Single Session and Weekly Beta 2-Microglobulin Removal with Different Dialytic Procedures: Comparison between High-Flux Standard Bicarbonate Hemodialysis, Post-Dilution Hemodiafiltration, Short Frequent Hemodialysis with NxStage Technology and Automated Peritoneal Dialysis.

BACKGROUND: NxStage System One cycler (NSO) is a widespread system for home daily dialysis. Few data are available on the impact of this "low dialysate volumes system" on the removal rate of poorly diffusible, time-dependent solutes like ß2-microglobulin (ß2M). METHODS: Single-session and weekly balances of ß2M were performed and compared in 12 patients on daily NSO, 13 patients on standard high-flux bicarbonate dialysis (BHD), 5 patients on standard post-dilution on line hemodiafiltration (HDF), and 13 patients on automated peritoneal dialysis (APD). RESULTS: Intradialytic fall of plasma water ß2M levels (corrected for rebound) was 65.2 ± 2.6% in HDF, 49.8 ± 9.1% in BHD, and 32.3 ± 6.4% in NSO (p < 0.001 between all groups). Single treatment dialysate removal was much less in APD (19.4 ± 20.4 mg, p < 0.001) than in any extracorporeal technologies, and was less in NSO (126.2 ± 35.6 mg, p < 0.001) than in BHD (204.9 ± 53.4 mg) and HDF (181.9 ± 37.6 mg), with no differences between the latter 2; however weekly removal was higher in NSO (757.3 ± 213.7 mg, p < 0.04) than in BHD (614.8 ± 160.3 mg) and HDF (545.8 ± 112.8 mg). Extrapolated ß2M adsorption to the membrane was negligible in BHD, 14.7 ± 9.5% of total removal in HDF and 18.3 ± 18.5% in NSO. Integration of single session data into a weekly efficiency indicator (K × t) showed total volume of plasma cleared in NSO (33.4 ± 7.7 L/week) to be higher than in BHD (26.9 ± 7.2 L/week, p < 0.01) and not different than in HDF (36.2 ± 4.7 L/week); it was negligible (3.2 ± 1.0) in APD. CONCLUSIONS: Weekly ß2M removal efficiency proved equal and highest in HDF and NSO (at a 6/week prescription), slightly lesser in BHD and lowest in APD.