Biochemical comparison of 8 h haemodialysis and 4 h haemodiafiltration, and two dialysis membranes, in a randomized cross‐over trial. Issue 5 (17th April 2019) - Choo, Shi Z
ABSTRACT: Aim: Extended‐hours haemodialysis has long been regarded as the optimal form of dialysis for solute clearance. With emerging benefits of haemodiafiltration, we wanted to compare these two head‐to‐head. Methods: In this randomized cross‐over trial, we recruited existing nocturnal haemodialysis patients, who had not been hospitalized in the prior 3 months. After a baseline 8 h haemodialysis session, subjects were randomized to either 2 weeks of 8 h haemodialysis or 4 h haemodiafiltration with cross‐over to the alternative treatment after a 2‐week washout period. Subjects were additionally randomized to the Fresenius FX80 or Nipro Elisio in a parallel design. Blood and dialysate samples were collected at baseline and at the end of both study periods. Results: Twelve patients completed the study. Mean (SD) age and body mass index were 55.1 ± 11.5 years and 36.4 ± 10.8, respectively. Urea and creatinine reduction ratios were higher with extended‐hours haemodialysis compared to haemodiafiltration (difference 14.0%, 95% CI = 10.6, 17.3; P < 0.001 and 9.1%, 95% CI = 11.0, 7.2; P < 0.001). Fibroblast growth factor 23 (FGF23) clearance was superior with haemodiafiltration (difference 20.1%, 95% CI = 8.7, 31.6; P = 0.001). No difference was seen in reduction ratios for phosphate, retinol binding protein, alpha‐1‐microglobulin, beta‐2‐microglobulin and fetuin with both modalities. Compared to Nipro Elisio, Fresenius FX80 dialyser achieved higher beta‐2‐microglobulin clearance (Period 1: difference 7.8%, 95% CI = 1.3, 14.4; P = 0.02, Period 2:7.5%, 95% CI = 1.0, 14.1; P = 0.02). Conclusions: Small solute clearance was superior with extended‐hours haemodialysis while haemodiafiltration enhanced FGF23 clearance. Beta‐2‐microglobulin clearance was improved with Fresenius FX80 dialyser, but this difference is unlikely to be clinically significant. Summary at a Glance: This small randomized cross‐over trial compared solute clearance between patients on 8 h extended haemodialysis and 4 h haemodiafiltration over a period of 2 weeks, and found that the former was associated with superior urea and creatinine clearance while the latter enhanced FGF23 clearance.