Association between Erythropoietin Responsiveness and Body Composition in Dialysis Patients

Abstract

Background: In contrast to the general population, in maintenance hemodialysis (MHD) patients, small body size is correlated with reduced survival. The reasons for this association are unclear but may be related to a lower uremic toxin load relative to body weight and a higher distribution volume for uremic toxins in large patients. Since anemia is a salient feature in dialysis patients, this study aimed to explore the relationship between body composition and anemia control. Methods: Total adipose tissue (TAT), subcutaneous adipose tissue (SAT) and muscle mass (MM) were estimated by regression models in African-American MHD patients. Patients were grouped for further analysis by gender in tertiles of TAT, SAT, and MM. Analysis of covariance with age and serum albumin as covariates was employed to test for differences in hemoglobin (Hgb, g/dl), erythropoietin use (EPO, U/kg b.w./week), and EPO resistance index (ERI, U/kg b.w./week/Hgb). Results: 479 patients were studied (50.5% females). In both genders, EPO dose and ERI were lower the higher the tertile of TAT and SAT (all p < 0.02). In females, EPO and ERI were inversely related to tertiles of MM (p ≤ 0.001). No difference in Hgb concentration was observed. Conclusion: Anemia control is related to body composition in Black dialysis patients. EPO requirements and EPO resistance are reduced in patients with high TAT, SAT and MM (the latter in females only). A lower uremic load in large dialysis patients may contribute to these findings.