Comparison of Volume Status in Asymptomatic Haemodialysis and Peritoneal Dialysis Outpatients

Abstract

Background: The majority of haemodialysis (HD) patients gain weight between dialysis sessions and thereby become volume overloaded, whereas peritoneal dialysis (PD) is a more continuous technique. Cardiovascular mortality and hypertension is increased with both treatment modalities. We therefore wished to compare volume status in PD and HD to determine whether PD patients are chronically volume overloaded, as a risk factor for cardiovascular mortality. Study Design, Setting and Participants:We retrospectively audited 72 healthy HD patients and 115 healthy PD patients attending a university hospital dialysis centre for routine outpatient treatment, who had multi-frequency bioimpedance measurements of extracellular water to total body water (ECW/TBW). Results: The groups were well matched for age, sex, weight and ethnicity, PD patients had greater urine output [1,075 (485–1,613) vs. 42.5 (0–1,020) ml/day, p < 0.001], but there was no difference in antihypertensive prescription (63.5 vs. 76.4%), mean arterial blood pressure (post-dialysis 101.6 ± 1.5 mm Hg vs. pre-dialysis 102 ± 2.4 mm Hg), although post-dialysis arterial blood pressure was lower than in PD patients (96.4 ± 3.1 mm Hg, p < 0.05). The ratio of ECW/TBW fell after HD (pre-dialysis 0.394 ± 0.001 vs. post-dialysis 0.389 ± 0.004, p < 0.001) and was similar in the PD group to the group before HD (0.393 ± 0.001), and greater than that in the group after HD (p < 0.001). ECW/TBW was greater than the normal reference range in 30% PD patients, 28% patients before HD and 20% patients after HD. Conclusions: Overhydration is common in healthy stable PD outpatients, and ECW volumes in PD patients are not dissimilar to those of pre-dialysis HD patients. The role of chronic volume overload as a risk factor for cardiovascular disease needs further investigation.

Impact of Diabetes on Extracellular Volume Status in Patients Initiating Peritoneal Dialysis

“…Previous reports have shown that while haemodialysis patients have a change in hydration status with dialysis sessions, PD patients generally experience volume expansion with an increased ECW/TBW ratio [10]. However, this ECW expansion does not necessarily reflect increased plasma volume, as ECW excess does not increase peritoneal ultrafiltration [7] or preserve residual renal function [11].…”

An Incident Cohort Study Comparing Survival on Home Hemodialysis and Peritoneal Dialysis (Australia and New Zealand Dialysis and Transplantation Registry)

“…Although none of these studies used PD as a comparison group, it is plausible that some of the known benefits of HHD over facility HD also apply when comparing HHD with PD. Indeed, although PD allows constant ultrafiltration, total fluid removal can sometimes be limited and possibly, lead to hypervolemia and hypertension (44)(45)(46)(47). Comparison of clearance quality between PD and HD is limited, although it seems reasonable to postulate that patients treated with long or long/frequent HHD receive a higher dialysis dose than most patients on PD.…”

The Effects of Racial Differences on Body Composition and Total Body Water Measured by Multifrequency Bioelectrical Impedance Analysis Influence Delivered Kt/V Dialysis Dosing

“…Multifrequency bioelectrical impedance analysis (MF-BIA) measurements were made after dialysis (InBody 720 Body Composition Analysis, Biospace, Seoul, South Korea) [18], using tetrapolar 8-point tactile electrodes [19]. Patients with cardiac pacemakers, implantable defibrillators, amputees and those unable to stand on the bio-impedance device were excluded.…”