Leptin and β2-Microglobulin Kinetics with Three Different Dialysis Modalities

Is hemodiafiltration superior to high-flow hemodialysis in reducing all-cause and cardiovascular mortality in kidney failure patients? A meta-analysis of randomized controlled trials

INTRODUCTION

Hemodiafiltration (HDF) and high-flux hemodialysis (hf-HD) are different methods of kidney replacement therapy (KRT) used for the treatment of kidney failure patients. A debate has raged over the last decade about the survival benefit of patients with the use of HDF compared with hf-HD, but with divergent results from randomized controlled trials. Therefore, this study aimed to perform a meta-analysis to compare HDF and hf-HD regarding all-cause and cardiovascular mortality.

METHODS

PubMed and Cochrane databases were searched until July 19, 2023, for randomized clinical trials comparing HDF and hf-HD in patients on maintenance dialysis. A meta-analysis was performed using Stata 16.1, applying fixed or random effect models according to the heterogeneity between studies.

FINDINGS

Of the 496 studies found, five met the inclusion criteria. Compared with the hf-HD group, the risk ratio (RR) for all-cause mortality with HDF use was 0.76 (95% CI: 0.67-0.88, I2 = 0%). HDF was associated with lower cardiovascular mortality, although the sensitivity analysis showed that the result differed between scenarios. Subgroup analysis showed lower all-cause mortality among patients without diabetes in the HDF group compared with hf-HD (RR 0.66, 95% CI: 0.51-0.81, I2 = 0%), but not in diabetic patients (RR = 0.89, 95% CI: 0.65-1.12, I2 = 0.0%). A subgroup analysis considering convection volumes was not performed, but the studies with the highest weight in the meta-analysis described convection volume as more than 20 L/session.

DISCUSSION

More clinical studies considering critical risk factors, such as advanced age and preexisting cardiovascular disease, are needed to confirm the supremacy of HDF over hf-HD on the survival of patients treated by these two forms of kidney replacement therapy.

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.

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.

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.

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.

Comparative efficacy between hemodialysis using super high-flux dialyzer with hemoperfusion and high-volume postdilution online hemodiafiltration in removing protein bound and middle molecule uremic toxins: A cross-over randomized controlled trial

BACKGROUND

Hemodialysis (HD) using super high-flux dialyzer (HD + SHF) comparably removed uremic toxins to high-volume postdilution online hemodiafiltration (olHDF). Integration of hemoperfusion (HP) to HD + SHF (HD + SHF + HP) might provide superior uremic toxin removing capability to high-volume postdilution olHDF.

METHOD

The present study was conducted in thrice-a-week HD patients to compare the efficacy in removing indoxyl sulfate (IS), beta-2 microglobulin (β₂ M), and urea between high-volume postdilution ol-HDF and HD + SHF + HP, comprising HD + SHF as the main treatment plus HD + SHF + HP 1/week in the first 4 weeks and 1/2 weeks in the second 4 weeks.

RESULTS

Ten prevalent HD patients with blood flow rate (BFR) above 400 ml/min were randomized into two sequences of 8-week treatment periods of HD + SHF + HP and later high-volume postdilution olHDF or vice versa. When compared with high-volume postdilution olHDF (convective volume of 26.02 ± 1.8 L/session), HD + SHF + HP provided comparable values of percentage reduction ratio of IS (52.0 ± 11.7 vs. 56.3 ± 7.5%, p = 0.14) and β₂ M (83.7 ± 4.9 vs. 84.0 ± 4.3%, p = 0.37) and slightly lower urea reduction ratio. Despite greater dialysate albumin loss (p = 0.008), there was no significant change in serum albumin level in HD + SHF + HP group.

CONCLUSIONS

HD + SHF + HP could not provide superior efficacy in removing uremic toxins to high-volume postdilution olHDF. The use of low BFR of 200 ml/min during the first 2 h of HD + SHF + HP session, according to the instruction of manufacturer, might impair the efficacy of the HD + SHF part in removing uremic toxins.

Reduction of protein-bound uraemic toxins in plasma of chronic renal failure patients: A systematic review

BACKGROUND

Protein-bound uraemic toxins (PBUTs) accumulate in patients with chronic kidney disease and impose detrimental effects on the vascular system. However, a unanimous consensus on the most optimum approach for the reduction of plasma PBUTs is still lacking.

METHODS

In this systematic review, we aimed to identify the most efficient clinically available plasma PBUT reduction method reported in the literature between 1980 and 2020. The literature was screened for clinical studies describing approaches to reduce the plasma concentration of known uraemic toxins. There were no limits on the number of patients studied or on the duration or design of the studies.

