More effective clearance of variously sized uremic toxins and inflammatory cytokines occurs after online hemodiafiltration (Ol-HDF) than expanded hemodialysis (HDx), according to findings from a small trial.
Compared with conventional HD, expanded HD using a medium cut-off (MCO) membrane dialyzer with larger pore sizes improves the removal of medium- and large-middle molecule uremic toxins. What was unknown is how expanded HD compares with HDF.
In a trial, Eakalak Lukkanalikitkul, MD, of Khon Kaen University, in Thailand, and colleagues randomly assigned 40 patients requiring thrice-weekly maintenance hemodialysis to receive post-dilution Ol-HDF or HDx using the MCO dialyzers Theranova 500® or Elisio HX21®.
Compared with the HDx group, the Ol-HDF group, with a mean convection volume of 24.7 L, had significantly higher reduction ratios after the first session in beta-2 microglobulin (82.8% vs 74.6%), parathyroid hormone (80.4% vs 60.6%), homocysteine (58.0% vs 50.0%), kappa-free light chains (73.3% vs 64.6%), and lambda-free light chains (62.5% vs 52.0%), the investigators reported in Scientific Reports. There were no differences between modalities in phosphate and IL-6 clearance. Toxin levels before each dialysis session were similar between groups. Serum albumin loss after the sessions did not differ between groups. The Ol-HDF group had significantly higher equilibrated urea Kt/V values compared with the HDx group: 1.8 vs 1.5.
In the HDx arm, both MCO dialyzers showed similar effectiveness in removing uremic toxins.
Intradialytic hypotension occurred more frequently in the HDx than Ol-HDF group.
"These findings highlight that Ol-HDF demonstrated superior removal of uremic toxins, while HDx was comparable to Ol-HDF in maintaining pre-dialysis levels of middle molecules and inflammatory cytokines," the investigators concluded.
Future research should study a wider range of toxins, particularly those with higher molecular weights, including protein-bound uremic toxins, according to the investigators.
References:
Lukkanalikitkul E, Kidkaem H, Phonrat M, Prathompong P, Anutrakulchai S. A randomized trial comparing medium cut-off membrane dialyzers with online hemodiafiltration for uremic toxins clearance in hemodialysis patients. Sci Rep. 2025;15(1):5467. doi:10.1038/s41598-025-89197-5