title: Impact of using two dialyzers in parallel on phosphate clearance in hemodialysis patients: a randomized trial.
abstract: BACKGROUND
  Dietary restriction and phosphate binders are the main interventions used to manage hyperphosphatemia in people on hemodialysis, but have limited efficacy. Modifying conventional dialysis regimens to enhance phosphate clearance as an alternative approach remains relatively unstudied.
  
  
  METHODS
  This was a 10-week, 2-arm, randomized crossover study. Participants were prevalent dialysis patients ( n = 32) with consecutive serum phosphate levels >1.6 mmol/L and on stable doses of a phosphate binder. Following a 2-week run-in period, participants were randomized to initiate dialysis using two high flux dialyzers in parallel (blood flow ≥350 mL/min, dialysate flow 800 mL/min) or standard dialysis using one high flux dialyzer (blood flow ≥350 mL/min, dialysate flow of 800 mL/min). Each regimen was 3 weeks in duration. After a 2-week washout period, participants received the alternate regimen. The primary outcome was the mean difference in phosphate clearance by dialyzer strategy. Secondary outcomes were phosphate removal and pre-dialysis serum phosphate.
  
  
  RESULTS
  Phosphate clearance for the double dialyzer strategy did not differ significantly from the single dialyzer strategy [mean difference 7.5 mL/min (95% confidence interval, 95% CI, -6.1, 21.0), P = 0.28]. There was no difference in total phosphate removal and pre-dialysis phosphate between the double and single dialyzer strategies [total phosphate removal mean difference -0.2 mmol (95% CI -4.1, 3.7), P = 0.93; pre-dialysis mean difference 0.01 mmol/L (95% CI -0.18, 0.21), P = 0.88]. There was no difference in the proportion of participants who experienced at least one episode of intradialytic hypotension (32 versus 47%, P = 0.13). A limitation of the study was frequent protocol deviations in the dialysis prescription.
  
  
  CONCLUSIONS
  In this study, the use of two dialyzers in parallel did not increase phosphate clearance, phosphate removal or pre-dialysis serum phosphorus when compared with a standard dialysis treatment strategy. Future studies should continue to evaluate novel methods of phosphate removal using conventional hemodialysis.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Thompson
authors.affiliation: Departments of Medicine and Community Health Sciences, University of Calgary, Calgary, Canada.
authors.forename: Braden
authors.initials: B
authors.lastname: Manns
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Anita
authors.initials: A
authors.lastname: Lloyd
authors.affiliation: Departments of Medicine and Community Health Sciences, University of Calgary, Calgary, Canada.
authors.forename: Brenda
authors.initials: B
authors.lastname: Hemmelgarn
authors.affiliation: Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: MacRae
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Klarenbach
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada.
authors.forename: Larry
authors.initials: L
authors.lastname: Unsworth
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Courtney
authors.affiliation: Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Marcello
authors.initials: M
authors.lastname: Tonelli
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada; D018592:Cross-Over Studies; D015314:Dialysis Solutions / Q000008:administration & dosage*; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D054559:Hyperphosphatemia / Q000097:blood / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000097:blood*; D006435:Renal Dialysis / Q000379:methods*
chemical_list: D015314:Dialysis Solutions; D010710:Phosphates
keywords: ESRD; clinical trial; dialysis; dialysis adequacy; phosphatemia