Hemoglobin predicts long-term survival in dialysis patients: a 15-year single-center longitudinal study and a correlation trend between prealbumin and hemoglobin

BACKGROUND: Dialysis patients have much higher mortality rates than the general population. Anemia is a common complication of uremia and a major contributor to morbidity and mortality in dialysis patients. The benefits of anemia correction using recombinant human erythropoietin (rHuEPO) are well established. Optimum hemoglobin level for dialysis patients remain controversial. We have investigated the association of enrollment hemoglobin with long-term survival in hemodialysis (HD) and peritoneal dialysis (PD) patients. METHODS: We enrolled 529 HD and 326 PD patients from 1987 and followed them to April 2003. Demographics, enrollment, and clinical and laboratory data were recorded. The Kaplan-Meier method was used to compute observed survival, and the multivariate Cox regression analysis was used to identify the independent predictors of mortality risk. RESULTS: Mean ages of HD and PD patients were 60 +/- 16 (SD) and 54 +/- 16 (SD) years, respectively. Forty-seven percent of HD patients and 41% of PD patients were diabetic. Mean enrollment hemoglobin levels of HD and PD patients were 9.44 +/- 1.9 and 9.61 +/- 1.77 g/dL respectively. Cumulative 15 year observed survivals of HD (P = 0.05) and PD (P = 0.032) patients with hemoglobin levels greater or equal to 12 g/dL were higher than those with hemoglobin levels less than 12 g/dL. Hemoglobin <12 g/dL was a better predictor of mortality in nondiabetics than diabetics, particularly in HD patients. Both in HD and PD diabetic patients, hemoglobin was not a significant predictor of mortality. By Cox regression analysis, after adjusting for age, race, gender, and months on dialysis at enrollment, the relative risk of mortality of patients with hemoglobin <12 g/dL was 2.13-fold (P = 0.008) higher for HD and 1.85-fold (P = 0.06) higher for PD compared to those with hemoglobin >/=12 g/dL (P = 0.035). A logistic regression analysis revealed a strong inverse relationship between the hemoglobin level and the odds risk of death in HD (OR = 0.83, P = 0.008) and in PD (OR = 0.85, P = 0.02) patients. CONCLUSION: Enrollment hemoglobin is a predictor of long-term survival in HD and PD patients. Patients with hemoglobin levels that are higher than current treatment recommendations (>12 g/dL) may benefit from long-term survival. Survival of dialysis patients may be improved by better management of malnutrition and anemia.