Expanded Hemodialysis Versus High-Volume Online Hemodiafiltration for Uremic Toxin Removal

People with advanced kidney disease need dialysis to remove waste products from the blood. Some of these waste products, called uremic toxins, are small, while others are medium-sized and more difficult to remove. Poor removal of these toxins may contribute to symptoms and long-term complications in patients on dialysis. Two dialysis techniques are commonly used to improve toxin removal beyond standard hemodialysis: expanded hemodialysis (HDx) using medium cut-off membranes, and high-volume online hemodiafiltration (HV-OL-HDF). Although both techniques are effective, the best way to prescribe expanded hemodialysis-particularly the ideal treatment time-has not been clearly defined. The purpose of this study is to compare how well different treatment times of expanded hemodialysis remove small and medium-sized uremic toxins, and to compare these results with high-volume online hemodiafiltration. Toxin removal will be evaluated using a combined measurement called the Global Removal Score, which summarizes the removal of several important waste substances. This is a single-center, randomized, open-label, crossover study. Adults receiving maintenance hemodialysis will receive three different expanded hemodialysis sessions with different treatment durations (180, 210, and 240 minutes), followed by one session of high-volume online hemodiafiltration. Blood samples will be taken before and after each dialysis session to measure toxin levels. The results of this study may help determine whether expanded hemodialysis with shorter or standard treatment times can achieve toxin removal similar to high-volume hemodiafiltration, which could support more personalized and practical dialysis prescriptions.