Superior dialytic clearance of beta(2)-microglobulin and p-cresol by high-flux hemodialysis as compared to peritoneal dialysis

Kidney Int. 2006 Aug;70(4):794-9. doi: 10.1038/ Epub 2006 Jul 5.


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.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Blood Urea Nitrogen
  • Creatinine / blood
  • Cresols / blood
  • Cresols / urine*
  • Cross-Sectional Studies
  • Female
  • Humans
  • Kidney / metabolism
  • Kidney Diseases / blood
  • Kidney Diseases / therapy*
  • Kidney Diseases / urine*
  • Male
  • Middle Aged
  • Peritoneal Dialysis / methods*
  • Phosphates / blood
  • Renal Dialysis / methods*
  • beta 2-Microglobulin / blood
  • beta 2-Microglobulin / urine*


  • Cresols
  • Phosphates
  • beta 2-Microglobulin
  • 4-cresol
  • Creatinine