Effect of online hemodiafiltration on all-cause mortality and cardiovascular outcomes

Haemodiafiltration versus haemodialysis for kidney failure: an individual patient data meta-analysis of randomised controlled trials

BACKGROUND

High-dose haemodiafiltration has been shown, in a randomised clinical trial, to result in a 23% lower risk of mortality for patients with kidney failure when compared with conventional high-flux haemodialysis. Nevertheless, whether treatment effects differ across subgroups, whether a dose-response relationship with convection volume exists, and the effects on cause-specific mortality remain unclear. The aim of this individual patient data meta-analysis was to compare the effects of haemodiafiltration and standard haemodialysis on all-cause and cause-specific mortality.

METHODS

On July 17, 2024, we searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for randomised controlled trials, published from database inception, comparing online haemodiafiltration versus haemodialysis designed to measure mortality outcomes. The primary outcome was all-cause mortality. Hazard ratios were generated using Cox proportional hazards regression models reporting hazard ratios and 95% CIs. Subgroup analyses based on predefined patient characteristics and dose-response analyses using natural splines for convection volume were performed. This analysis is registered with PROSPERO (CRD42024511514).

FINDINGS

Five trials (n=4153 patients; 2070 receiving haemodialysis and 2083 receiving haemodiafiltration) were eligible for inclusion in this analysis. After a median follow-up of 30 months (IQR 24-36), all-cause mortality occurred in 477 patients (23·3%) treated with haemodiafiltration compared with in 559 patients (27·0%) treated with haemodialysis (hazard ratio 0·84 [95% CI 0·74-0·95]). No evidence of a differential effect across subgroups was noted. A graded relationship between convection volume and mortality risk was apparent: as the volume increased, the mortality risk decreased.

INTERPRETATION

Compared with haemodialysis, online haemodiafiltration reduces all-cause mortality in people with kidney failure. Results do not differ across patient and treatment characteristics and the risk reduction appears to be dose-dependent. In conclusion, the present analysis strengthens the notion that haemodiafiltration can be considered as a superior alternative to the present standard (ie, haemodialysis).

FUNDING

European Commission Research and Innovation, Horizon 2020.

Effect of hemodiafiltration and hemodialysis on mortality of patients with end-stage kidney disease: a meta-analysis

INTRODUCTION

Previous randomized controlled trials (RCTs) and meta-analyses comparing Hemodiafiltration (HDF) with conventional hemodialysis (HD) on the effectiveness of HDF for mortality in end-stage renal disease (ESRD) patients have yielded contrasting results. Importantly, we sought to compile the available information to provide the most up-to-date and reliable evidence.

METHODS

We systematically searched PubMed, Embase and Cochrane Library for RCTs up to January 14, 2024. Review Manager 5.3 software was used to analyze relevant data and evaluate the quality of evidence.

RESULTS

Our study involved 10 randomized controlled trials with 4654 chronic dialysis patients. Compared to hemodialysis, hemodiafiltration demonstrated a reduction in all-cause mortality (relative risk [RR] 0.84, 95% confidence intervals [CI] 0.72-0.99, P = 0.04) and cardiovascular mortality (RR 0.74, 95% CI 0.61-0.90, P = 0.002). However, it did not reduce the rate of sudden death (RR 0.92, 95% CI 0.64-1.34, P = 0.68) and infection-related mortality (RR 0.70, 95% CI 0.47-1.03, P = 0.07). A subgroup analysis revealed that HDF demonstrated superiority over high-flux hemodialysis in terms of all-cause mortality, while not over low-flux hemodialysis (RR 0.81, 95% CI 0.69-0.96, P = 0.01; RR 0.93, 95% CI 0.77-1.12, P = 0.44, respectively). Furthermore, a subgroup analysis for convection volume found that hemodiafiltration with a convection volume of 22 L or more reduced all-cause and cardiovascular mortality (RR 0.76, 95% CI 0.65-0.88, P = 0.0002, RR 0.73, 95% CI 0.54-0.94, P = 0.01, respectively).

CONCLUSION

In maintenance hemodialysis patients, hemodiafiltration can reduce mortality compared to conventional hemodialysis. Furthermore, this effect is more pronounced in HDF with high convection volume.

Hemodiafiltration for children with stage 5 chronic kidney disease: technical aspects and outcomes

Despite significant medical and technical improvements in the field of dialysis, the morbidity and mortality among patients with chronic kidney disease (CKD) stage 5 on dialysis remains extremely high. Hemodiafiltration (HDF), a dialysis method that combines the two main principles of hemodialysis (HD) and hemofiltration-diffusion and convection-has had a positive impact on survival when delivered with a high convective dose. Improved outcomes with HDF have been attributed to the following factors: HDF removes middle molecular weight uremic toxins including inflammatory cytokines, increases hemodynamic stability, and reduces inflammation and oxidative stress compared to conventional HD. Two randomized trials in adults have shown improved survival with HDF compared to high-flux HD. A large prospective cohort study in children has shown that HDF attenuated the progression of cardiovascular disease, improved bone turnover and growth, reduced inflammation, and improved blood pressure control compared to conventional HD. Importantly, children on HDF reported fewer headaches, dizziness, and cramps; had increased physical activity; and improved school attendance compared to those on HD. In this educational review, we discuss the technical aspects of HDF and results from pediatric studies, comparing outcomes on HDF vs. conventional HD. Convective volume, the cornerstone of treatment with HDF and a key determinant of outcomes in adult randomized trials, is discussed in detail, including the practical aspects of achieving an optimal convective volume.

Online Hemodiafiltration: A New Perspective for Patients With End-Stage Renal Disease

Introduction Online hemodiafiltration (OL-HDF) is the most effective renal replacement therapy (RRT), which allows the enhanced removal of small and large uremic toxins by combining diffusion and convective transport of solutes. Although the goal of OL-HDF is to provide greater clearance of solutes with a preference for intermediate molecules responsible for many of the complications of chronic kidney disease (CKD), the studies reported to date and their meta-analyses are conflicting in nature and do not show a significant advantage of convective therapies on patient prognosis. Materials and methods At the Clinic of Nephrology and Dialysis, University Hospital "St. Marina", Varna, Bulgaria, 41 patients were monitored in a retrospective study for a two-year period, randomized into two groups, conducting OL-HDF after dilution and hemodialysis (HD) with the aim of studying the effect of convective therapies on the clinical outcome, the achieved quality of life, and the prognosis of the patient. Results The study found a significantly higher quality of life in patients undergoing OL-HDF with significantly higher values ​​of indicators of dialysis adequacy and nutritional status, better control of the anemic syndrome with the reduction of erythropoietin doses, significantly lower frequency of episodes of intradialytic hypotension with improved recovery, and 3.6-fold lower risk of death compared with conventional dialysis. Discussion Three major randomized controlled trials have compared survival outcomes in patients receiving HD or post-dilution OL-HDF, reporting conflicting results. Meta-analyses of the published studies have also been unable to provide a clear and definitive answer regarding the potential benefits of choosing one treatment over the other. Overall mortality, anemia, phosphate control, and small molecule clearance appear to be insufficiently influenced by the treatment method. On the other hand, cardiovascular mortality, hemodynamic stability, and clearance of middle and protein-bound molecules seem to be better in patients treated with OL-HDF. Conclusions Despite the conflicting data reported so far, OL-HDF is associated with better clinical outcome and prognosis for end-stage renal disease (ESRD) patient and undoubtedly warrants extensive future study with a view to improved quality of life in the growing dialysis population.

