Comparative Efficacy of Reused Medium Cut-Off Dialyzers on Uremic Toxin and Cytokine Clearance: A Randomized Controlled Trial

Introduction: Expanded hemodialysis using medium cut-off (MCO) dialyzers effectively removes middle-molecule uremic toxins, comparable to hemodiafiltration, but their single-use designation increases the dialysis costs. This study evaluated the efficacy and safety of reusing two MCO dialyzers available in Thailand. Methods: In this randomized controlled trial, hemodialysis patients were assigned to receive treatment with either Theranova® 500 or Elisio® 21HX dialyzers. Each dialyzer was reprocessed using peracetic acid and reused for up to 15 sessions. Dialyzer performance was assessed by the reduction ratios (RRs) of solutes, including β2-microglobulin (β2-MG), kappa and lambda free light chains (κ-FLC, λ-FLC), and interleukin-6 (IL-6), at baseline and the 2nd, 5th, 10th, and 15th sessions. Results: Forty-eight patients were enrolled (mean age 63.6 ± 13.7 years; 62.5% male) and randomized into 2 groups with comparable baseline characteristics. RRs for β2-MG, κ-FLC, and λ-FLC were similar between the groups and declined modestly over time after dialyzer reused (β2-MG: 78.2% to 72.5% vs. 77.2% to 74.5%, κ-FLC: 64.6% to 51.3% vs. 58.9% to 49.5%, and λ-FLC: 51.2% to 46.4% vs. 49.4% to 39.2% in the Theranova® 500 and Elisio® 21HX groups, respectively). Theranova® 500 demonstrated significantly higher IL-6 clearance in the 2nd (29.9% vs. 16.0%; p = 0.018) and 5th (23.8% vs. 7.7%, p = 0.031) sessions. It also showed a non-significant trend toward lower dialyzer survival (HR 3.98; p = 0.085) and higher, though clinically acceptable, albumin loss (mean difference 0.56 g/session; p < 0.001), which decreased with reuse. Conclusions: Both MCO dialyzers demonstrated comparable overall performance during reuse. Theranova® 500 provided better IL-6 clearance with manageable albumin loss. Implementation of high-quality dialyzer reuse protocols may optimize clinical efficacy and patient outcomes while balancing cost, accessibility, and environmental considerations.