RESULTS

Out of 1274 identified publications, 101 studies describing therapeutic options aiming at the reduction of PBUTs in CKD patients were included in this review. We stratified the studies by the PBUTs and the duration of the analysis into acute (data from a single procedure) and longitudinal (several treatment interventions) trials. Reduction ratio (RR) was used as the measure of plasma PBUTs lowering efficiency. For indoxyl sulphate and p-cresyl sulphate, the highest RR in the acute studies was demonstrated for fractionated plasma separation, adsorption and dialysis system. In the longitudinal trials, supplementation of haemodialysis patients with AST-120 (Kremezin®) adsorbent showed the highest RR. However, no superior method for the reduction of all types of PBUTs was identified based on the published studies.

CONCLUSIONS

Our study shows that there is presently no technique universally suitable for optimum reduction of all PBUTs. There is a clear need for further research in this field.

The efficiency of continuous renal replacement therapy for rewarming of patients in accidental hypothermia--An experimental study

Severe accidental hypothermia carries high mortality and morbidity and is often treated with invasive extracorporeal methods. Continuous veno-venous hemodiafiltration (CVVHDF) is widely available in intensive care units. We sought to provide theoretical basis for CVVHDF use in rewarming of hypothermic patients. CVVHDF system was used in the laboratory setting. Heat balance and transferred heat units were evaluated for the system without using blood. We used 5L of crystalloid solution at the temperature of approximately 25°C, placed in a thermally insulated tank (representing the "central compartment" of a hypothermic patient). Time of warming the central compartment from 24.9 to 30.0°C was assessed with different flow combinations: "blood" (central compartment fluid) 50 or 100 or 150 mL/min, dialysate solution 100 or 1500 mL/h, and substitution fluid 0 or 500 mL/h. The total circulation time was 1535 minutes. There were no differences between heat gain values on the filter depending on blood flow (P = .53) or dialysate flow (P = .2). The mean heating time for "blood" flow rates 50, 100, and 150 mL/min was 113.7 minutes (95% CI, 104.9-122.6 minutes), 83.3 minutes (95% CI, 76.2-90.3 minutes), and 74.7 minutes (95% CI, 62.6-86.9 minutes), respectively (P < .01). The respective median rewarming rate for different "blood" flows was 3.6°C/h (IQR, 3.0-4.2°C/h), 4.8 (IQR, 4.2-5.4°C/h), and 5.4 (IQR, 4.8-6.0°C/h), respectively (P < .01). The dialysate flow did not affect the warming rate. Based on our experimental model, CVVHDF may be used for extracorporeal rewarming, with the rewarming rates increasing achieved with higher blood flow rates.

Elimination of Uremic Toxins by Functionalized Graphene-Based Composite Beads for Direct Hemoperfusion

Conventional absorbents for hemoperfusions suffer from low efficiency and slow absorption with numerous side effects. In this research, we developed cellulose acetate (CA) functionalized graphene oxide (GO) beads (∼1.5-2 mm) that can be used for direct hemoperfusion, aiming at the treatment of kidney dysfunction. The CA-functionalized GO bead facilitates adsorption of toxins with high biocompatibility and high-efficiency of hemoperfusion while maintaining high retention for red blood cell, white blood cells, and platelets. Our in vitro results show that the toxin concentration for creatinine reduced from 0.21 to 0.12 μM (p < 0.005), uric acid from 0.31 to 0.15 mM (p < 0.005), and bilirubin from 0.36 to 0.09 mM (p < 0.005), restoring to normal levels within 2 h. Our in vivo study on rats (Sprague-Dawley, n = 30) showed that the concentration for creatinine reduced from 83.23 to 54.87 μmol L^-1 (p < 0.0001) and uric acid from 93.4 to 54.14 μmol L^-1 (p < 0.0001), restoring to normal levels within 30 min. Results from molecular dynamics (MD) simulations using free-energy calculations reveal that the presence of CA on GO increases the surface area for adsorption and enhances penetration of toxins in the binding cavities because of the increased electrostatic and van der Waals force (vdW) interactions. These results provide critical insight to fabricate graphene-based beads for hemoperfusion and to have the potential for the treatment of blood-related disease.

