Association of Continuous-Equivalent Urea Clearances with Death Risk in Intermittent Hemodialysis

Background. Several reports describe favorable results fromfrequent hemodialysis, but due to the lack of unequivocal dose measures it is not clear whether the benefits are due to more efficient toxin removal or other factors. Methods. The associations with death risk of six continuous-equivalent urea clearance measures were compared in 57 conventional in-center hemodialysis treatment periods of 51 patients, together 114 patient years. The double pool dose measures were calculated with the Solute-Solver program and separately scaled to urea distribution volume or normalized with body surface area. Results. Mortality associated significantly with equivalent renal urea clearance (EKR) scaled to urea distribution volume () ( = 0.033) and with EKR normalized with body surface area (BSA) ( = 0.044) but not with -scaled ( = 0.059) nor BSA-normalized ( = 0.183) standard clearance (stdK). Women had significantly higher normalized protein catabolic rate (nPCR), EKR/, and stdK/ than men but slightly lower BSA-normalized dose measures and lower mortality. Protein catabolic rate and dialysis dose correlated positively with each other and with survival. Conclusions. The prognostically most valid continuous-equivalent clearance in the present material was EKR/, calculated from double pool urea generation rate, distribution volume, and time-averaged concentratio