Hemodiafiltration versus Hemodialysis in End-Stage Kidney Disease: A Systematic Review and Meta-Analysis

Rationale & Objective

The use of hemodiafiltration (HDF) as a kidney replacement therapy (KRT) in patients with end-stage kidney disease (ESKD) has sparked a debate regarding its advantages over conventional hemodialysis (HD). The present study aims to shed light on this controversy by comparing mortality rates and cause-specific deaths between ESKD patients receiving HDF and those undergoing HD.

Study Design

Systematic review and meta-analysis of randomized controlled trials (RCTs). The search was conducted using PubMed, EMBASE, and Cochrane Central on July 1, 2023.

Setting & Participants

Adult patients with ESKD on regular KRT.

Exposure

Studies with participants undergoing HDF.

Outcomes

Primary outcomes were all-cause mortality, cardiovascular (CV) mortality, deaths related to infections, and kidney transplant. We also evaluated the endpoints for deaths related to malignancy, myocardial infarction, stroke, arrhythmias, and sudden death.

Analytical Approach

We included RCTs evaluating HDF versus HD. Crossover trials and studies with overlapping populations were excluded. Two authors independently extracted the data following predefined search criteria and quality assessment. The risk of bias was assessed with Cochrane's RoB2 tool.

Results

We included 5 RCTs with 4,143 patients, of which 2,078 (50.1%) underwent HDF, whereas 2,065 (49.8%) were receiving HD. Overall, HDF was associated with a lower risk of all-cause mortality (risk ratio [RR], 0.81; 95% confidence interval [CI], 0.73-0.91; P < 0.001; I2 = 7%) and a lower risk of CV-related deaths (RR, 0.75; 95% CI, 0.61-0.92; P = 0.007; I2 = 0%). The incidence of infection-related deaths was also significantly different between therapies (RR, 0.69; 95% CI, 0.50-0.95; P = 0.02; I2 = 26%).

Limitations

In individual studies, the HDF groups achieved varying levels of convection volume.

Conclusions

Compared with those undergoing HD, patients receiving HDF experienced a reduction in all-cause mortality, CV mortality, and infection-related mortality. These results provide compelling evidence supporting the use of HDF as a beneficial intervention in ESKD patients undergoing KRT.

Registration

Registered at PROSPERO: CRD42023438362.

Hemodialysis Procedures for Stable Incident and Prevalent Patients Optimize Hemodynamic Stability, Dialysis Dose, Electrolytes, and Fluid Balance

The demographic profile of patients transitioning from chronic kidney disease to kidney replacement therapy is changing, with a higher prevalence of aging patients with multiple comorbidities such as diabetes mellitus and heart failure. Cardiovascular disease remains the leading cause of mortality in this population, exacerbated by the cardiovascular stress imposed by the HD procedure. The first year after transitioning to hemodialysis is associated with increased risks of hospitalization and mortality, particularly within the first 90-120 days, with greater vulnerability observed among the elderly. Based on data from clinics in Fresenius Medical Care Europe, Middle East, and Africa NephroCare, this review aims to optimize hemodialysis procedures to reduce mortality risk in stable incident and prevalent patients. It addresses critical aspects such as treatment duration, frequency, choice of dialysis membrane, dialysate composition, blood and dialysate flow rates, electrolyte composition, temperature control, target weight management, dialysis adequacy, and additional protocols, with a focus on mitigating prevalent intradialytic complications, particularly intradialytic hypotension prevention.

A Historical Perspective on Uremia and Uremic Toxins

Uremia, also known as uremic syndrome, refers to the clinical symptoms in the final stage of renal failure. The definition of the term has changed over time due to an improved comprehension of the kidney's function and the advancement of dialysis technology. Here, we aim to present an overview of the various concepts that have developed regarding uremia throughout the years. We provide a comprehensive review of the historical progression starting from the early days of Kolff and his predecessors, continuing with the initial research conducted by Niwa et al., and culminating in the remote sensing hypothesis of Nigam. Additionally, we explore the subsequent investigation into the function of these toxins as signaling molecules in various somatic cells.

Hydrophilic Modification of Dialysis Membranes Sustains Middle Molecule Removal and Filtration Characteristics

While efficient removal of uremic toxins and accumulated water is pivotal for the well-being of dialysis patients, protein adsorption to the dialyzer membrane reduces the performance of a dialyzer. Hydrophilic membrane modification with polyvinylpyrrolidone (PVP) has been shown to reduce protein adsorption and to stabilize membrane permeability. In this study we compared middle molecule clearance and filtration performance of nine polysulfone-, polyethersulfone-, and cellulose-based dialyzers over time. Protein adsorption was simulated in recirculation experiments, while β2-microglobulin clearance as well as transmembrane pressure (TMP) and filtrate flow were determined over time. The results of this study showed that β2-microglobulin clearance (-7.2 mL/min/m2) and filtrate flow (-54.4 mL/min) decreased strongly during the first 30 min and slowly afterwards (-0.7 mL/min/m2 and -6.8 mL/min, respectively, for the next 30 min); the TMP increase (+37.2 mmHg and +8.6 mmHg, respectively) showed comparable kinetics. Across all tested dialyzers, the dialyzer with a hydrophilic modified membrane (FX CorAL) had the highest β2-microglobulin clearance after protein fouling and the most stable filtration characteristics. In conclusion, hydrophilic membrane modification with PVP stabilizes the removal capacity of middle molecules and filtration performance over time. Such dialyzers may have benefits during hemodiafiltration treatments which aim to achieve high exchange volumes.

Hemodiafiltration: a synergy yet to be convincing

The desperate attempt to improve mortality, morbidity, quality of life and patient-reported outcomes in patients on hemodialysis has led to multiple attempts to improve the different modes, frequencies, and durations of dialysis sessions in the last few decades. Nothing has been more appealing than the combination of diffusion and convection in the form of hemodiafiltration. Despite the concrete evidence of better clearance of middle weight molecules and better hemodynamic stability, tangible evidence to support the universal adoption is still at a distance. Survival benefits seen in selected groups who are likely to tolerate hemodiafiltration with better vascular access and with lower comorbid burden, need to be extended to real life dialysis patients who are older than the population studied and have significantly higher comorbid burden. Technical demands of initiation hemodiafiltration, the associated costs, and the incremental benefits targeted, along with patient-reported outcomes, need to be explored further before recommending hemodiafiltration as the mode of choice.

High volume online hemodiafiltration: a global perspective and the Brazilian experience

Online hemodiafiltration (HDF) is a rapidly growing dialysis modality worldwide. In Brazil, the number of patients with private health insurance undergoing HDF has exceeded the number of patients on peritoneal dialysis. The achievement of a high convection volume was associated with better clinical imprand patient - reported outcomes confirming the benefits of HDF. The HDFit trial provided relevant practical information on the implementation of online HDF in dialysis centers in Brazil. This article aims to disseminate technical information to improve the quality and safety of this new dialysis modality.

Controversy on the CONVINCE study findings: the PRO take

The CONVINCE study, recently published in the New England Journal of Medicine, reveals a groundbreaking 23% reduction in the relative risk of all-cause mortality among end-stage kidney patients undergoing high convective volume hemodiafiltration. This significant finding challenges the conventional use of high-flux hemodialysis and offers hope for improving outcomes in chronic kidney disease patients. While some controversies surround the study's findings, including concerns about generalizability and the causes of death, it is essential to acknowledge the study's design and its main outcomes. The CONVINCE study, part of the HORIZON 2020 project, enrolled 1360 patients and demonstrated the superiority of hemodiafiltration in reducing all-cause mortality overall, as well as in specific patient subgroups (elderly, short vintage, non-diabetic, and those without cardiac issues). Interestingly, it was shown that hemodiafiltration had a protective effect against infection, including COVID-19. Future research will address sustainability, dose scaling effects, identification of subgroups especially likely to benefit and cost-effectiveness. However, for now, the findings strongly support a broader adoption of hemodiafiltration in renal replacement therapy, marking a significant advancement in the field.