Hemodiafiltration to Address Unmet Medical Needs ESKD Patients

Hemodiafiltration combines diffusive and convective solute removal in a single therapy by ultrafiltering 20% or more of the blood volume processed using a high-flux hemodialyzer and maintaining fluid balance by infusing sterile nonpyrogenic replacement fluid directly into the patient's blood. In online hemodiafiltration, the large volumes of replacement fluid required are obtained by online filtration of standard dialysate through a series of bacteria- and endotoxin-retaining filters. Currently available systems for online hemodiafiltration are on the basis of conventional dialysis machines with added features to safely prepare and infuse replacement fluid and closely control fluid balance. Hemodiafiltration provides greater removal of higher molecular weight uremic retention solutes than conventional high-flux hemodialysis, and recently completed randomized, controlled clinical trials suggest better patient survival with online hemodiafiltration compared with standard high-flux hemodialysis when a high convection volume is delivered. Hemodiafiltration is also associated with improvements in other clinical outcomes, such as a reduction in intradialytic hypotension, and it is now used routinely to treat >100,000 patients, mainly in Europe and Japan.

Randomised, open-label, multicentre trial comparing haemodialysis plus haemoperfusion versus haemodialysis alone in adult patients with end-stage renal disease (HD/HP vs HD): study protocol

INTRODUCTION

Haemodialysis (HD) is the cornerstone treatment for patients with end-stage renal disease (ESRD). However, highly protein bound or large molecular weight uremic toxins such as phenolic and indolic compounds and homocysteine, which are associated with adverse outcomes such as cardiovascular disease of patients with ESRD, are difficult to remove via HD but can be effectively eliminates by haemoperfusion (HP). The proposed trial (referred to as HD/HP vs HD below) is a randomised, open-label, multicentre trial comparing HD plus HP versus HD alone in adult patients with ESRD. The primary endpoint measure is all-cause mortality.

METHODS AND ANALYSIS

We plan to enrol 1364 maintenance HD patients from 11 medical centres in Shanghai. Participants will be randomised to receive HD plus HP or HD alone at a 1:1 ratio after 1-month run-in period. In both arms, patients will receive low-flux HD at a frequency of two times a week and haemodiafiltration at a frequency of once a week. In the intervention group, subjects also received HP once every 2 weeks. Follow-up is scheduled at 3, 6, 12, 18 and 24 months after randomisation, and will consist the following: routine physical examinations, standard lab panels (blood routine, liver/residual kidney functions, tests of the coagulation system, etc), dialysis adequacy (standard Kt/V), chest X-ray, ECG, echocardiography, heart function rating. Adverse events will be assessed according to the international conference on harmonisation guidelines. The primary outcome is 24-month all-cause mortality. Secondary outcomes will include cardiovascular-related mortality, the occurrence of major cardiovascular events and the quality of life.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ethical Committees of all 11 participating centres. Clinical Research Unit of Xin Hua Hospital will oversee the study. The results will be presented at national and international academic meetings, and submitted to peer-reviewed journals for publications.

TRIAL REGISTRATION NUMBER

NCT03227770; Pre-results.

[Online hemodiafiltration: Practical aspects, safety and efficacy]

Purification of high molecular uremic toxins by conventional hemodialysis is limited. It remains associated with a high morbidity and excessively high mortality. Online hemodiafiltration using a high permeability hemodiafilter, an ultrapure dialysate, and which tends to maximize substitution volumes, provides a high efficiency and low bio-incompatibility renal supplementation. Regular use of online hemodiafiltration is associated with reduced morbidity (reduction of intradialytic hypotension episodes, improved blood pressure control, reduced inflammatory profile, better anemia correction and prevention of β₂-microglobulin-associated amyloidosis). Recently, several cohort studies have shown that hemodiafiltration with high substitution volume was associated with a significant reduction in mortality. Randomized studies have been conducted in Europe to confirm these facts. The high safety of online hemodiafiltration has been confirmed in clinical practice by prospective studies. Online hemodiafiltration has reached its full maturity phase and is expected to represent the new standard of renal replacement therapy.

Curative effect of neutral macroporous resin hemoperfusion on treating hemodialysis patients with refractory uremic pruritus

