Determination of Dialysis Dose: A Clinical Comparison of Methods

Background: Guidelines recommend regular measurements of the delivered hemodialysis dose Kt/V. Nowadays, automatic non-invasive online measurements are available as alternatives to the conventional method with blood sampling, laboratory analysis, and calculation. Methods:In a prospective clinical trial, three different methods determining dialysis dose were simultaneously applied: Kt/V Dau (conventional method with Daugirdas’ formula), Kt/V OCM [online clearance measurement (OCM) with urea distribution volume V based on anthropometric estimate], and Kt/V BCM [OCM measurement with V measured by bioimpedance analysis (Body Composition Monitor)]. Results:1,076 hemodialysis patients were analyzed. The dialysis dose was measured as Kt/V Dau = 1.74 ± 0.45, Kt/V OCM = 1.47 ± 0.34, and Kt/V BCM = 1.65 ± 0.42. The difference between Kt/V OCM and Kt/V BCM was due to the difference between anthropometric estimated V Watson and measured V BCM . Compared to Kt/V Dau , Kt/V OCM was 15% lower and Kt/V BCM 5% lower. Kt/V Dau was incidentally prone to falsely high values due to operative errors, whereas in these cases OCM-based measurements Kt/V OCM and Kt/V BCM delivered realistic values. Conclusions:The automated OCM Kt/V OCM with anthropometric estimation of urea distribution volume was the easiest method to use, but Kt/V BCM with measured urea distribution volume was closer to the conventional method.