Comparison of uremic toxin removal between expanded hemodialysis and high volume online hemodiafiltrations in different modes

Various high-efficiency hemodialysis techniques exist, including different online high- volume hemodiafiltration (HDF) modes and expanded hemodialysis (HDx) utilizing dialyzers with medium cut-off (MCO) membranes. This study aimed to evaluate the efficacy of uremic toxin removal among four modalities: (I) HDx, (II) pre-dilution HDF (PRE-HDF), (III) mixed-dilution HDF (MIX-HDF), and (IV) post-dilution HDF (POST-HDF), each applied for 1 week in a randomized order. This research was a single-center, prospective, open-label, exploratory crossover study. The reduction ratio (RR) for small molecular toxins (urea and phosphate), a middle molecular toxin (beta-2-microglobulin, β2M), a large-middle molecular toxin (Chitinase-3-like protein 1, YKL-40), and a protein- bound uremic toxin (indoxyl sulfate, IS) was evaluated during a single mid-week dialysis session. Twelve patients were included, with an average age of 52.5 ± 15.47 years and an average dialysis duration of 42.05 ± 31.04 months. The dialysis parameters, including; post-dialysis weight, session duration, dialysate composition, blood and dialysate flow; rates, dialysate temperature, and anticoagulation dosage, were maintained consistently across all modalities. No significant differences in RR for urea, phosphate, β2M, YKL-40, and IS were observed between the treatments. Although the highest IS clearance, though not statistically significant, was observed with POST-HDF and HDx, the differences were not substantial enough to favor any particular modality as the most effective.