In standard low flux hemodialysis (HD), toxins composed of large molecules are not cleared from the blood as effectively as toxins composed of small molecules. Hemodiafiltration (HDF) uses a greater volume of fluid to clear more molecules of larger size compared to both low flux and high flux HD. Although there is a widespread notion that HDF provides better patient survival than HD, results of previous studies have been mixed.
To help determine whether HDF does in fact lead to better outcomes, researchers examined data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) for 8,567 patients collected between 2009 and 2015. The sample included patients from seven European countries, with approximately 20 facilities from each country. Of the eligible patients, 2,012 (23 percent) were on HDF.
After multiple analyses to account for confounding variables, investigators found no evidence that HDF provides better patient survival than HD.
Lead author Dr. Francesco Locatelli added, “While from the theoretical point of view HDF is the most efficient dialysis technique, at present the evidence to support its use is weak even at high convective volumes.”
Compared to previous studies, including a prior analysis of DOPPS data, the current study has a much larger sample size, a larger proportion of patients using HDF, and more recent data. Because of these differences, results of this analysis may provide a more accurate representation of “real-world” settings than results of previous studies.
Further trials specifically designed to test the effect of different volumes of fluid are needed to adequately inform clinical practices.