Beta-2 microglobulin removal with postdilution online hemodiafiltration - comparison of three different dialysis membranes

Introduction. Accumulation of middle molecular weight uremic toxins causes various complications in chronic hemodialysis (HD) patients. Postdilution online hemodiafiltration (OL-HDF) efficiently removes these molecules. This study aimed to assess the effectiveness of three different dialysis membranes in removing β2- microglobulin (β2m) within a single session of postdilution OL-HDF. Method. A prospective single-center study was carried out in 30 patients (23 males and seven females, average age 54.87 ± 11.66 years, time on dialysis 4.95 ± 5.4 years) on maintenance HD. Each patient was followed for three consecutive weeks on OL-HDF with three different dialyzers: DiacapPro 19H, FX CorDiax 800, and Elisio 21H, randomly switched weekly. The reduction ratios (RR) of β2m and albumin were compared individually. The results were analyzed with the Kolmogorov–Smirnov test, ANOVA, and the Kruskal–Wallis test. Results. The average convective volume for all patients was 21.38 ± 2.97 L/session. β2-m RR was 70.86 ± 6.87%, 74.69 ± 6.51%, and 70.04 ± 9.37% with Diacap Pro 19H, FX CorDiax 800 and Elisio 21H membrane, respectively (p = 0.054). Albumin RR was 6.20 ± 2.12% with Diacap Pro 19H membrane, 6.01 ± 2.97% with FX CorDiax 800 membrane, and 6.46 ± 2.91% with Elisio 21H membrane (p = 0.812). Albumin loss was < 4 g/dialysis treatment for all membranes. Conclusion. All investigated membranes effectively remove β2-m in postdilution OL-HDF with a tolerable albumin loss. The highest β2-m RR was determined for FX CorDiax 800 membrane, but with no statistically significant difference