Background: The HEMO Study was a randomized clinical trial designed to determine whether increasing hemodialysis dose above current standards, or using high-flux membranes, would improve patient outcome. The primary results of the trial showed no statistically significant effects of either dialysis dose or membrane flux on the primary outcome of mortality.
Methods: This report examines the implications of secondary analyses involving subgroups and secondary outcome measures for the overall interpretation of the trial.
Results and conclusions: The secondary analyses of the HEMO Study do not alter the conclusions of the primary analysis: In the context of conventional three times per week hemodialysis, neither the high-flux nor high-dose interventions substantially improved patient outcome compared to low-flux and standard-dose levels. However, certain secondary results from the trial are consistent with the hypothesis of subtle effects that may be magnified by more intensive therapies that extend beyond the limits of conventional three times per week dialysis. This hypothesis will be addressed by a pair of new randomized trials sponsored by the National Institute of Digestive and Kidney Disease (NIDDK), which will compare six times per week daily and nocturnal therapies with conventional three times per week dialysis.