title: Phosphate equilibration rate and daily clearance in patients on CAPD, CCPD and APD.
abstract: BACKGROUND
  Criteria for how to assess removal rate of inorganic phosphorous (iP) in peritoneal dialysis (PD) and whether iP removal differs between different PD modalities are debated.
  
  
  METHODS
  In a cross-sectional study, 73 prevalent patients on continuous ambulatory PD (n = 16), continuous cyclic PD (n = 8) or automated PD (n = 49) with mean age 54 (range, 18-87) years, 46 males, underwent standard peritoneal equilibration test (PET) and 24-hour collection of dialysate with measurements of iP, urea and creatinine in all samples and bags. There were 11 slow, 53 average, and 9 fast transporters.
  
  
  RESULTS
  D/P ratios for iP and creatinine at 4 h of PET were strongly correlated (ρ = 0.86, p&lt;0.0001). Allocation of patients into slow, average and fast transporters according to D/P ratios for iP and creatinine was essentially similar. Whereas the weekly peritoneal clearance of iP (30.8 ± 16.6 L/wk) was lower than that of creatinine (38.4 ± 14.9 L/wk), clearances were strongly correlated (ρ = 0.89, p&lt;0.0001). The correlation between peritoneal weekly clearance of iP and urea KT/V was however weak (ρ = 0.56, p&lt;0.0001. CAPD patients had higher iP clearance than APD patients, 43.2 ± 14.9 versus 24.7 ± 13.4 L/wk (p&lt;0.05); however, serum iP concentrations did not differ.
  
  
  CONCLUSIONS
  Creatinine is a good surrogate marker for phosphate removal, both as assessed by PET and by 24 hours' clearance, in different PD modalities. Therefore, a separate PET scale for phosphate may not be needed. iP removal was greater with CAPD than APD but serum phosphate levels did not differ.
authors.affiliation:  Renal Unit, RTS Versalles, Cali - Colombia.
authors.forename: Rafael
authors.initials: R
authors.lastname: Gomez
authors.affiliation:  Institute of Biocybernetics and Biomedical Engineering, Warsaw - Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Waniewski
authors.affiliation:  Renal Unit, RTS Versalles, Cali - Colombia.
authors.forename: Adelaida
authors.initials: A
authors.lastname: Zapata
authors.affiliation:  Institute of Biocybernetics and Biomedical Engineering, Warsaw - Poland.
authors.forename: Mauro
authors.initials: M
authors.lastname: Pietribiasi
authors.affiliation:  Baxter Novum and Renal Medicine, Karolinska Institutet, Stockholm - Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Lindholm