Efficacy of polymethylmethacrylate membrane hemodiafilter Filtryzer® PMF™-21A in improving pruritus in hemodialysis patients: a prospective interventional study

Background Hemodialysis-associated pruritus (HAP) occurs in 60-80% of hemodialysis patients. This significant complication not only decreases quality of life through sleep disturbance and depression, but also leads to poor survival outcomes. The polymethylmethacrylate (PMMA) membrane was the first synthetic polymer membrane for the hollow-fiber artificial kidney created in 1977. PMMA membrane dialyzers have been reported to be effective for improving various complaints, including pruritus, and nutritional status. In Japan, a PMMA membrane hemodiafilter Filtryzer[R] PMF[TM]-A (PMF-A) was launched in November 2021 and subsequently became available for online hemodiafiltration (OHDF). This study aimed to determine whether PMF-A effectively improves pruritus in hemodialysis patients. Methods Participants were 20 patients (median age 74.5 years) on predilution OHDF (pre-OHDF) or postdilution OHDF (post-OHDF) using an Asymmetric Triacetate Membrane[R] hemodiafilter (FIX-210E eco or FIX-210S eco), who were experiencing pruritus of "very mild" or higher severity based on the Shiratori severity score either during the daytime or nighttime. After switching to post-OHDF with PMF-21A (substitution flow rate: 10 L/session), the substitution flow rate was gradually increased according to results of pruritus evaluation every 2 weeks over 3 months. The primary endpoint was the severity of pruritus evaluated using visual analogue scale (VAS) and the Shiratori severity score. Secondary endpoints included white blood cell count (WBC), hemoglobin level (Hb), platelet count (Plt), serum albumin level (Alb), high-sensitivity C-reactive protein (hsCRP), IL-6, dry weight (DW), and solute removal performance. Results The median VAS score was significantly decreased 2 weeks after switching compared with baseline (44 mm) and remained significantly decreased at Week 12 (22 mm; p < 0.01). From baseline to Week 12, 16 patients (80%) showed improvement in VAS score. The percentage of patients with mild to moderate daytime pruritus according to the Shiratori severity score decreased significantly from 80.0% to 45.0% (p < 0.05), whereas no significant change was observed for nighttime pruritus (p = 0.267). Pre-dialysis serum [beta].sub.2-MG levels were significantly higher at Week 12 compared with baseline. No significant changes were observed in WBC, Hb, Plt, serum Alb, hsCRP, IL-6, or DW. Conclusions OHDF with PMF-21A may be more effective in improving HAP. Keywords: Hemodialysis-associ