360 Short-term treatment with medium cut-off dialyzers increases muscle mass with preserved fat tissue in maintenance HD patients

Abstract Background and Aims Protein-energy wasting is a significant complication of maintenance hemodialysis (HD) patients characterized by reduced fat or muscle mass and strength. The combination of non-modifiable general and disease-related factors, such as uremic toxin accumulation and systemic inflammation, is responsible for this condition. Medium cut-off (MCO) membranes are designed to provide clearance of large-middle molecular weight uremic toxins and inflammatory cytokines without causing loss of albumin. This study aimed to investigate the short-term effect of MCO dialyzers on fat tissues and muscle mass. Method We conducted a prospective, single-center cross-over study on maintenance HD patients treated with regular low-flux (LF) dialyzers. Fat tissues were measured with a skinfold caliper and mid-upper arm circumference. Muscle thickness and strength parameters from six different muscle groups were evaluated with ultrasound. The baseline (control) parameters were measured under LF dialyzers, and the measurements were repeated two weeks after switching to MCO dialyzers for the patients ordered by their clinicians according to the clinical indications. Results The median age was 69.5 (50.3,78.8) years, and 60% of the patients were female. Two weeks after switching to MCO, the Kt/Vs, urea reduction ratios, mean serum albumin, dry weight, and body mass index scores were similar. Mean skinfold thickness and mid-upper arm circumference were 15 mm (11,17) and 28mm (27,30) under LF and 16mm (14,19) and 28mm (27,30) under MCO dialyzers (p=0.82 and p=0.27). Rectus abdominis and external oblique muscle groups remained similar. Internal and external oblique muscle thickness were significantly increased (p=0.002 and p=0.001). Mean rectus femoris and gastrocnemius medialis (GKM) thicknesses were 1.19cm (0.99,1.33) and 1.16cm (0.9,1.4) under LF and 1.31cm (1.20, 1.40) and 1.24cm (0.95,1.40) under MCO dialyzers (p=0.002 and p=0.02). Mean GKM fibrile length and pennation angles were 2.4cm (2.2,2.8) and 20o (18,23) under LF and 2.7cm (2.4, 2.9) and 22o (19,24) under MCO dialyzers (p=0.007 and p=0.001). Conclusion Our study showed that MCO dialyzers increase muscle mass with preserved fat tissues in HD patients, short-term follow-up. This favorable effect might be due to the clearance of uremic toxins, which cannot be removed with conventional methods. If long-term studies support our findings, MCO dialyzers would be a milestone for the treatment of sarcopenia i