Factors Predicting Erythropoietin Responsiveness among Maintenance Hemodialysis Patients: Prospective Longitudinal Study

Aim: To characterize the longitudinal hemoglobin (Hgb) variability in response to erythropoietin (Epo) and to identify the influence of clinical factors on Hgb level and Epo responsiveness in a sample of hemodialysis (HD) patients using longitudinal statistical techniques.

Study Design: Prospective longitudinal study.

Place and Duration of Study: The study was conducted at the dialysis units in the Nephrology Hospital of the Armed Forces Medical Center at Cairo, Egypt, during one year duration.

Patients and Methods: The study was conducted on patients on maintenance HD who were subjected to an erythropoiesis stimulating agents (ESA) treatment. The time course of Hgb response to Epo therapy was analyzed in relationship to patients’ demographics, clinical and laboratory factors using individual growth curve modeling.

Results: Hgb levels of 89 studied patients regressed to a mean of 10.77 g/dl. The average slope of Hgb explained 12.6% of the variance in Hgb whereas an additional 8.66% was explained with the interaction of Epo dose with time. An Hgb change of -.116g/dl (P =.003) and -.124 (P =.000) was associated with non Epo use and non iron administration, respectively. Epo use was associated with a rate of Hgb change of .011g/dl per month per 10,000 IU (P =.042). An average Hgb change of .394(P =.040), .007(P =.000) and .601(P =.007) g/dl was associated with each unit increase in albumin, cholesterol and alkaline phosphates (ALP) concentrations respectively, while the rate of Hgb change was increased by .025(P=.046), .001(P=.005), .062(P=.024) and .024(P=.007) g/dl per month for each unit per month increase in albumin, cholesterol, ALP and calcium concentrations, respectively. Baseline Hgb was .128 higher (P =.000) and .449 lower (P =.000) for each unit increase in phosphorus and iPTH levels, respectively. Hospitalization lowered both baseline Hgb level by1.304 g/dl (P =.000) and the rate of change of Hgb by 1.022 g/dl per month (P =.000).

Conclusion: Laboratory values routinely measured at monthly intervals in HD patients could provide clinicians with a tool guide to predict Hgb response to Epo therapy for better anemia management in such population.