Impact of Albumin Leakage on the Mortality of Patients Receiving Hemodialysis or Online Hemodiafiltration

Background: Online hemodiafiltration (OHDF) has a lower mortality rate than hemodialysis (HD). We aimed to investigate the impact of the albumin leakage on the mortality of patients receiving HD or OHDF. Methods: In this single-center study, consecutive patients receiving renal replacement therapy between January and April 2018 were retrospectively registered. Using (1:1) propensity score matching, 3-year all-cause mortality was compared between patients receiving HD and OHDF, and the impact of albumin leakage on the mortality rate in both groups was investigated. Results: Of the 460 patients, 137 patients receiving HD were matched with an equal number of patients receiving OHDF. OHDF was associated with higher albumin leakage (p < 0.001) and a lower mortality than HD (log-rank test, p < 0.001). Albumin leakage was associated with mortality in patients receiving HD (per 1 g increase, hazard ratio (HR): 0.495, 95% confidence interval (CI): 0.275-0.888) and patients receiving OHDF (per 1 g increase, HR: 0.734, 95% CI: 0.588-0.915). Patients receiving HD, with the highest albumin leakage tertile (>3 g), had a similar mortality rate to patients receiving OHDF, with similar albumin leakage. Conclusions: The negative relationship between albumin leakage and mortality suggests the benefit of removing middle- to -large-molecular-weight substances to improve survival.

Effects of haemodiafiltration or haemofiltration compared with haemodialysis on prognosis in patients with end-stage renal disease: protocol an updated systematic review and meta-analysis of randomised trials with trial sequential analysis

INTRODUCTION

Haemodialysis is the most common treatment option for patients with life-sustaining end-stage kidney disease (ESKD). In recent years, haemodiafiltration or haemofiltration has been widely used in patients with ESKD, and there are still conflicting findings as to whether both are superior to traditional haemodialysis. This systematic review and meta-analysis were designed to determine whether haemodiafiltration or haemofiltration is more effective than haemodialysis in reducing all-cause mortality risk in patients with ESKD.

METHODS AND ANALYSIS

We will perform a systematic PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library and Scopus search, including studies published before September 2023. Randomised controlled trials will be included exploring the effects of haemodiafiltration or haemofiltration compared with haemodialysis on prognosis in patients with ESKD. Outcomes of interest include all-cause mortality, cardiovascular events, dialysis adequacy and adverse effects. The Cochrane Collaboration tools (ROB-2) will assess the bias risk. Available data will be used to calculate effect sizes. Heterogeneity between studies will be evaluated with I2. The trial sequential analysis will be used to eliminate false-positive results. The certainty of the evidence will be assessed using Grading of Recommendations, Assessment, Development and Evaluation criteria.

ETHICS AND DISSEMINATION

This systematic review and meta-analysis was deemed exempt from ethics review. Results will be disseminated through publication in peer-reviewed journals and research conferences.

PROSPERO REGISTRATION NUMBER

CRD42023464509.

ABCs of hemodiafiltration prescription: The Pisa style

In end-stage kidney disease patients, hemodiafiltration, a mixed diffusive-convective technique, has shown beneficial effects in terms of improvement of anemia, inflammation, mineral bone disorders, malnutrition and cardiovascular stability. Greater convective volume exchange was also associated with improved overall and cardiovascular survival. However, absolute target threshold volume would be difficult to define and achieve in daily clinical practice, mainly because of differences in patient size. Convective volumes standardized for body surface area would appear to be the simplest approach in clinical practice. Several factors can affect achievement of optimal convective volume, with vascular access being the main limiting factor. Based on our own clinical experience, hemodiafiltration is a more effective and preferable dialysis technique but only when a target convective volume greater than 20 L can be achieved. Conversely, standard high flux hemodialysis or expanded hemodialysis may be helpful and valuable alternative dialysis techniques.

Comparison of the pre-dilution and post-dilution methods for online hemodiafiltration

Online hemodiafiltration (OL-HDF) is a treatment modality using diffusion and ultrafiltration. There are two types of dilution methods in OL-HDF: pre-dilution, which is commonly provided in Japan, and post-dilution, which is commonly provided in Europe. The optimal OL-HDF method for individual patients is not well studied. In this study, we compared the clinical symptoms, laboratory data, spent dialysate, and adverse events of pre- and post-dilution OL-HDF. We conducted a prospective study of 20 patients who underwent OL-HDF between January 1, 2019 and October 30, 2019. Their clinical symptoms and dialysis efficacy were evaluated. All patients underwent OL-HDF every 3 months in the following sequence: first pre-dilution, post-dilution, and second pre-dilution. We evaluated 18 patients for the clinical study and 6 for the spent dialysate study. No significant differences in spent dialysates regarding small and large solutes, blood pressure, recovery time, and clinical symptoms were observed between the pre- and post-dilution methods. However, the serum α1-microglobulin level in post-dilution OL-HDF was lower than that in pre-dilution OL-HDF (first pre-dilution: 124.8 ± 14.3 mg/L; post-dilution: 116.6 ± 13.9 mg/L; second pre-dilution: 125.8 ± 13.0 mg/L; first pre-dilution vs. post-dilution, post-dilution vs. second pre-dilution, and first pre-dilution vs. second pre-dilution: p = 0.001, p < 0.001, and p = 1.000, respectively). The most common adverse event was an increase in transmembrane pressure in the post-dilution period. Compared to pre-dilution, the post-dilution method decreased the α1-microglobulin level; however, there were no significant differences in clinical symptoms or laboratory data.

Japanese Study of the Effects of AMG (α1-Microglobulin) Reduction Rates on Survival (JAMREDS): A Protocol of a Multicenter Prospective Observational Cohort Study

INTRODUCTION

Recent advances in dialysis therapy have made it possible to remove middle molecules. Removal of small-middle molecules, such as β2-microglobulin, can now be achieved with conventional hemodialysis (HD), and removal of large-middle molecules has become a target, particularly for α1-microglobulin (AMG, 33 kD). The AMG reduction rate has emerged as a target for improvement of various clinical symptoms, but the effects on prognosis have yet to be determined. The "Japanese study of the effects of AMG (α1-microglobulin) reduction rates on survival" (JAMREDS) was started in April 2020, with the goal of determining if the AMG reduction rate associates with the risk of mortality and cardiovascular disease (CVD) events.

METHODS

JAMREDS is a prospective observational study in patients on HD to examine the effects of: (1) AMG reduction rate on survival outcome and CVD events; (2) dialysis treatment modalities (HD, intermittent infusion hemodiafiltration(iHDF), pre/post-dilution online HDF) on survival and CVD events (based on AMG reduction rates with treatment mode); and (3) AMG reduction rates on survival and CVD events in patients undergoing each therapy (iHDF, pre/post-dilution online HDF). The number of planned subjects was 4,000 in preplanning. Data are collected using RED-Cap, which is an EDC system. A total of 9,930 patients were enrolled at the beginning of the study at 59 registered facilities. The JAMREDS observation period will continue until the end of 2023, after which the data will be cleaned and confirmed before analysis.

CONCLUSION

This study may provide new evidence for the relationship between the amount of removed large-middle molecules (such as AMG) and the mortality and CVD risk. Comparisons with convection volumes will also be of interest.

Middle Molecular Uremic Toxin and Blood Purification Therapy

The purpose of blood purification therapy is to remove uremic toxins, and middle molecules (MMs) are a specific target. An MM is defined as a solute that passes through the glomerulus with a molecular weight in the range of 0.5-58 kDa, and new classifications of "small-middle 0.5-15 kDa," "medium-middle 15-25 kDa," and "large-middle 25-58 kDa" were proposed. In Japan, the removal of α1-microglobulin (αMG) in the large-middle range has been the focus, but a new theory of removal has been developed, emphasizing the antioxidant effect of αMG as a physiological function. Clinical proof of this mechanism will lead to further development of blood purification therapies.

