Is online hemodiafiltration superior to hemodialysis in removal of indoxyl sulfate in chronic hemodialysis patients? A comparative study

Abstract

Background Indoxyl sulfate (IS) is a protein-bound small molecule that is poorly cleared by conventional hemodialysis and has potential toxicity. This study aimed to evaluate the superiority of online hemodiafiltration (HDF) over hemodialysis for the removal of IS in patients undergoing maintenance hemodialysis. Patients and Methods Sixty patients undergoing maintenance hemodialysis were enrolled in this prospective, randomized comparative study. Patients were randomly allocated to three groups: online post-dilution HDF, high-flux hemodialysis (HFHD), and low-flux hemodialysis (LFHD). Each group consisted of 20 patients. Serum total IS (tIS) levels were measured pre- and post-dialysis. The tIS removal rate was assessed by calculating the tIS reduction ratio (tISRR). Results Serum tIS levels decreased significantly after dialysis in all groups (all P < 0.001). The mean tISRR did not differ significantly between the HDF and HFHD (24.20 ± 10.73 vs. 19.70 ± 14.31%, P = 0.449) or between HFHD and LFHD (19.7 ± 14.3 vs. 13.5 ± 9.52%, P = 0.229). The ISRR for HDF was significantly higher than that for LFHD (24.2 ± 10.7 vs. 13.5 ± 9.52%, P = 0.015). Regression analysis did not show significant differences in ISRR between the HDF and HFHD groups, even after controlling for covariates (P = 0.160). Conclusion The study showed that online HDF had no additive effect on tIS removal compared to HFHD; however, it was superior to LFHD.