Efficacy of medium molecular weight toxin clearance in manual mixed online hemodiafiltration vs. pre- and post-dilution online hemodiafiltration and conventional hemodialysis: A crossover observational study

Abstract

The effectiveness of various hemodiafiltration (HDF) modes in removing different toxins is not fully understood. The present study aimed to compare the efficacy of manual mixed online HDF with pre-dilution online HDF, post-dilution online HDF, and conventional hemodialysis in clearing medium molecular weight toxins. Methods. This single-center, crossover observational study included 11 patients (7 males, 4 females) aged 48-85 years (mean age 65.2±11.7) with a dialysis vintage of 24-455 months (mean duration 126±123 months), including 10-29 months (mean duration 19.5±6.4) on HDF. The study focused on the removal of two medium molecular weight molecules: beta 2-microglobulin and the larger prolactin. The effectiveness of various dialysis modes was evaluated in single sessions for each patient, including pre-dilution online HDF (Group A), post-dilution online HDF (Group B), a mixed dilution model with post-dilution during the first half of the session and pre-dilution during the second half (Group C), and conventional hemodialysis (Group D). Results. A statistically significant difference in the reduction of serum beta 2-microglobulin levels was observed in Group B compared to Group A (70.6±3.1% vs. 64.4±2.7%, p<0.0001) and Group C (70.6±3.1% vs. 65.9±4.9%, p<0.001), with no significant difference between Groups A and C (p=NS). For serum prolactin levels, the greatest reduction was noted in Group B, with significant differences compared to Group A (52.5±8.9% vs. 36.2±9.5%, p<0.001) and Group C (52.5±8.9% vs. 46.9±5.2%, p=0.03). Additionally, Group C showed a significant difference compared to Group A (46.9±5.2% vs. 36.2±9.5%, p<0.005). Conclusions. Post-dilution HDF is the most effective mode for removing beta 2-microglobulin and prolactin. Mixed dilution HDF also shows significant efficacy, surpassing pre-dilution HDF in toxin clearance. These findings highlight the advantage of post-dilution techniques in managing medium molecular weight toxins. Further research is needed to explore these results in greater detail and to confirm their clinical implications.

Keywords

• hemodiafiltration, dilution techniques, beta 2-microglobulin, prolactin, clearance.