FP447
A SYSTEMATIC REVIEW OF AVAILABLE REMOVAL TECHNIQUES OF PROTEIN BOUND TOXINS: A LIMITED PURSUIT

INTRODUCTION AND AIMS: Small water-soluble solutes, middle molecules and protein-bound sub-stances accumulate in the plasma of chronic kidney disease (CKD) patients. Although the efficacy of dialysis techniques for the removal of those uremic toxins has improved, the outcome of CKD patients still needs to be increased. Especially the removal of protein-bound substances might pro-tect patients from cardiovascular as well as other complications of uremia. However, the removal of protein-bound uremic toxins remains insufficient with currently available techniques. We therefore performed a systematic literature review to identify the most effective removal techniques for pro-tein-bound uremic toxins in chronic kidney disease patients.

METHODS: We performed a literature search in Pubmed and “World Of Science” to select studies comparing at least two different removal techniques for protein-bound substances in CKD patients published after the year 1980 and before December 31st, 2017.

RESULTS: 26 studies were identified investigating the four different types of removal techniques: hemodiafiltration (HDF), hemodialysis (HD), peritoneal dialysis (PD) or adsorption. Clearance rates (Cl), total solute removal (TSR) and reduction ratios (RR) were reported parameters to describe the efficacy of removal of protein-bound substances in these studies. The majority of the studies compared modulations of one technique and not different techniques against each other. Moreover, only a small number of studies reported similar quantifications for uremic toxins removal and only few studies assessed the removal of similar uremic toxins. Hence, study comparability was overall limited. A quality score was developed in the current analysis, giving ranking between the ranges of 1 to 5 to the following criteria; the number of patients involved in the study, the duration of the intervention, the number of protein-bound toxins analyzed and the study design. The overall average score was 3 of 5 points, with none of the studies scoring higher than 4 out of 5, demonstrating the limitation of the retrieved studies.

CONCLUSIONS: Although various techniques for the removal of protein-bound uremic solutes were investigated in the literature, none of the methods seems to be superior for the removal of protein-bound uremic toxins. Thus, the removal of protein-bound substances requires further improvement. The development of novel dialysis techniques and membranes might improve the efficacy of the removal of protein-bound substances and may therefore reduce the incidence and severity uremia-associated complications in the future. Based on the results of this study, a comparable guideline for any future research on CKD patients is essential and for this purpose e.g. the EUtox database (http://www.uremic-toxins.org/DataBase.html) might be a good starting point. Also maybe for future analysis representative uremic toxins could be used in any CKD study as a comparison key point.