Hemoadsorption/hemodialysis: current evidence and outcome on uremic toxin removal and symptom improvement

Patients on maintenance hemodialysis (MHD) still have a high burden of symptoms, even with current dialysis techniques. One main reason is that many uremic toxins are not fully removed. This is especially true for protein-bound uremic toxins (PBUTs) and inflammatory factors, which are insufficient to clear with diffusion or convection modality alone. Hemoadsorption combined with hemodialysis (HAHD) allows for the removal of a wider range of toxins, including middle to large molecules and PBUTs that are hard to pass the dialysis membrane. Moreover, HAHD can match different toxin properties and thereby improve overall clearance. Current studies show that HAHD can specifically increase the removal of PBUTs and inflammatory mediators. It may also reduce microinflammation in MHD patients. Some clinical evidence supports that HAHD can improve common symptoms in MHD patients, such as chronic kidney disease-associated pruritus, sleep disorders, and restless legs syndrome. In summary, HAHD is a reasonable blood purification modality to add on standard dialysis therapy and shows potential clinical benefits. When assessing the efficacy of HAHD, attention should be paid not only to changes in clinical factors but also to subjective experiences of patients. More studies are needed to define which patients benefit most and to confirm its effects on important outcomes such as hospitalization and survival. There is also a need for more high-quality clinical evidence to support the practice of HAHD and to achieve consensus on treatment standards and protocols.