Clinical advantages of a newly launched anti-thrombotic PMMA membrane for the nutritional status and dialysis-related symptoms in older chronic dialysis patients: a multicenter pilot study

Malnutrition that is associated with inflammation is a key factor of poor outcome in chronic hemodialysis patients, especially in older dialysis patients. Polymethyl methacrylate (PMMA) membrane has been reported to improve the inflammatory status by removing pro-inflammatory cytokines via adsorption. However, older dialysis patients occasionally have multiple uncomfortable dialysis-related symptoms, which decrease their quality of life and survival rate. We investigated whether a new PMMA membrane, Filtryzer NF, can improve malnutrition and dialysis-related symptoms in older hemodialysis patients. Patients over 70 years of age who were dialyzed using a polysulfone (PS) membrane were enrolled and randomly allocated into one of two groups: control or NF. In the NF group, the PS dialyzers were changed to NF, whereas in the control group, the PS membrane was continuously used. The primary outcome was the malnutrition–inflammation score (MIS). Secondary outcomes were C-reactive protein, normalized protein catabolism rate, percent of creatinine generation rate, arm circumference, and eight dialysis-related symptoms. The primary and secondary outcomes were measured every 3 months for 1 year. Fifty-four hemodialysis patients were randomly assigned to the NF group (n = 28) or the control group (n = 26). During the 12-month study period, 11 and 10 patients were withdrawn from the NF and control groups, respectively. There was no significant difference in the MIS between the groups during the study or between the beginning and the end of the study within each group. For the secondary outcomes, there was a significant reduction in the total score of dialysis-related symptoms in the NF group but not in the control group. During the study period, the total dialysis-related symptoms score in the NF group was significantly decreased from 6 (range, 1–16) to 3 (range, 0–11) (median [minimum–maximum], p < 0.05). Other secondary outcomes were not different between the groups or between the beginning and the end of the study. This study showed no advantage for the nutritional status in older hemodialysis patients using NF compared with PS. However, our results indicated that NF may improve several dialysis-related symptoms. To clarify this clinical finding, large-scale prospective randomized clinical trials are required. This study was registered with the Clinical Trials Registry of the University Hospital Medical Information Network (registration ID, UMIN000032990 ).