Normalization of hematocrit with recombinant human erythropoietin in chronic hemodialysis patients does not fully improve their exercise tolerance abilities

In the recombinant human erythropoietin (rHuEPO) treatment of renal anemia, the target level has widely been accepted as approximately 30% of hematocrit (Hct) which means only partial improvement of the anemia. We tried to maintain 1 female and 9 male patients within a normal Hct and to estimate their exercise tolerance abilities. During the study, no serious complications were experienced. Their maximal oxygen uptake (VO2max), evaluated for 1-6 months after reaching the desired Hct of 35-40% with rHuEPO, was 30.7 +/- 2.4 ml of O2/kg/min. These results were significantly higher than those of the control groups whose Hct levels were maintained at around 30%. Although 1 female and 2 male patients were considered to be within the normal exercise tolerance abilities, the others showed lower values in comparison with the Japanese age- and sex-matched values. Thus, it is not always possible to regain full exercise tolerance abilities even after restoring a normal Hct. Unknown factors besides anemia impairing their exercise tolerance abilities might exist in chronic dialysis patients.