The impact of hemodiafiltration with endogenous reinfusion (HFR) on micronutrient status in patients undergoing maintenance hemodialysis: A randomized crossover trial.

Background: Micronutrient deficiencies are common in patients undergoing maintenance hemodialysis (MHD), potentially contributing to adverse clinical outcomes. Hemodiafiltration with endogenous reinfusion (HFR) integrates convection, diffusion, and adsorption, potentially preserving essential nutrients better than traditional online hemodiafiltration (HDF). This study aimed to compare the acute effects of HFR and HDF on serum micronutrient concentrations in MHD patients.

Methods: The research has been registered in chictr.org.cn (ChiCTR2500096698). In this randomized crossover trial, 30 adult MHD patients received one session each of HFR and HDF, separated by a 2-week washout period consisting of their standard maintenance hemodialysis. Blood samples were collected pre- and post-treatment for trace elements and vitamin concentrations. The primary outcome was post-treatment serum iodine concentration, chosen to assess the acute dialytic clearance efficiency of iodine. Secondary outcomes included changes in serum concentrations of other trace elements and water- and fat-soluble vitamins. Linear mixed models (LMM) were used for between-treatment comparisons, and paired tests for within-group changes.

Results: A total of 30 patients (mean age 55.7 ± 14.8 years; 63.3 % male) completed the study. No significant difference was observed in post-treatment serum iodine between HFR and HDF (adjusted mean difference: -0.019 μmol/L, p = 0.343). However, HFR was associated with significantly greater reductions in serum calcium, vitamin D3, and selenium, compared to HDF (p < 0.05 for all). In contrast, vitamin B3 concentrations were significantly higher after HFR (p = 0.047). No serious adverse events occurred, and both modalities were well-tolerated.

Conclusions: While HFR did not significantly differ from HDF in iodine clearance, it resulted in greater losses of calcium, vitamin D3, and selenium, but resulted in significantly higher post-treatment serum concentrations of vitamin B3. These findings suggest that until long-term studies demonstrate a clear net benefit, the routine clinical implementation of HFR outside of dedicated research contexts appears premature and requires significant caution.