Comparative efficacy between hemodialysis using super high-flux dialyzer with hemoperfusion and high-volume postdilution online hemodiafiltration in removing protein bound and middle molecule uremic toxins: A cross-over randomized controlled trial

The Revival of Sorbents in Chronic Dialysis Treatment

Interest in the use of sorbents in chronic dialysis treatment has undergone a revival in the last decades, for which two major factors are responsible. The first is the potential of sorbents as adjunct therapy for the removal of substances that are difficult to remove by conventional dialysis therapies. The second is their use in regeneration of dialysate, which is of pivotal importance in the design of portable or even wearable treatments, next to the potential for reducing water use during conventional dialysis treatment. Sorbent-enhanced dialysis with synthetic polymers was associated with a reduction in inflammatory parameters as compared to hemodialysis and even associated with improved survival in smaller studies, although this needs to be confirmed in large randomized trials. Incorporation of sorbents within a dialysis membrane (mixed matrix membrane) appears a promising way forward to reduce the complexity and costs of a dual therapy but needs to be tested in vivo. For regeneration of dialysate, at present, a combination of urease, zirconium-based sorbents, and activated charcoal is used. Next to sodium release by the sorbent in exchange for ammonium and the CO2 release by the hydrolysis of urea has been a bottleneck in the design of wearable devices, although short-term trials have been performed. Still, for widespread and flexible application of sorbent-assisted portable or wearable devices, a direct urea sorbent would be a major asset. In the near future, it will likely become apparent whether sorbent-assisted dialysis techniques are feasible for routine implementation in clinical practice.

Middle-size molecule clearance as measured by β2-microglobulin in high-flux versus low-flux dialysis and hemodiafiltration: A prospective randomized controlled trial

BACKGROUND

Whereas most studies to date have mainly concentrated on the comparison between high-flux hemodialysis (HFHD) and hemodiafiltration (HDF), or HFHD and low-flux hemodialysis (LFHD) in relation to the clearance of β2-microglobulin (β2M) in HD patients, there have been few related to combined HFHD and HDF therapy. To compare the clearance of middle-sized molecules as measured by β2M in HFHD versus LFHD and HDF.

METHODS

A prospective, single-center, open-label, observer-blinded, randomized controlled trial was conducted at the West China Hospital of Sichuan University in China. Patients received either HFHD or LFHD and HDF 3 times a week with follow-ups at one and 3 months. The primary endpoint was the clearance of β2M at 3 months. The secondary endpoints included hemodialysis-related adverse events, changes in anemia, states of nutrition, and inflammatory indices.

RESULTS

After 3 months of treatment, the HFHD+HDF group achieved a higher satisfaction level than the LFHD+HDF group, with decreased serum β2M concentrations (34.493 ± 7.257 vs. 43.593 ± 9.036 mg/L, p < 0.001) and elevated red blood cell counts (3.959 ± 0.742 vs. 3.602 ± 0.578 × 10¹² /L, p = 0.015). Compared with baseline, both kinds of treatment led to increases in serum urea (t = -3.623, p = 0.001 vs. t = -4.240, p < 0.001), cholesterol (t = -2.511, p = 0.016 vs. t = -4.472, p < 0.001), and magnesium (t = -2.648, p = 0.011 vs. t = -3.561, p = 0.001). An elevated level of serum albumin (t = -2.683, p = 0.010) was observed only in the HFHD+HDF group.

CONCLUSIONS

Combined therapy with HFHD and HDF has a beneficial effect on improving β2M clearance, red blood cell management, and nutrition status in HD patients.