Optimal convection volume for improving patient outcomes in an international incident dialysis cohort treated with online hemodiafiltration

Kidney Int. 2015 Nov;88(5):1108-16. doi: 10.1038/ki.2015.139. Epub 2015 May 6.


Online hemodiafiltration (OL-HDF), the most efficient renal replacement therapy, enables enhanced removal of small and large uremic toxins by combining diffusive and convective solute transport. Randomized controlled trials on prevalent chronic kidney disease (CKD) patients showed improved patient survival with high-volume OL-HDF, underlining the effect of convection volume (CV). This retrospective international study was conducted in a large cohort of incident CKD patients to determine the CV threshold and range associated with survival advantage. Data were extracted from a cohort of adult CKD patients treated by post-dilution OL-HDF over a 101-month period. In total, 2293 patients with a minimum of 2 years of follow-up were analyzed using advanced statistical tools, including cubic spline analyses for determination of the CV range over which a survival increase was observed. The relative survival rate of OL-HDF patients, adjusted for age, gender, comorbidities, vascular access, albumin, C-reactive protein, and dialysis dose, was found to increase at about 55 l/week of CV and to stay increased up to about 75 l/week. Similar analysis of pre-dialysis β2-microglobin (marker of middle-molecule uremic toxins) concentrations found a nearly linear decrease in marker concentration as CV increased from 40 to 75 l/week. Analysis of log C-reactive protein levels showed a decrease over the same CV range. Thus, a convection dose target based on convection volume should be considered and needs to be confirmed by prospective trials as a new determinant of dialysis adequacy.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • C-Reactive Protein / metabolism
  • Dialysis Solutions / administration & dosage*
  • Female
  • Follow-Up Studies
  • Hemodiafiltration / methods*
  • Humans
  • Kidney Failure, Chronic / blood
  • Kidney Failure, Chronic / mortality
  • Kidney Failure, Chronic / therapy*
  • Male
  • Middle Aged
  • Retrospective Studies
  • Survival Rate
  • Treatment Outcome
  • beta 2-Microglobulin / blood


  • Dialysis Solutions
  • beta 2-Microglobulin
  • C-Reactive Protein