Comparing Survival Outcomes between Hemodialysis and Hemodiafiltration Using Real-World Data from Brazil

The CONVINCE trial demonstrates that high-dose hemodiafiltration offers a survival advantage for patients in the high-flux hemodiafiltration group compared to hemodialysis. We compared the outcomes of hemodialysis and hemodiafiltration using real-world data. We conducted an analysis on a cohort of patients who underwent hemodiafiltration therapy (HDF) at a single center, NefroStar Clinics. The results obtained were then compared with data from patients receiving hemodialysis (HD) therapy within the Brazilian Public Health System (SUS). The primary outcome was mortality from any cause. Results: A total of 85 patients undergoing hemodiafiltration were compared with 149,372 patients receiving hemodialysis through the Brazilian Public Health System (SUS). Using a 2:1 propensity score, we compared the 170 best-match HD patients with 85 HDF patients. In the Cox analysis, HDF therapy showed a reduced risk of mortality with an HR of 0.29 [0.11-0.77]. The propensity score analysis showed a HR of 0.32 [95% CI: 0.11-0.91]. This analysis was adjusted for age, type of access, KT/v, hemoglobin, and phosphorus. The Kaplan-Meier analysis showed respective survival rates for HDF and HD at the end of one year, 92.1% and 79.9%, p < 0.001. These results suggest high-flux hemodiafiltration has survival advantages over hemodialysis in a real-world scenario.

The role of intra- and interdialytic sodium balance and restriction in dialysis therapies

The relationship between sodium, blood pressure and extracellular volume could not be more pronounced or complex than in a dialysis patient. We review the patients' sources of sodium exposure in the form of dietary salt intake, medication administration, and the dialysis treatment itself. In addition, the roles dialysis modalities, hemodialysis types, and dialysis fluid sodium concentration have on blood pressure, intradialytic symptoms, and interdialytic weight gain affect patient outcomes are discussed. We review whether sodium restriction (reduced salt intake), alteration in dialysis fluid sodium concentration and the different dialysis types have any impact on blood pressure, intradialytic symptoms, and interdialytic weight gain.

Removal performance of pre- and post-dilution online hemodiafiltration using identical hemodiafilters in the same patients

Online hemodiafiltration (OHDF) for renal replacement therapy has two modes: pre- (pre-OHDF) and post-dilution OHDF (post-OHDF). To elucidate the precise differences between the two modes, a clinical study was performed using the same polysulfone hemodiafilters in the same patients. Eight patients were treated with ABH™-22PA for 6 weeks: 3 weeks of pre-OHDF (with substitution volumes of 24, 36, and 48 L) and 3 weeks of post-OHDF (6, 8, and 10 L). The reduction ratios of urea, uric acid (UA), creatinine (CRE), inorganic phosphorus (iP), beta-2-microglobulin (β2-MG), and alpha-1-microglobulin (α1-MG) were evaluated. The removal amounts of β2-MG, α1-MG, and albumin were also evaluated by analyzing the spent dialysis fluids. The types and numbers of adverse events (AEs) and device malfunctions were recorded. The reduction ratios of urea, UA, CRE, iP, and β2-MG were comparable among all conditions, while that of α1-MG tended to be slightly higher in post-OHDF than in pre-OHDF. The removal amounts of α1-MG and albumin in pre-OHDF and post-OHDF were significantly greater with the maximum substitution volume than with the minimum volume. However, the selective removal indices, which were obtained by dividing the amount of α1-MG removed by the albumin level, tended to be slightly higher in pre- than in post-OHDF. No device-related AEs or device malfunctions occurred in either mode. No significant differences in inflammatory responses, evaluated by high-sensitivity C-reactive protein and interleukin-6, were observed. This study provides removal performance and safety data regarding the application of ABH-22PA for pre- and post-OHDF.

High-Target Hemodiafiltration Convective Dose Achieved in Most Patients in a 6-Month Intermediary Analysis of the CONVINCE Randomized Controlled Trial

Introduction

High convection volumes in hemodiafiltration (HDF) result in improved survival; however, it remains unclear whether it is achievable in all patients.

Methods

CONVINCE, a randomized controlled trial, randomized patients with end-stage kidney disease 1:1 to high-dose HDF versus high-flux hemodialysis (HD) continuation. We evaluated the proportion of patients achieving high-dose HDF target: convection volume per visit of ≥23 l (range ±1 l) at baseline, month 3, and month 6. We compared baseline characteristics in the following 2 ways: (i) patients on target for all 3 visits versus patients who missed target on ≥1 visits and (ii) patients on target for all 3 visits or missing it once versus patients who missed target on ≥2 visits.

Results

A total of 653 patients were randomized to HDF. Their mean age was 62.2 (SD 13.5) years, 36% were female, 81% had fistula vascular access, and 33% had diabetes. Across the 3 visits, 75 patients (11%), 27 patients (4%), and 11 patients (2%) missed the convection volume target once, twice, and thrice, respectively. Apart from diabetes, there were no apparent differences in patient characteristics between patients who always achieved the high-dose target (83%) and those who missed the target either once or more (17%) or twice or more (6%).

Conclusion

Achieving high-dose HDF is feasible for nearly all patients in CONVINCE and could be maintained during the 6-month follow-up period. Apart from diabetes, there were no other indications for confounding by indication on multivariable analyses that may explain the potential survival advantage for patients receiving high-dose HDF.

Comparison of the medium cutoff dialyzer and postdilution hemodiafiltration on the removal of small and middle molecule uremic toxins

BACKGROUND

The medium cutoff (MCO) dialyzer increases the removal of several middle molecules more effectively than high-flux hemodialysis (HD). However, comparative data addressing the efficacy and safety of MCO dialyzers vs. postdilution hemodiafiltration (HDF) in Korean patients are lacking.

METHODS

Nine patients with chronic HD were included in this pre-post study. Patients underwent HD with an MCO dialyzer for 4 weeks, followed by a 2-week washout period using a high-flux dialyzer to minimize carryover effects, and then turned over to postdilution HDF for 4 weeks. Reduction ratios and differences in the uremic toxins before and after dialysis were calculated from the MCO dialysis, postdilution HDF, and high-flux HD. In the in vitro study, EA.hy926 cells were incubated with dialyzed serum.

RESULTS

Compared to postdilution HDF, the MCO dialyzer achieved significantly higher reduction ratios for larger middle molecules (myoglobin, kappa free light chain [κFLC], and lambda FLC [λFLC]). Similarly, the differences in myoglobin, κFLC, and λFLC concentrations before and after the last dialysis session were significantly greater in MCO dialysis than in postdilution HDF. The expression of Bax and nuclear factor κB was decreased in the serum after dialysis with the MCO dialyzer than with HDF.

CONCLUSION

Compared with high-volume postdilution HDF, MCO dialysis did not provide greater removal of molecules below 12,000 Da, whereas it was superior in the removal of larger uremic middle molecule toxins in patients with kidney failure. Moreover, these results may be expected to have an anti-apoptotic effect on the human endothelium.

Long-term peridialytic blood pressure changes are related to mortality

BACKGROUND

In chronic haemodialysis (HD) patients, the relationship between long-term peridialytic blood pressure (BP) changes and mortality has not been investigated.

METHODS

To evaluate whether long-term changes in peridialytic BP are related to mortality and whether treatment with HD or haemodiafiltration (HDF) differs in this respect, the combined individual participant data of three randomized controlled trials comparing HD with HDF were used. Time-varying Cox regression and joint models were applied.

