A pilot, randomized, double-blind, cross-over study of high cut-off versus high-flux dialysis membranes.

Background: High cut-off (HCO) membranes may increase beta(2)-microglobulin (beta2M) removal compared to standard high-flux membranes.

Methods: Eight stable haemodialysis patients were enrolled in a prospective, randomized, double-blind, cross-over study and treated with HCO and high-flux membranes for 2 weeks each, between a 1-week washout period. Primary end point was serum beta2M removal. Secondary end points included serum albumin concentrations, albumin and small solute clearances.

Results: HCO membranes achieved significantly lower median post-dialysis beta2M concentration (10.8 vs. 14.2 mg/l; p = 0.003) and greater beta2M reduction ratio (62.3 vs. 51.0%; p < 0.002). Serum albumin decreased with HCO membranes (from 36 to 29.5 g/l; p = 0.018) but increased to 33.5 g/l after the washout period. Albumin clearance was significantly greater with HCO membranes (2.2 vs. 0.06 ml/min; p = 0.004). Urea reduction ratio was significantly lower with HCO membranes (64.8 vs. 71.5%; p < 0.001).

Conclusions: beta2M removal was superior with HCO membranes. Reduction in serum albumin and lower small solute clearance require further investigations.