Expanded Hemodialysis Versus Online Hemodiafiltration

Conventional hemodialysis (HD) is essential for the treatment of end-stage renal disease (ESRD) patients, by reducing serum concentration of uremic toxins and correcting fluid overload. Nevertheless, HD removes almost exclusively low-range uremic toxins. Therefore, medium-range molecules, such as beta-2-microglobulin might accumulate in tissues, leading to many clinical complications, such as neuropathies, tendinopathies, anemia, bone mineral disease and reduced growth in children. Convective methods might reduce incidence of these complications, by removing molecules of medium-range molecular weight. Online hemodiafiltration (olHDF) is the most extensively used method in this regard. Nevertheless, there are some barriers to the wider introduction of this method in clinical practice, since specific machines are needed for this procedure, the costs with dialysis lines are higher and water consumption increases. More recently, the development of new membranes for hemodialysis allowed removal of medium- and high-range uremic toxins, with albumin retention. Thus, they allow removal of a broad range of uremic toxins, without changing dialysis machine or increasing water consumption. Such therapy is known as expanded hemodialysis (HDx). The aim of this present study is to compare the extraction of middle-size molecules, the hemodynamic behavior, fluid and nutritional status of patients submitted to olHDF or HDx, in a crossover study.