title: Superior dialytic clearance of beta(2)-microglobulin and p-cresol by high-flux hemodialysis as compared to peritoneal dialysis.
abstract: Both residual renal and dialytic clearance confer to the total solute clearance in dialysis patients. Dialytic clearances of the middle molecule beta-microglobulin (beta(2)M) and the protein-bound solute p-cresol (pcr) are generally believed to be higher with peritoneal dialysis (PD) as compared to hemodialysis (HD). Supportive data, however, are lacking. We performed a single-center cross-sectional observational study including 70 unselected patients treated with either high-flux HD (n=20) or PD (n=50). Mid-day serum levels (PD) and time-averaged concentrations (HD) of the water-soluble solutes urea nitrogen, creatinine and phosphate, the middle molecule beta(2)M, and the protein-bound solute pcr were determined. Dialytic solute clearances (l/week/1.73 m(2)) were calculated from total dialysate collection during the mid-week session in HD and 24 h dialysate collection in PD. Renal clearances were calculated for each of the respective solutes from a timed urine collection. Total clearances were obtained by summation. HD delivered significantly higher clearances of all retention solutes studied. This superiority was especially pronounced for pcr (30.9+/-62.7 vs 4.4+/-2.3, HD vs PD, P<0.0001) and beta(2)M (28.6+/-6.6 vs 5.8+/-3.1, HD vs PD, P<0.0001). Renal clearances, conversely, were significantly higher in patients on PD. Serum levels of all solutes but pcr were significantly lower in HD than in PD. Both a higher residual renal function and a lower generation rate contribute to the lower pcr levels in PD. In conclusion, superior dialytic clearance of both water-soluble solutes, beta(2)M, and pcr is achieved by high-flux HD as compared to PD.
authors.affiliation: Department of Medicine, Division of Nephrology, University Hospital Leuven, Leuven, Belgium. pieter.evenepoel@uz.kuleuven.ac.be
authors.forename: P
authors.initials: P
authors.lastname: Evenepoel
authors.forename: B
authors.initials: B
authors.lastname: Bammens
authors.forename: K
authors.initials: K
authors.lastname: Verbeke
authors.forename: Y
authors.initials: Y
authors.lastname: Vanrenterghem
mesh_terms: D000328:Adult; D000368:Aged; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D003408:Cresols / Q000097:blood / Q000652:urine*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism; D007674:Kidney Diseases / Q000097:blood / Q000628:therapy* / Q000652:urine*; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000379:methods*; D010710:Phosphates / Q000097:blood; D006435:Renal Dialysis / Q000379:methods*; D001613:beta 2-Microglobulin / Q000097:blood / Q000652:urine*
chemical_list: D003408:Cresols; D010710:Phosphates; D001613:beta 2-Microglobulin; C032538:4-cresol; D003404:Creatinine