RESULTS

During a median follow-up of 2.94 years, 609 of 2011 patients died. As for pre-dialytic systolic BP (pre-SBP), a severe decline (≥21 mmHg) in the preceding 6 months was independently related to increased mortality [hazard ratio (HR) 1.61, P = .01] when compared with a moderate increase. Likewise, a severe decline in post-dialytic diastolic BP (DBP) was associated with increased mortality (adjusted HR 1.96, P < .0005). In contrast, joint models showed that every 5-mmHg increase in pre-SBP and post-DBP during total follow-up was related to reduced mortality (adjusted HR 0.97, P = .01 and 0.94, P = .03, respectively). No interaction was observed between BP changes and treatment modality.

CONCLUSION

Severe declines in pre-SBP and post-DBP in the preceding 6 months were independently related to mortality. Therefore peridialytic BP values should be interpreted in the context of their changes and not solely as an absolute value.

Unveiling the Clinical Benefits of High-Volume Hemodiafiltration: Optimizing the Removal of Medium-Weight Uremic Toxins and Beyond

Dialysis treatment has improved the survival of patients with kidney failure. However, the hospitalization and mortality rates remain alarmingly high, primarily due to incomplete uremic toxin elimination. High-volume hemodiafiltration (HDF) has emerged as a promising approach that significantly improves patient outcomes by effectively eliminating medium and large uremic toxins, which explains its increasing adoption, particularly in Europe and Japan. Interest in this therapy has grown following the findings of the recently published CONVINCE study, as well as the need to understand the mechanisms behind the benefits. This comprehensive review aims to enhance the scientific understanding by explaining the underlying physiological mechanisms that contribute to the positive effects of HDF in terms of short-term benefits, like hemodynamic tolerance and cardiovascular disease. Additionally, it explores the rationale behind the medium-term clinical benefits, including phosphorus removal, the modulation of inflammation and oxidative stress, anemia management, immune response modulation, nutritional effects, the mitigation of bone disorders, neuropathy relief, and amyloidosis reduction. This review also analyzes the impact of HDF on patient-reported outcomes and mortality. Considering the importance of applying personalized uremic toxin removal strategies tailored to the unique needs of each patient, high-volume HDF appears to be the most effective treatment to date for patients with renal failure. This justifies the need to prioritize its application in clinical practice, initially focusing on the groups with the greatest potential benefits and subsequently extending its use to a larger number of patients.

Effect of Hemodiafiltration or Hemodialysis on Mortality in Kidney Failure

BACKGROUND

Several studies have suggested that patients with kidney failure may benefit from high-dose hemodiafiltration as compared with standard hemodialysis. However, given the limitations of the various published studies, additional data are needed.

METHODS

We conducted a pragmatic, multinational, randomized, controlled trial involving patients with kidney failure who had received high-flux hemodialysis for at least 3 months. All the patients were deemed to be candidates for a convection volume of at least 23 liters per session (as required for high-dose hemodiafiltration) and were able to complete patient-reported outcome assessments. The patients were assigned to receive high-dose hemodiafiltration or continuation of conventional high-flux hemodialysis. The primary outcome was death from any cause. Key secondary outcomes were cause-specific death, a composite of fatal or nonfatal cardiovascular events, kidney transplantation, and recurrent all-cause or infection-related hospitalizations.

RESULTS

A total of 1360 patients underwent randomization: 683 to receive high-dose hemodiafiltration and 677 to receive high-flux hemodialysis. The median follow-up was 30 months (interquartile range, 27 to 38). The mean convection volume during the trial in the hemodiafiltration group was 25.3 liters per session. Death from any cause occurred in 118 patients (17.3%) in the hemodiafiltration group and in 148 patients (21.9%) in the hemodialysis group (hazard ratio, 0.77; 95% confidence interval, 0.65 to 0.93).

CONCLUSIONS

In patients with kidney failure resulting in kidney-replacement therapy, the use of high-dose hemodiafiltration resulted in a lower risk of death from any cause than conventional high-flux hemodialysis. (Funded by the European Commission Research and Innovation; CONVINCE Dutch Trial Register number, NTR7138.).

Improved β2-Microglobulin and Phosphorous Removal with Expanded Hemodialysis and Online Hemodiafiltration versus High-Flux Hemodialysis: A Cross-Over Randomized Clinical Trial

INTRODUCTION

Expanded hemodialysis (HDx) is expected to provide enhanced permeability of medium-sized molecules, selective solute retention, and better internal retrofiltration. The primary objective of this study was to compare the efficiency for removal of β2-microglobulin with 3 different extracorporeal therapies (ETs): high-flux hemodialysis (HF), online hemodiafiltration (OL-HDF), and HDx. The secondary objective was to evaluate the efficiency of removal of other uremic toxins, including urea, phosphate, CRP, IL-6, IL-10, TNF-⍺, indoxyl sulfate, and p-cresol.

METHODS

This single-center, randomized, and cross-over study was performed. Patients were randomized to determine the initial modality of treatment, each period lasted 4 weeks and between one modality and another, there was a washout period of 1 week. Reduction ratios (RRs) of different-size molecules and albumin were calculated for the different ET.

RESULTS

Twenty-two patients were included, β2-microglobulin RR was greater during both OL-HDF and HDx as compared to HF (RR 62% vs. 73% vs. 27%, respectively, p = <0.0001), and there was no significant difference between HDx and OL-HDF (p = 0.09). A decrease in serum phosphate levels was observed in the HDx and OL-HDF periods, contrary to an increase in HF (-0.79 mg/dL vs. -1.02 mg/dL vs. + 0.11 mg/dL, respectively, p = <0.0001). There was no difference in RRs of other molecules (BUN, CRP, IL-6, IL-10, TNF-⍺, indoxyl sulfate, and p-Cresol). There was no decrease in serum albumin in any ET.

CONCLUSION

HDx provides enhanced removal of β2-microglobulin and phosphate as compared to HF, and similar efficacy as with OL-HDF. HDx should be considered an alternative to chronic convective therapies.

Management of Cardiovascular Diseases in Chronic Hemodialysis Patients

Hemodialysis (HD) is the main treatment modality for patients with end-stage kidney disease. Cardiovascular diseases (CVD) are highly prevalent in HD patients and are the leading cause of death in this population, with the mortality from CVD approximately 20 times higher than that of the general population. Traditional and non-traditional cardiovascular risk factors accelerate progression of CVD and exacerbate the prognosis in HD patients. This review provides a brief overview of the characteristics of CVD in HD patients, and a description of advances in its management.

Advances in hemodialysis therapy

End-stage renal disease (ESRD) continues to be a disease process with a high rate of hospitalization and mortality. There has been little innovation in nephrology over the last few decades compared to revolutionary high-tech advancements in other areas like oncology and cardiovascular medicine. Kidney transplantation, the only available alternative to renal replacement therapy, is limited in its availability. It is essential to have advances in this field to improve the efficiency of currently available treatments and devise new therapies. The current description of renal replacement therapy is inappropriate as it only replaces the filtration function of the failed kidney without addressing its other vital metabolic, endocrinologic, and immunologic roles and portability. Hence, it is critical to have newer therapies focusing on total replacement and portability, not just clearance. This review will address the developments in hemodialysis therapy. Advances in hemodialysis therapy include hemodiafiltration, portable machines, wearable artificial kidneys, and bioartificial kidneys. Although promising, newer technologies in this direction are still far from clinical application. Several organizations and enterprises including the Kidney Health Initiative and Kidney X: The Kidney Innovation Accelerator, as well as The Advancing American Kidney Health Initiative, are working in tandem to develop new therapies that could customize the treatment of ESRD.

