Uremic toxins removal and iron status: a medium-term comparison between 4 dialysis techniques (EMPIRE study).

BACKGROUND

Recent evidence documented that dialyzers and hemodialytic techniques yield different dialytic performances. The study aims to compare uremic toxins removal and iron status between on-line hemodiafiltration (OL-HDF), high-flux hemodialysis (HF-HD), expanded hemodialysis (HDx), and HFR Aequilibrium (HFR-Aeq).

METHODS

A single-center retrospective observational study enrolled 52 patients on chronic HD. Each study group (HFR-Aeq, HDx, HF-HD, and OL-HDF) included 13 patients. Naïve patients for each of the treatments were considered. Serum samples were collected at baseline and after 12-24-48 weeks from the enrollment. Intragroup comparison was performed using Friedman's test whereas longitudinal data were compared using linear mixed models (LMMs).

RESULTS

HDx showed a progressive improvement in the removal of urea (p = 0.043), λ -free light chains (p = 0.033), and transferrin saturation (p = 0.011) compared to other techniques. A nearly significant slope of β2 M was observed (p = 0.066). Also HFR-Aeq showed a near significant reduction in λ FLC values (p = 0.05) and a nearly significant increase in albumin levels (p = 0.07).

CONCLUSIONS

HFR-Aeq provides uremic toxins removal comparable to other traditional techniques (HF-HD, OL-HDF). HDx confirmed its superiority in the removal of uremic toxins as urea and λ FLC and surprisingly enhanced TSAT by a possible anti-inflammatory effect not ascertained in the present study. The utilization of non-optimal convective volumes likely vanishes the promising findings of OL-HDF.