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

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