Efficiency and Safety of Different Medium Cut-Off Membranes in Maintenance Hemodialysis Patients

Due to the accumulation of uremic toxins, hemodialysis patients exhibit a variety of symptoms and increased mortality. With their unique pore size and distribution, medium cut-off (MCO) membranes can provide clearance of middle-sized uremic toxins without causing albumin loss. Such a property may decrease overall mortality in hemodialysis patients. This study aims to analyze the effects of MCO membranes on the clearance of β₂-microglobulin, tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) to assess the safety of using these membranes and to compare two different MCO membranes.

This was a prospective observational study. Sixty hemodialysis patients who had been dialyzed thrice weekly via high flux dialyzers were switched to one of two MCO dialyzers (Elisio Hx or Theranova) for 1 month. The mean age was 58.7 ± 13.4 years, and the mean dialysis vintage was 65.8 ± 58.6 months. Serum levels of β₂-microglobulin, TNF-α, and IL-6 were compared by paired-samples t test between the end and the beginning of the study period. Dialysis adequacy, electrolytes, heparin doses, low-density lipoprotein (LDL), hemoglobin, and albumin levels were also compared. In addition, the performance of the two MCO dialyzers was compared using an independent-samples t test.

There was a significant decrease in β₂-microglobulin (p = 0.02), LDL (p < 0.01), and albumin levels (p < 0.001) at the end of the study. Dialysis adequacy, hemoglobin, phosphorus, C-reactive protein, IL-6, and TNF-α levels did not change significantly. Among patients receiving standard heparin for anticoagulation, heparin doses had to be increased during MCO membrane use. The performance of the two different dialyzers was not statistically different.

MCO membranes provide clearance of middle-sized uremic toxins. This effect is most prominent for β₂-microglobulin and does not differ between the two MCO dialyzers studied. MCO membranes may cause some albumin loss, and heparin requirements may increase during their use.