This study aims to investigate the efficacy and safety of neutral macroporous resin hemoperfusion in treating maintenance hemodialysis (MHD) patients with refractory uremic pruritus (RUP).Ninety patients were enrolled and were randomly divided into 3 groups: control group, experiment 1 group, and experiment 2 group. Clinical symptom scores of skin itching were recorded before and at 4 and 8 weeks after the treatment. In addition, serum parathyroid hormone (PTH), calcium (Ca), phosphorus (P), and C-reactive protein (CRP) were detected; and the calcium-phosphorus product ([Ca] × [P]) was calculated to compare the curative effect.VSA score, modified Duo pruritus score, and CRP: these indices decreased to some extent at 4 and 8 weeks after treatment in the 2 experiment groups, compared with pretreatment (P < 0.05); and differences among these 3 groups were statistically significant (P < 0.05). PTH, P, and [Ca] × [P]: these indices decreased to some extent at 4 and 8 weeks after treatment in the 2 experiment groups, compared with pretreatment (P < 0.05); and differences between the control and experiment 1 groups, as well as between the control and experiment 2 groups, were statistically significant (P < 0.05). However, the difference between the experiment 1 and experiment 2 groups were not statistically significant (P < 0.05).The effects of HA330 and HA130 resin hemoperfusion apparatus on secondary hyperparathyroidism and the disorder of calcium and phosphorus metabolism are similar. The mechanism may be related to its strong adsorption effect, and its capacity to widely remove inflammatory mediators, immune mediators, and endotoxins.

Dialyzer Reuse and Outcomes of High Flux Dialysis

Background

The bulk of randomized trial evidence for the expanding use of High Flux (HF) hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO) allowed, while the other (Membrane Outcomes Permeability, MPO) excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF) dialyzers.

Methods

Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M) concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO.

Findings

In HEMO, minimally reused (< 6 times) HF dialyzers were associated with a hazard ratio (HR) of 0.67 (95% confidence interval, 95%CI: 0.48–0.92, p = 0.015), 0.64 (95%CI: 0.44 – 0.95, p = 0.03), 0.61 (95%CI: 0.41 – 0.90, p = 0.012), 0.53 (95%CI: 0.28 – 1.02, p = 0.057) relative to minimally reused LF ones for all cause, cardiovascular, cardiac and infectious mortality respectively. These relationships reversed for extensively reused membranes (p for interaction between reuse and flux < 0.001, p = 0.005) for death from all cause and cardiovascular causes, while similar trends were noted for cardiac and infectious mortality (p of interaction between reuse and flux of 0.10 and 0.08 respectively). Reduction of β2M explained only 1/3 of the effect of minimally reused HF dialyzers on all cause mortality, while non-β2M related factors explained the apparent attenuation of the benefit with more extensively reused dialyzers. Meta-regression of HEMO and MPO estimated an adjusted HR of 0.63 (95% CI: 0.51–0.78) for non-reused HF dialyzers compared with non-reused LF membranes.

Conclusions

This secondary analysis and synthesis of two large hemodialysis trials supports the widespread use of HF dialyzers in clinical hemodialysis over the last decade. A mechanistic understanding of the effects of HF dialysis and the reuse process on dialyzers may suggest novel biomarkers for uremic toxicity and may accelerate membrane technology innovations that will improve patient outcomes.

Leptin as an uremic toxin: Deleterious role of leptin in chronic kidney disease

White adipose tissue secretes a large variety of compounds named adipokines amongst which, leptin exhibits pleiotropic metabolic actions. Leptin is an anorexigenic hormone, secreted in proportion of fat mass, with additional effects on the regulation of inflammation, cardiovascular system, immunity, hematopoiesis and bone metabolism. Chronic kidney disease (CKD) is characterized by an increase of plasma leptin concentration that may be explained by a lack of renal clearance. Hyperleptinemia plays a key role in the pathogenesis of complications associated with CKD such as cachexia, protein energy wasting, chronic inflammation, insulin resistance, cardiovascular damages and bone complications. Leptin is also involved in the progression of renal disease through its pro-fibrotic and pro-hypertensive actions. Most of the adverse effects of leptin have been documented both experimentally and clinically. Leptin may therefore be considered as an uremic toxin in CKD. The aim of this review is to summarize the pathophysiological and clinical role of leptin in in vitro studies, experimental models, as well as in patients suffering from CKD.

Convective therapies versus low-flux hemodialysis for chronic kidney failure: a meta-analysis of randomized controlled trials

BACKGROUND

Although convective therapies have gained popularity for the optimal removal of uremic solutes, their benefits and potential risks have not been fully elucidated. We conducted a meta-analysis of all randomized controlled trials comparing convective therapies with low-flux hemodialysis in patients with chronic kidney failure.

METHODS

We performed a literature search using MEDLINE (inception-December 2012), Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, scientific abstracts from meetings and bibliographies of retrieved articles. Randomized controlled trials comparing the effect of convective therapies including high-flux hemodialysis, hemofiltration or hemodiafiltration versus low-flux hemodialysis were included. Random-effects model meta-analyses were used to examine continuous and binary outcomes.

