ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005


The Latest on Twitter

Kidney Week

Abstract: PO1130

Online High-Volume Hemodiafiltration Reduces Pre-Dialysis Levels of Indoxyl Sulfate Compared with High-Flux Hemodialysis: Results from the HDFit Multicentric Randomized Controlled Trial

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • de Lima, Jordana Dinorá, Universidade Federal do Parana, Curitiba, PR, Brazil
  • Guedes, Murilo Henrique, Pontificia Universidade Catolica do Parana, Curitiba, PR, Brazil
  • Rodrigues, Silvia Daniele, Universidade Federal do Parana, Curitiba, PR, Brazil
  • Almeida, Ana clara Simões flórido, Pontificia Universidade Catolica do Parana, Curitiba, PR, Brazil
  • Barra, Ana Beatriz Lesqueves, Fresenius Medical Care, Rio de Janeiro, RJ, Brazil
  • Canziani, Maria Eugenia F., Universidade Federal de São Paulo, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Cuvello neto, Americo Lourenço, Hospital Alemão Oswaldo Cruz, São Paulo, SP, Brazil
  • Poli de Figueiredo, Carlos Eduardo, Pontificia Universidade Catolica do Rio Grande do Sul, Porto Alegre, RS, Brazil
  • Pecoits-Filho, Roberto, Pontificia Universidade Catolica do Parana, Curitiba, PR, Brazil
  • Nakao, Lia S., Universidade Federal do Parana, Curitiba, PR, Brazil

Although HDF improves the clearance and pre-dialysis concentration of middle size molecules, little is known about its effect on concentration of protein-bound uremic toxins (PBUT) particularly in comparison to HD. Here, we investigated whether HDF impacts pre-dialysis plasma levels of the PBUTs indoxyl sulfate (IxS), p-cresyl sulfate (pCS) and indole 3-acetic acid (IAA) compared to HD.


This is post-hoc analysis of the multicentric randomized controlled trial studying the impact of HDF versus hf-HD on measured physical activity (HDFit - NCT02787161), which included clinically stable HD patients with a vintage >3 to <24 months. Total plasma levels of IxS, pCS and IAA were determined by high performance liquid chromatography with fluorescence detection at baseline, 3 and 6 months. Mean difference in pre-dialysis PBUTs between HDF and hf-HD during the 6 months was estimated by linear mixed effect models.


One hundred ninety-three patients (mean age 53 years old, 70% males and 60% white) were analyzed. There were no differences between HD and HDF groups regarding clinical and biochemical characteristics at the baseline. In the HDF group, 99% of patients achieved a convective volume higher than 22 L. The mean differences (95% CI) in concentrations over time for PBUTs among HDF and HD groups are shown in the Figure.


In this post-hoc analysis of the HDFit trial, high-volume HDF consistently reduced pre-dialysis concentration of IxS compared to hf-HD. These results demonstrate the sustained effect of mixed-diffuse convective methods in the removal of PBUTs compared to predominantly diffuse techniques.

Figure - Mean differences between groups in the change from baseline along with 95% confidence intervals (CI). Results shown IxS favored by HDF compared to HD.