A Spontaneous Bilateral Quadriceps Tendon Rupture in a Patient Undergoing Long-Term Hemodialysis

Spontaneous quadriceps tendon rupture is very rare. Its occurrence is usually linked to an underlying disease that weakens the tendons causing them to rupture. Here, we report the case of a 44-year-old patient undergoing long-term hemodialysis who had spontaneous bilateral quadriceps tendon rupture. We present the clinical presentation and the management of this injury.

Systematic Comparison of Uremic Toxin Removal Using Different Hemodialysis Modes: A Single-Center Crossover Prospective Observational Study

Many hypotheses could explain the mortality decrease observed using hemodiafiltration, such as reduction of intradialytic hypotension and more efficient toxin removal. We led a systematic analysis of representative uremic toxin removal with hemodialysis (HD), online postdilution hemodiafiltration (postHDF) and online predilution hemodiafiltration (preHDF), in a single-center crossover and prospective observational study. The primary outcome was the reduction ratio of uremic toxins of the three categories defined by the Eutox group. Twenty-six patients were treated by those three techniques of extra renal epuration. Mean Kt/Vurea was not different between the treatment methods. Mean reduction ratio of beta2microglobulin was significantly higher for both HDF treatments than for HD (p < 0.001). Myoglobin, kappa, and lambda free light chain reduction ratio was significantly different between the modes: 37.75 ± 11.95%, 45.31 ± 11% and 61.22 ± 10.56%/57.21 ± 12.5%, 63.53 ± 7.93%, and 68.40 ± 11.79%/29.12 ± 8.44%, 34.73 ± 9.01%, and 45.55 ± 12.31% HD, preHDF, and postHDF, respectively (p < 0.001). Mean protein-bound solutes reduction ratio was not different between the different treatments except for PCS with a higher reduction ratio during HDF treatments. Mean albumin loss was always less than 2 g. HDF improved removal of middle molecules but had no effect on indoles concentration without any difference between synthetic dialysis membranes.

Hemodiafiltration: Technical and Medical Insights

Despite the significant medical and technical improvements in the field of dialytic renal replacement modalities, morbidity and mortality are excessively high among patients with end-stage kidney disease, and most interventional studies yielded disappointing results. Hemodiafiltration, a dialysis method that was implemented in clinics many years ago and that combines the two main principles of hemodialysis and hemofiltration-diffusion and convection-has had a positive impact on mortality rates, especially when delivered in a high-volume mode as a surrogate for a high convective dose. The achievement of high substitution volumes during dialysis treatments does not only depend on patient characteristics but also on the dialyzer (membrane) and the adequately equipped hemodiafiltration machine. The present review article summarizes the technical aspects of online hemodiafiltration and discusses present and ongoing clinical studies with regards to hard clinical and patient-reported outcomes.

Impact of needle type on substitution volume during online hemodiafiltration: plastic cannulae versus metal needles

BACKGROUND

Plastic cannulae have attracted increasing interest as an alternative to traditional metal needles with the aim of reducing cannulation-related complications. We investigated whether the substitution volumes during hemodiafiltration differ using these two types of needles in dialysis patients.

METHODS

An intervention study involving 26 hemodialysis patients was conducted in Korea between March and September in 2021. Patients first received online hemodiafiltration using traditional metal needles, and thereafter plastic cannulae were used in a stepwise protocol. Repeated-measures design and linear mixed-effect models were used to compare substitution volumes between the two needle types with the same inner diameter.

RESULTS

The mean patient age was 62.7 years, and their mean dialysis vintage was 95.2 months. Most patients (92.3%) had an arteriovenous fistula as the vascular access. The substitution volume increased as blood flow and needle size increased for both plastic cannulae and metal needles. The substitution volume was significantly higher with 17-gauge (G) plastic cannulae than with 16-G metal needles at blood flow rates of 280, 300, and 330 mL/min. Similar results were obtained for 15-G metal needles and 16-G plastic cannulae at a blood flow rate of 330 mL/min. However, the patient ratings of pain on a visual analogue scale were higher for plastic cannulae.

CONCLUSION

Higher substitution volumes were obtained at the same prescribed blood flow rate with plastic cannulae than with metal needles during online hemodiafiltration. Plastic cannulae are an option for achieving high-volume hemodiafiltration for patients with low blood flow rates.

Middle-size molecule clearance as measured by β2-microglobulin in high-flux versus low-flux dialysis and hemodiafiltration: A prospective randomized controlled trial

BACKGROUND

Whereas most studies to date have mainly concentrated on the comparison between high-flux hemodialysis (HFHD) and hemodiafiltration (HDF), or HFHD and low-flux hemodialysis (LFHD) in relation to the clearance of β2-microglobulin (β2M) in HD patients, there have been few related to combined HFHD and HDF therapy. To compare the clearance of middle-sized molecules as measured by β2M in HFHD versus LFHD and HDF.

METHODS

A prospective, single-center, open-label, observer-blinded, randomized controlled trial was conducted at the West China Hospital of Sichuan University in China. Patients received either HFHD or LFHD and HDF 3 times a week with follow-ups at one and 3 months. The primary endpoint was the clearance of β2M at 3 months. The secondary endpoints included hemodialysis-related adverse events, changes in anemia, states of nutrition, and inflammatory indices.

RESULTS

After 3 months of treatment, the HFHD+HDF group achieved a higher satisfaction level than the LFHD+HDF group, with decreased serum β2M concentrations (34.493 ± 7.257 vs. 43.593 ± 9.036 mg/L, p < 0.001) and elevated red blood cell counts (3.959 ± 0.742 vs. 3.602 ± 0.578 × 10¹² /L, p = 0.015). Compared with baseline, both kinds of treatment led to increases in serum urea (t = -3.623, p = 0.001 vs. t = -4.240, p < 0.001), cholesterol (t = -2.511, p = 0.016 vs. t = -4.472, p < 0.001), and magnesium (t = -2.648, p = 0.011 vs. t = -3.561, p = 0.001). An elevated level of serum albumin (t = -2.683, p = 0.010) was observed only in the HFHD+HDF group.

CONCLUSIONS

Combined therapy with HFHD and HDF has a beneficial effect on improving β2M clearance, red blood cell management, and nutrition status in HD patients.

Nutritional and Anthropometric Indices in Children Receiving Haemodiafiltration vs Conventional Haemodialysis - The HDF, Heart and Height (3H) Study

BACKGROUND

The "HDF-Heart-Height" study showed that haemodiafiltration (HDF) is associated with improved growth compared to conventional haemodialysis (HD). We report a post-hoc analysis of this study assessing the effect of extracorporeal dialysis therapies on nutritional indices.

METHODS

107 children were included in the baseline cross-sectional analysis, of whom 79 (43 HD, 36 HDF) completed the 12-month follow-up. Height (Ht), optimal 'dry' weight (Wt), and body mass index (BMI) standard deviations scores (SDS), waist-to-hip ratio, des-acyl ghrelin (DAG), adiponectin, leptin, insulin-like growth factor-1 (IGF-1)-SDS and insulin were measured.

RESULTS

The levels of nutritional indices were comparable between HDF and HD patients at baseline and 12-month. On univariable analyses Wt-SDS positively correlated with leptin and IGF-1-SDS, and negatively with DAG, while Ht-SDS of the overall cohort positively correlated with IGF1-SDS and inversely with DAG and adiponectin. On multivariable analyses, higher 12-month Ht-SDS was inversely associated with baseline DAG (beta = -0.13 per 500 higher; 95%CI -0.22, -0.04; P = .004). Higher Wt-SDS at 12-month was positively associated with HDF modality (beta = 0.47 vs HD; 95%CI 0.12-0.83; P = .01) and inversely with baseline DAG (beta = -0.18 per 500 higher; 95%CI -0.32, -0.05; P = .006). Growth Hormone (GH) treated patients receiving HDF had higher annualized increase in Ht SDS compared to those on HD.

