title: Factors Contributing to Erythropoietin Hyporesponsiveness in Patients on Long-Term Continuous Ambulatory Peritoneal Dialysis: A Cross-Sectional Study.
abstract: BACKGROUND
  Factors contributing to erythropoietin (EPO) hyporesponsiveness in patients on long-term continuous ambulatory peritoneal dialysis are not well understood. Therefore, we investigated the factors contributing to EPO hyporesponsiveness using the EPO resistance index (ERI).
  
  
  METHODS
  A total of 14 patients (7 males and 7 females, age 65.0 ± 11.9 years) were selected for this study. We defined ERI as the weekly dose of EPO per body weight divided by hemoglobin (U/kg/g/dl/week). Bioelectrical impedance analysis was used to assess the patients' body composition and fluid status. We examined associations between ERI and clinical parameters, such as physiological, chemical and nutrition status, by correlation and multiple linear regression analyses.
  
  
  RESULTS
  Peritoneal dialysis duration was 95 ± 23 months, and all patients underwent peritoneal dialysis for >5 years. Hemoglobin, blood pressure and ultrafiltration volume of peritoneal dialysis were 11.5 ± 1.2 g/dl, 123 ± 14/72 ± 8 mm Hg and 834 ± 317 ml/day, respectively. Renal Kt/V and peritoneal Kt/V, which are indices of dialysis adequacy, were 0.32 ± 0.31 and 1.70 ± 0.31, respectively. Age and extracellular water/total body water (ECW/TBW) ratio had significant positive correlations with ERI (both p < 0.05). Levels of C-reactive protein, serum albumin, parathyroid hormone and normalized protein catabolic rate were not significantly correlated with ERI. In a multiple regression analysis, ECW/TBW was independently associated with ERI (p < 0.05).
  
  
  CONCLUSIONS
  This study demonstrates that ECW/TBW was a factor contributing to ERI and that appropriate maintenance of body fluid volume could contribute to low EPO dosing.
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hara
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Mukai
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Nakashima
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Rikako
authors.initials: R
authors.lastname: Sagara
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Masahide
authors.initials: M
authors.lastname: Furusho
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Miura
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Toyonaga
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sugawara
authors.affiliation: Department of Nephrology and Kidney Center, Aso-Iizuka Hospital, Iizuka City, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Takeda
keywords: Erythropoietin hyporesponsiveness; Erythropoietin resistance index; Extracellular water/total body water; Long-term continuous ambulatory peritoneal dialysis