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BACKGROUND AND AIMS HFR-Supra (haemodiafiltration with the regeneration of the ultrafiltrate) is a highly biocompatible dialysis technique characterized by an adsorptive resin cartridge with high protein-bound toxin adsorption capacity without removal of albumin, mimicking both glomerular and tubular functions. However, the low-flux dialyzer contained in the second diffusive stage of the HFR Supra system may hamper the removal of large uraemic toxins. This study assessed the large uraemic toxin removal ability of a new HFR system (HFR-H) which combines adsorption such as in HFR-Supra, with a high-efficiency high-flux haemodialysis membrane. METHOD In an open, randomized, cross-over, single-center, controlled study, 16 adult chronic haemodialysis patients were treated by haemodiafiltration with the regeneration of the ultrafiltrate with the HFR-Supra or the HFR-H system. All other dialysis parameters were kept constant in both study arms. All the treatments were delivered with Flexya dialysis monitor (Medtronic) in the middle-week session, lasting 4-h. The reduction rate (RR) of urea, creatinine, phosphate, β2-microglobulin, kappa (κFLC) and lambda (λFLC) free light chains and albumin, was intra-individually compared for the two dialysis types with linear mixed models. RESULTS The RRs for β2-microglobulin, κFLC and λFLC were significantly higher with the HFR-H system than those obtained with HFR-Supra (Figure). There were no significant differences in the RR for urea, creatinine, phosphate, interleukin-6 and albumin. CONCLUSION This study demonstrates that treating patients with an HFR-H instead of an HFR-Supra system significantly increases the elimination of middle and large molecules.

BACKGROUND AND AIMS Chronic kidney disease-associated pruritus (CKD-aP) is a very common symptom in dialysis patients and can significantly limit their quality of life and survival. While the prevalence of CKD-aP in peritoneal dialysis (PD) and in-center hemodialysis (HD) patients has been studied, little data are known for home HD (HHD) patients. The objective of this study was to analyse the prevalence of pruritus in HHD patients, and the factors associated with its presentation, as compared to PD and in-center HD patients. METHOD Cross-sectional, single-center study that included all patients on chronic dialysis treated at our center in November 2021. The patients were divided into three groups according to the dialysis modality (HHD, PD and in-center HD). All the patients answered a validated questionnaire on CKD-aP that evaluated the presence of itching, its intensity, frequency and location; the moment of appearance; the effect on quality of life, emotional state, cognitive function, sexual activity and quality of sleep. Likewise, it was assessed whether they had previously been diagnosed and treated for CKD-aP. The visual analogue scale (VAS) was used to define the intensity of itching as absent (VAS = 0), mild (VAS = 1–2), moderate (VAS = 3–6) or severe (VAS = 7–10). Clinical and analytical variables were compared between the groups, and the factors associated with the presence of pruritus were analysed using binary logistic regression. RESULTS Nighty-nine patients (41% women) were included, with a mean age of 64 ± 15 years and a median stay on dialysis of 57 (IQR: 17–159) months. The proportion of patients on HHD, PD and in-center HD was 20%, 41% and 39%, respectively. A total of 36% of the patients had some degree of pruritus, being mild, moderate, and severe in 8%, 13%, and 13% of the patients, respectively. The prevalence of pruritus and its intensity was similar in all the dialysis modalities (Figure 1). In the logistic regression analysis, the dialysis modality was not associated with presence of CKD-aP. CONCLUSION In our experience, the prevalence and intensity of pruritus was similar in HHD, PD and in-center HD patients. These data suggest that the type of dialysis techniques does not influence CKD-aP prevalence.

BACKGROUND AND AIMS Portable haemodialysis (HD) systems with a low dialysate flow rate in a short frequent schedule have become an attractive option for patients on home HD (HHD). Although these systems have been demonstrated to be effective for removing low weight molecular uraemic toxins, there are few data on their removal ability of higher molecular weight toxins. This study assessed the uraemic toxin removal ability of the portable Physidia S3 Monitor in a short, frequent, 5 days/week, low-dialysate flux HHD versus 3 days/week, in centre online haemodiafiltration (OL-HDF). METHOD In an open, randomized, cross-over, single-centre, controlled, prospective study, 40 adult chronic HD patients were treated by a 2.5-h low flux dialysate HD session or a 4-h post-dilution OL-HDF. All other dialysis parameters including dialyzer (polysulfone high-flux dialyzer NS 1.8, Toray®) were kept constant in both the study arms. The weekly reduction rate (RR) and the weekly eliminated mass into dialysate (EM) of urea, creatinine, phosphate, β2-microglobulin, kappa (κFLC) and lambda (λFLC) free light chains and albumin, were intra-individually compared for the two dialysis types with linear mixed models. RESULTS There were no significant differences in the RR for urea, phosphate, κFLC and albumin, whereas the weekly RRs for creatinine and β2-microglobulin were significantly higher with the Physidia S3 system than those obtained with OL-HDF (Table). Only the λFLC RR was significantly higher with OL-HDF. Similar results were observed when weekly EMs were compared (data not shown). CONCLUSION This study demonstrates that treating patients with low flow dialysate HHD in a short frequent schedule with Physidia S3 system, instead of 3 days/week, in-centre OL-HDF, significantly increases the weekly elimination of β2-microglobulin, enabling an adequate clearance of small and large uraemic toxins.

BACKGROUND AND AIMS The success of peritoneal dialysis (PD) depends on the integrity of the peritoneal membrane. The most common peritoneal functional alteration is an impaired ultrafiltration caused by fast peritoneal solute transfer rate. This situation can be present at start of PD and compromise the durability of the membrane through the stay on PD. If the patient leaves PD for another reason, as in the case of a kidney transplant, it affects the probability of a membrane dysfunction appearance. It is known as a competitive event. The aim of this study was to determine whether baseline peritoneal transport status was a risk factor of mortality and technique failure in a cohort of Spanish PD patients using a statistical competing risk model. METHOD The multicenter retrospective cohort study included adult patients of the Levante Registry PD Work Group in Spain who started PD between February 1993 and June 2020. All patients needed to have a peritoneal equilibration test (PET) performed within the first 6 months after PD start. Patients were followed until technique failure, transplantation, renal function recovery, death, or until September 2020. Peritoneal transport status was considered both as a continuous (D/PCr4h) and as a categorical variable, according to the four groupings of D/PCr values defined by Twardoski. We analysed the effect of peritoneal transport over mortality, peritonitis and technique failure by a competing risk model. Kidney transplantation and renal function recovery were considered competing events. RESULTS A total of 4848 patients were enrolled. Baseline PET measurements were available in 2.307 (47.6%). The median follow-up time was 22.2 months (IQR 11.5–40.5). The main characteristics according to the peritoneal transport status are summarized in Table 1. When peritoneal membrane transport was analysed as a continuous variable, D/PCr was an independent risk factor of technique failure. The hazard ratio subdistribution for technique failure was 1.08 [(1.01; 1.16), P-value = 0.018] for every 0.1 increase in D/P Cr ratio. This effect disappeared when the use of icodextrin was included in the model. Baseline peritoneal transport was not associated with a higher mortality or peritonitis risk. CONCLUSION Basal peritoneal transport rate is an independent risk factor for death-censored technique failure in the Levante DP incident population. The use of icodextrin in these patients seems to mitigate this negative effect and may improve the outcomes in PD in patients with initial fast transport. Conventional methods for survival analysis ignoring the competing events may be inappropriate this cohort of patients.