CONCLUSIONS

In children on HD and HDF both Wt- and Ht-SDS independently correlated with lower baseline levels of the anorexygenic hormone DAG. HDF may attenuate the resistance to GH, but further studies are required to examine the mechanisms linking HDF to improved growth.

Anti-Inflammatory Approach in Chronic Dialysis Patients with SARS-CoV-2: ATA or PMMA Dialyzers?

INTRODUCTION

High-flux hemodialysis membranes may modulate the cytokine storm of SARS-CoV-2, but their impact on chronic hemodialysis (CHD) patients is unknown. The aim of the study was the evaluation of asymmetric cellulose triacetate (ATA) and polymethylmethacrylate (PMMA) dialyzers on inflammatory markers and clinical outcomes in CHD patients with SARS-CoV-2.

METHODS

A prospective, observational study on CHD patients with SARS-CoV-2 was carried out. Patients were enrolled from March 2020 to May 2021. Pre- and postdialysis C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) were determined at each session. Patients who underwent on-line hemodiafiltration (OLHDF) with a PMMA dialyzer were compared with those treated with OLHDF with a ATA dialyzer. The primary endpoint was the differences in the reduction ratio per session (RR) of CRP, PCT, IL-6, and IL-6 RR >25%.

RESULTS

We consecutively enrolled 74 CHD patients with COVID-19, 48 were treated with ATA membrane, and 26 with PMMA. Median IL-6 RR was higher in the ATA group compared to PMMA (17.08%, IQR -9.0 to 40.0 vs. 2.95%, IQR -34.63 to 27.32). Median CRP RR was 7.77% (IQR 2.47-13.77) in the ATA group versus 4.8% (IQR -2.65 to 11.38) in the PMMA group (p = 0.0017). Median PCT-RR% was 77.38% (IQR 70.92-82.97) in ATA group versus 54.59% (IQR 42.62-63.16) in the PMMA group (p < 0.0001). A multiple logistic regression analysis with IL-6 RR >25% as the outcome including the membrane employed, pre-dialysis IL-6, CRP, PCT, and ferritin showed that ATA led to a higher probability to reach the outcome (OR 1.891, 95% CI 1.273-2.840, p = 0.0018) while higher CRP favors the risk of lower IL-6 RR values (OR 0.910, 95% CI 0.868-0.949, p ≤ 0.0001).

CONCLUSIONS

In SARS-CoV-2 CHD patients treated with OLHDF, ATA showed a better anti-inflammatory profile, regarding IL-6 RR, compared to PMMA.

Why should we focus on high-volume hemodiafiltration?

Though noticeable technological advances related to hemodialysis (HD) have been made, unfortunately, the survival rate of dialysis patients has yet to improve significantly. However, recent research findings reveal that online hemodiafiltration (HDF) significantly improves patient survival in comparison to conventional HD. Accordingly, the number of patients receiving online HDF is increasing. Although the mechanism driving the benefit has not yet been fully elucidated, survival advantages are mainly related to the lowering of cardiovascular mortality. High cardiovascular mortality among HD patients is seemingly attributable to the cardiovascular changes that occur in response to renal dysfunction and the HD-induced myocardial stress and injury, and online HDF appears to improve such secondary cardiovascular changes. Interestingly, patient survival improves only if the convection volume is supplied sufficiently over a certain level during online HDF treatment. In other words, survival improvement from online HDF is related to convection volume. Therefore, there is a growing interest in high-volume HDF in terms of improving the survival rate. The survival improvement will require a minimum convection volume of 23 L or more per 4-hour session for postdilution HDF. To obtain an optimal high convection volume in online HDF, several factors, such as the treatment time, blood flow rate, filtration fraction, and dialyzer, need to be considered. High-volume HDF can be performed easily and safely in routine clinical practice. Therefore, when the required equipment is available, performing high-volume HDF will help to improve the survival rate of dialysis patients.

Effects of high albumin leakage on survival between online hemodiafiltration and super high-flux hemodialysis: the HISTORY study

Background

All-cause mortality is lower with a high substitution volume in predilution (pre) and postdilution (post) online hemodiafiltration (OHDF) than with hemodialysis (HD), and mortality does not significantly differ between pre- and post-OHDF groups. Despite the improved survival with a high substitution volume, there may be limitations. On the other hand, either normoalbuminemia or high albumin leakage in HD can reduce mortality, and super high-flux (SHF) membrane dialyzers can reduce mortality compared with low-flux and high-flux membrane dialyzers. Here, we investigated the associations of serum albumin concentration (s-Alb), albumin leakage, and substitution volume with all-cause mortality in OHDF and SHF-HD.

Methods

In a 3-year retrospective observational study of patients receiving dialysis from April 1 to July 1, 2017, we developed a propensity score-matched model using 783 stable patients (SHF-HD, 355; OHDF, 428). We used the log-rank test to compare Kaplan–Meier survival curves and Cox regression analysis to calculate hazard ratio (HR). Cox regression analysis was also used to compare the effect of estimated albumin leakage (EAL) and substitution volume on 3-year all-cause mortality.

Results

All-cause mortality was significantly lower with high EAL than with low EAL (SHF-HD: P = 0.012, log-rank test; HR, 0.44; 95% confidence interval [CI] 0.23–0.85; OHDF: P = 0.027, log-rank test; HR, 0.41; 95% CI 0.18–0.93). The mortality of high EAL was not significantly different between high and low s-Alb in SHF-HD (3.5 ± 0.1 and 3.2 ± 0.2 g/dL) and OHDF (3.6 ± 0.2 and 3.2 ± 0.1 g/dL), despite significant differences in s-Alb. Mortality did not significantly differ between SHF-HD and OHDF with higher EAL ranges or a lower difference in EAL. Mortality in pre-OHDF was significantly correlated with EAL (P = 0.007, beta − 0.32) rather than substitution volume, and mortality in post-OHDF was not analyzed because of fewer deaths.

Conclusions

The results suggest that survival is improved more with high EAL than with low EAL in both OHDF and SHF-HD patients, that high EAL with mild-to-moderate hypoalbuminemia does not necessarily worsen survival in OHDF and SHF-HD patients, and that survival is equivalent between OHDF and SHF-HD patients with a similar level of EAL.

Water-Soluble Vitamins and Trace Elements Losses during On-Line Hemodiafiltration

Maintenance hemodialysis induces water-soluble vitamins and trace elements losses, which is why recommendations regarding potential supplementation were provided, but mainly based on conventional hemodialysis. This study′s aim was to measure the water–soluble vitamins and trace element losses during one on-line post-dilution hemodiafiltration (HDF) session. Thirty-nine patients under maintenance HDF were enrolled. We used the Theraflux^® sampler (Theradial Corp., Orvault, France) to analyze the full session dialysate mass transfer. Blood and dialysate samples were collected before and after one HDF session to measure B1, B2, B6, B9, B12, C vitamins, zinc, and selenium concentrations. Values significantly decreased for B1 (20.2%), B2 (13%), B6 (25.4%), B9 (32.6%), C (66.6%) and selenium (6.7%). No significant differences were found for vitamin B12 and zinc. The dialysate losses per session were 1.12 ± 0.88 mg for vitamin B1, 0.28 ± 0.30 mg for B2, 0.33 ± 0.09 mg for B6, 0.3 ± 0.18 mg for B9, 147.5 ± 145.50 mg for C and 25.75 ± 6.91 mg for zinc. Vitamin B12 and selenium were under detection values. In conclusion, during a standard 4hr-HDF session, we found important losses for vitamin B1, B6, B9, C and zinc, suggesting the need for regular monitoring of plasma levels and systematic supplementation of these compounds.

