In line with this thinking, two RCTs comparing HDF to standard hemodialysis with either low- or high-flux membranes were performed. However, treatment assignment did not alter the primary outcome of all-cause mortality in neither of them. Interestingly, post‐hoc analyses from both trials unequivocally showed reduced mortality in the patient group achieving the highest convection volumes. Whether these data result from so‐called dose-targeting bias (the healthiest patients reaching the highest volumes) cannot be formally excluded, but it is noteworthy that these results remained after correction for known determinants of mortality. Moreover, careful examination of patients' baseline characteristics of the CONTRAST HDF cohort did not reveal a healthier profile among the high convection volume group.