The effects of higher hemoglobin levels on mortality and hospitalization in hemodialysis patients

Background. The introduction of recombinant human erythropoietin for the treatment of anemia of chronic renal failure provided the opportunity to correct anemia in this patient population. The optimal target hemoglobin for patients with end-stage renal disease (ESRD) remains controversial. A large database of hemodialysis patients was analyzed to determine whether increasing hemoglobin level above the current Kidney Dialysis Outcomes Quality Initiative (K/DOQI) recommendations was associated with increased risk of mortality and hospitalization. Methods. A longitudinal study of hemodialysis patients in Fresenius Medical Care-North America facilities was performed. Selection was restricted to patients in the census for 6 consecutive months from July 1, 1998 through June 30, 2000. Patient mean hemoglobin and other covariates measured during the initial 6 months were related to survival, number of hospitalizations, and length of stay over the subsequent 6 months of follow-up. Results. Patients with hemoglobin <9 g/dL had an adjusted relative risk of death of 2.11 compared to those patients with 11 <= hemoglobin < 12 g/dL (P < 0.0001). The adjusted relative risk of death was 0.84 for 12 <= hemoglobin < 13 g/dL (P = 0.007). These data suggest there is no increased risk of mortality associated with hemoglobin above the current recommended values. Both number of hospitalizations and length of stay decreased as hemoglobin increased. Patients with hemoglobin greater than or equal to13 g/dL had an adjusted length of stay of 9.6 days compared to 10.9 days for those with 11 less than or equal to hemoglobin < 12 g/dL (P < 0.0001). Conclusion. These data indicate the relative risk of death and hospitalization are inversely associated with hemoglobin levels, with no apparent additional risk associated with hemoglobin levels > 12 g/dL.