The high-volume haemodiafiltration vs high-flux haemodialysis registry trial (H4RT): a multi-centre, unblinded, randomised, parallel-group, superiority study to compare the effectiveness and cost-effectiveness of high-volume haemodiafiltration and high-flux haemodialysis in people with kidney failure on maintenance dialysis using linkage to routine healthcare databases for outcomes

BACKGROUND

More than a third of the 65,000 people living with kidney failure in the UK attend a dialysis unit 2-5 times a week to have their blood cleaned for 3-5 h. In haemodialysis (HD), toxins are removed by diffusion, which can be enhanced using a high-flux dialyser. This can be augmented with convection, as occurs in haemodiafiltration (HDF), and improved outcomes have been reported in people who are able to achieve high volumes of convection. This study compares the clinical- and cost-effectiveness of high-volume HDF compared with high-flux HD in the treatment of kidney failure.

METHODS

This is a UK-based, multi-centre, non-blinded randomised controlled trial. Adult patients already receiving HD or HDF will be randomised 1:1 to high-volume HDF (aiming for 21+ L of substitution fluid adjusted for body surface area) or high-flux HD. Exclusion criteria include lack of capacity to consent, life expectancy less than 3 months, on HD/HDF for less than 4 weeks, planned living kidney donor transplant or home dialysis scheduled within 3 months, prior intolerance of HDF and not suitable for high-volume HDF for other clinical reasons. The primary outcome is a composite of non-cancer mortality or hospital admission with a cardiovascular event or infection during follow-up (minimum 32 months, maximum 91 months) determined from routine data. Secondary outcomes include all-cause mortality, cardiovascular- and infection-related morbidity and mortality, health-related quality of life, cost-effectiveness and environmental impact. Baseline data will be collected by research personnel on-site. Follow-up data will be collected by linkage to routine healthcare databases - Hospital Episode Statistics, Civil Registration, Public Health England and the UK Renal Registry (UKRR) in England, and equivalent databases in Scotland and Wales, as necessary - and centrally administered patient-completed questionnaires. In addition, research personnel on-site will monitor for adverse events and collect data on adherence to the protocol (monthly during recruitment and quarterly during follow-up).

DISCUSSION

This study will provide evidence of the effectiveness and cost-effectiveness of HD as compared to HDF for adults with kidney failure in-centre HD or HDF. It will inform management for this patient group in the UK and internationally.

TRIAL REGISTRATION

ISRCTN10997319 . Registered on 10 October 2017.

Personalizing treatment in end-stage kidney disease: deciding between hemodiafiltration and hemodialysis based on individualized treatment effect prediction

Background

Previous studies suggest that hemodiafiltration reduces mortality compared to hemodialysis in patients with end-stage kidney disease (ESKD), but controversy surrounding its benefits remain and it is unclear to what extent individual patients benefit from hemodiafiltration. This study aimed to develop and validate a treatment effect prediction model to determine which patients would benefit most from hemodiafiltration compared to hemodialysis in terms of all-cause mortality.

Methods

Individual participant data from four randomized controlled trials comparing hemodiafiltration with hemodialysis on mortality were used to derive a Royston-Parmar model for prediction of absolute treatment effect of hemodiafiltration based on pre-specified patient and disease characteristics. Validation of the model was performed using internal-external cross validation.

Results

The median predicted survival benefit was 44 (Q1-Q3: 44–46) days for every year of treatment with hemodiafiltration compared to hemodialysis. The median survival benefit with hemodiafiltration ranged from 2 to 48 months. Patients who benefited most from hemodiafiltration were younger, less likely to have diabetes or a cardiovascular history and had higher serum creatinine and albumin levels. Internal-external cross validation showed adequate discrimination and calibration.

Conclusion

Although overall mortality is reduced by hemodiafiltration compared to hemodialysis in ESKD patients, the absolute survival benefit can vary greatly between individuals. Our results indicate that the effects of hemodiafiltration on survival can be predicted using a combination of readily available patient and disease characteristics, which could guide shared decision-making.

Clinical performance, intermediate and long-term outcomes of high-volume hemodiafiltration in patients with kidney failure

Hemodiafiltration (HDF), in which both convective and diffusion methods are combined, yields an increased overall solute clearance compared with hemodialysis (HD), specifically for medium and larger molecular weight uremic toxins. Due to uncertainty in the treatment effects, the nephrology community still perceives the implementation of HDF and the achievement of high convective volume as complex. In this article, we review practical aspects of the implementation of HDF that can effectively deliver a high-volume HDF therapy and assure clinical performance to most patients. We also present an overview of the impact of high-volume HDF (compared to HD) on a series of relevant biochemical, patient-reported, and clinical outcomes, including uremic toxin removal, phosphate, Inflammation and oxidative stress, hemodynamic stability, cardiac outcomes, nutritional effects, health-related quality of life, morbidity, and mortality.

Light Chain Cast Nephropathy in Multiple Myeloma: Prevalence, Impact and Management Challenges

“Cast nephropathy” (CN) is a pathological feature of myeloma kidney, also seen to a lesser extent in the context of severe nephrotic syndrome from non-haematological diseases. The name relates to obstruction of distal tubules by “casts” of luminal proteins concentrated by intensive water reabsorption resulting from dehydration or high-dose diuretics. Filtered proteins form complexes with endogenous tubular Tamm-Horsfall glycoprotein. The resulting gel further slows or stops luminal flow upon complete obstruction of distal convoluted tubules and collecting ducts. Thus, a tubular obstructive form of acute kidney injury (AKI) is a common consequence of CN. The pathogenesis of CN will be reviewed in light of recent advances in the understanding of monoclonal disorders of B lymphocytes, leading to the release of immunoglobulin components (free light chains, FLC) into the bloodstream and their filtration across the glomerular basement membrane. Treatment aiming at reduction of the circulating burden of FLC may help recovery of renal function in a fraction of these patients, besides filling the void between the onset of AKI, histopathological diagnosis, and full response to pharmacologic treatment.

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High volume online post-dilution hemodiafiltration: how relevant is it in chronic kidney disease?

Online hemodiafiltration is potentially a superior mode of dialysis compared to conventional hemodialysis. However, prospective randomized controlled trials have failed to demonstrate such superiority. Post-hoc analyses of these trials have indicated that high volume post-dilution hemodiafiltration is associated with lower death rates than conventional dialysis. This study discusses whether the lower death rates ascribed to high volume hemodiafiltration are linked to convection volume or the time on dialysis needed to achieve high convection volumes.

Hemodiafiltration in developing countries

Hemodiafiltration (HDF) is a promising kidney replacement therapy modality for patients with end-stage kidney disease. The principle of uremic toxin clearance by combining convection and diffusion can lead to greater benefits compared to conventional hemodialysis. Evidence is building that supports the advantages of HDF with short-term outcomes such as greater intradialytic hemodynamic stability, improved nutritional status, attenuation of anemia, and reduction of inflammatory cytokines which produce improved key long-term impacts including survival and cardiovascular outcomes. Very little is known about the prevalence of HDF treatments in developing countries due to a shortage of national kidney registries. HDF experience is limited in many countries due to the cost of dialysis treatments, availability of online HDF machines, and reimbursement policies. These obstacles have led to nephrologists developing innovations, for example, convective control HDF (CC-HDF), simple mid-dilution, and simple mixed-dilution methods, which may be as effective as commercially available HDF machines. In this article, we will focus on the experience of HDF practice and barriers to adoption in developing countries. Results can guide clinical practice recommendations for implementing HDF in resource-limited settings.