Efficacy of Expanded Hemodialysis and Comparison with Standard Hemodialysis and Online Hemodiafiltration

Patients on standard hemodialysis (HD) show insufficient clearance of medium-molecular-weight uremic toxins, resulting in long-term complications. In this study we investigated the effectiveness of expanded HD (xHD) in the clearance of medium-molecular-weight uremic substances. This prospective study included patients on standard thrice-weekly HD. Participants were treated with xHD for 4 weeks, and the clearance of urea and β2-microglobulin was measured at the beginning and at the end of the study and compared with standard HD (sHD). Moreover, we investigated the clearance of Su-PAR, MCP-1, and activin, comparing sHD, xHD, and online hemodiafiltration (HDF). xHD had the same efficiency in the removal of low-molecular-weight substances compared to sHD but led to a significant decrease in β2-microglobulin levels from the first application of the method (sHD: from 36.9 ± 10.6 to 39.7 ± 18.9 mg/dL, p = 0.595 vs. 1st xHD: from 40 (36.5, 41.8) to 11 (9.8, 13.2) mg/dL, p = 0.008 vs. after 4 weeks on xHD: from 31.5 (28.5, 34.5) to 8.7 (8.2, 9.0) mg/dL, p = 0.008). Moreover, pre-session β2-microglobulin levels significantly decreased after 4 weeks on xHD. Su-PAR, MCP-1, and activin during xHD were also significantly reduced. xHD leads to a significant and cumulative reduction in medium-molecular-weight uremic toxins compared to standard HD.