task tasks yielded signi ficant electrode and time-by-electrode effects for P300 amplitude. Changes in P300 latency significantly correlated with increased Hct in the auditory oddball task. These findings suggest that further correction of anemia to normal Hct levels may result in continued improvement in neurocognitive fun ction by improving the ability to sustain attention in easier tasks and by enhancing the ability to recognize, discriminate, and hold stimuli in memor y for more difficult tasks. (C) 1999 by the National Kidney Foundation, Inc .