title: Reduction in beta2-microglobulin with super-flux versus high-flux dialysis membranes: results of a 6-week, randomized, double-blind, crossover trial.
abstract: BACKGROUND
  Uremic toxicity is a major concern in the dialysis population. There is keen interest in techniques that increase the removal of larger uremic molecules. We examined the short-term impact of a new, more porous, super-flux Helixone membrane (FX-E) versus the conventional high-flux Helixone membrane (FX-60) on beta(2)-microglobulin (beta2M) reduction and nutritional and inflammatory parameters.
  
  
  METHODS
  Randomized, double blind, crossover, pilot trial.
  
  
  METHODS
  A single freestanding dialysis center. 30 stable hemodialysis patients.
  
  
  METHODS
  Patients were treated with FX-60 and FX-E membranes for a treatment period of 6 weeks each, with a 2-week washout period in between.
  
  
  METHODS
  Primary outcome was change in beta2M concentrations from baseline to end of treatment. Serum samples were obtained predialysis and postdialysis at 0, 2, and 6 weeks, and dialysate albumin samples were collected continuously throughout dialysis sessions.
  
  
  RESULTS
  Mean postdialysis beta2M concentrations at the end of 6 weeks of treatment were 6.73 mg/L for FX-E versus 8.22 mg/L for FX-60, which was significantly lower overall by 0.69 mg/L (95% confidence interval [CI], -1.09 to -0.29; P = 0.001). beta2M reduction ratios were greater overall with FX-E by 4.83% (95% CI, 2.78 to 6.89; P < 0.001), with mean values of 57% for FX-60 versus 66% for FX-E at the end of treatment. Median dialysate albumin loss with FX-E was 1.23 g (range, 0.22 to 4.83 g) compared with 0.17 g (range, 0.0017 to 2.69 g) with FX-60, which was greater by 1.52 g (95% CI, 1.11 to 1.93; P < 0.001). Serum albumin concentrations were slightly lower with FX-E by 0.1 g/dL (0.55 g/L; 95% CI, -1.04 to -0.07; P = 0.03), but prealbumin concentrations were not significantly different at 8.53 mg/L (95% CI, -23.76 to 6.71; P = 0.3). There were no differences in inflammatory cytokine concentrations or small-solute removal.
  
  
  CONCLUSIONS
  Short-term pilot study.
  
  
  CONCLUSIONS
  In this stable dialysis population, removal of beta2M was more efficient with the Helixone super-flux FX-E membrane, with only a small decrease in albumin concentrations despite increased albumin loss. Large trials with longer treatment periods are required to evaluate the impact of the FX-E membrane on clinical outcomes.
authors.affiliation: Department of Nephrology, Monash Medical Centre, Clayton, Victoria, Australia. rebecca.pellicano@med.monash.edu.au
authors.forename: Rebecca
authors.initials: R
authors.lastname: Pellicano
authors.forename: Kevan R
authors.initials: KR
authors.lastname: Polkinghorne
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kerr
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001806:Blood Urea Nitrogen; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D017583:Hemodiafiltration / Q000295:instrumentation / Q000379:methods; D006436:Hemodialysis Units, Hospital; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000628:therapy*; D007677:Kidney Function Tests; D016014:Linear Models; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D010865:Pilot Projects; D012016:Reference Values; D006435:Renal Dialysis / Q000295:instrumentation* / Q000379:methods; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D001613:beta 2-Microglobulin / Q000378:metabolism*
chemical_list: D008567:Membranes, Artificial; D001613:beta 2-Microglobulin