Low-Volume Home Haemodialysis and In-Centre Haemodialysis: Comparison of Dialysis Adequacy in Obese Individuals

Abstract

Background Although frequent low-flow, low-volume haemodialysis using the NxStage System One is now well-established as an option for home therapy of end-stage chronic kidney disease, its ability to deliver adequate dialysis in people with high BMI remains questionable. This doubt may lead to obese individuals being denied the potential benefits of this modality. To establish if this doubt is justified, we compared dialysis adequacy in two groups of obese individuals; one receiving standard thrice-weekly in-centre haemodialysis and the other receiving frequent haemodialysis at home using the NxStage System One. Methods This is a retrospective observational cohort study of 105 adult dialysis patients with obesity (BMI ≥ 30 kg/m2). All had been on dialysis for at least six months. Fifty-five patients receiving in-centre haemodialysis were compared with 50 patients receiving home haemodialysis using NxStage System One. Dialysis adequacy (standard Kt/V calculated by the Daugirdas equation) was compared between the two groups. The clinical characteristics, laboratory test results, and treatment regimens of each group were also compared. Results The in-centre haemodialysis group was older (63.6 ± 12.8 years vs. 58.5 ± 10.9 years, p=0.033) and had a higher Charlson comorbidity score (5.9 ± 2.1 vs. 4.5 ± 2.5, p=0.003). Standard Kt/V was significantly higher in the home haemodialysis group (2.4 ± 0.5) than in the in-centre haemodialysis group (2.2 ± 0.2) (p = 0.006). The mean serum inorganic phosphate was significantly lower in the home haemodialysis group than in the in-centre haemodialysis group (1.6 ± 0.4 mmol/l vs. 1.8 ± 0.5 mmol/l, p = 0.010). There were no statistically significant differences in the usage of antihypertensives, phosphate binders, or erythropoiesis-stimulating agents between the two groups. Conclusions In this study, dialysis adequacy (expressed as standard Kt/V) was superior to that of standard thrice-weekly in-center haemodialysis delivered by frequent low-volume home haemodialysis using the NxStage System One. Hesitancy about recommending frequent low-volume home haemodialysis to obese individuals is therefore unjustified.

Keywords: comorbid obesity; haemodialysis (hd); home haemodialysis (hhd); in-centre haemodialysis; nxstage system one.

Figure 1. NxStage System One components and concept

Figure 1A: NxStage System One components. (A) System One: the main unit that contains fluid pumps and system controls with an integrated, easy-to-use interface. (B) Cartridge: a single-use, gamma-sterilized component that usually houses an integrated dialyzer. (C) PureFlow SL: the dialysate preparation system that purifies tap water and then combines it with concentrate to create dialysate. Figure 1B: NxStage System One concept. (A) The dialysate solution (prepared using the PureFlow SL or in premixed bags) passes across the dialyzer (green arrow path). (B) the patient’s blood passes across the dialyzer in a counter-current direction (red arrow path). (C) Used dialysate, waste, and excess fluids removed from the blood are routed through a waste line into a sink, toilet, or drain (yellow arrow path). (D) The filtered blood returns to the patient’s circulation (blue arrow path).

Figure 2. The means of standard Kt/V and serum inorganic phosphate by haemodialysis (HD) modality

Figure 3. The percentage of phosphate binder and erythropoiesis-stimulating agent (ESA) usage by the haemodialysis (HD) modality