RESULTS

Sixty-five (29 crossover and 36 parallel-arm) trials were identified (n = 12 182). Convective therapies resulted in a decrease in all-cause mortality [relative risk (RR) 0.88; 95% confidence interval (CI) 0.76, 1.02, P = 0.09], cardiovascular mortality (RR 0.84; 95% CI 0.71, 0.98, P = 0.03), all-cause hospitalization (RR 0.91; 95% CI 0.82, 1.01; P = 0.08) and therapy-related hypotension (RR 0.55, 95% CI 0.35, 0.87, P = 0.01). Convective therapies also resulted in an increase in the clearance of several low-molecular-weight (urea, creatinine and phosphate), middle-sized (β-2 microglobulin and leptin) and protein-bound (homocysteine, advanced glycation end-products and pentosidine) solutes and a decrease in inflammatory markers (interleukin-6). There was no impact of convective therapies on cardiac morphological and functional parameters, and blood pressure and anemia parameters.

CONCLUSIONS

Although convective therapies are associated with improved clearance of uremic solutes, the potential long-term benefits of specific convective modalities require further study.

Survival of incident patients on high-volume online hemodiafiltration compared to low-volume online hemodiafiltration and high-flux hemodialysis

BACKGROUND

Hemodiafiltration is becoming a preferred treatment modality for dialysis patients in many countries. The volume of substitution fluid delivered has been indicated as an independent mortality risk factor. The aim of this study is to compare patient survival on three different treatment modalities: high-flux hemodialysis, low-volume online HDF (oHDF) and high-volume oHDF.

METHODS

Incident hemodialysis and oHDF patients treated in 13 NephroCare centers in Bosnia and Herzegovina, Serbia and Slovenia between January 1, 2007, and December 31, 2011, were included in this epidemiological cohort study. High-volume oHDF was defined as substitution volume higher than the median substitution volume infused, otherwise low-volume. Main predictor was treatment modality at baseline and in time-dependent model. Other predictors were age, gender, diabetes mellitus, cerebrovascular accident, arrhythmia, hemoglobin and C-reactive protein.

RESULTS

Four hundred and forty-two patients were included in the study. Median substitution fluid volume was 20.4 L. Mean difference between the oHDF groups in substitution fluid volume was 8.3 ± 5.2 L [95 % confidence intervals (95 % CI) 7.1-9.5, p < 0.0001]. The unadjusted hazard ratios (HR) with 95 % CI compared to high-flux HD were 0.87 (0.5-1.5) for low-volume oHDF and 0.29 (0.13-0.63) for high-volume oHDF. After the adjustment for covariates, the HR for patients on low-volume oHDF remained statistically insignificant compared to high-flux HD (0.84; 95 % CI 0.46-1.53), while patients on high-volume oHDF showed a marked and significantly lower HR (0.29; 95 % CI 0.13-0.68) than patients on high-flux HD in baseline model. While this effect failed to reach significance in the time-dependent model (HR 0.477; 95 % CI 0.196-1.161), possibly due to an inadequate sample size here, the consistency of results in both models supports the robustness of the findings. After switching from high-flux hemodialysis to oHDF, mean hemoglobin and albumin levels did not change significantly. Mean erythropoietin resistance index (ERI) and erythropoiesis stimulating agents (ESA) consumption decreased significantly (p = 0.02, p = 0.03, respectively).

CONCLUSIONS

The median substitution volume used in these three countries for post-dilutional oHDF is 20.4 L. oHDF is associated with significant reductions in ERI and ESA consumption. Only high-volume oHDF is associated with improved survival compared to high-flux hemodialysis.

Combination of maintenance hemodialysis with hemoperfusion: a safe and effective model of artificial kidney

OBJECTIVE

To investigate whether the combination of maintenance hemodialysis (MHD) with hemoperfusion (HP) could improve the clearance rate of middle and large molecule uremic toxins so as to improve the quality of life of MHD patients and reduce their mortality rate.

METHODS

This study was a prospective, randomized, controlled clinical trial. 100 MHD patients were selected and then randomly divided into two groups after four weeks of run-in period. Group 1 received HD alone 2 times a week and the combined treatment of HD with HP (HD+HP) once a week, whereas Group 2 was given HD alone 3 times a week. This study was followed up for a mean of 2 years. The primary outcome was the death of patients. Secondary end points included normal clinical data, leptin, high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), ß(2) microglobulin (ß(2)-MG), immunoreactive parathyroid hormone (iPTH), tumor necrosis factor-α (TNF-α) and the index of dimensions of Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36 Chinese Edition ).

RESULTS

At the end of the two-year observation, the serum concentration of leptin, hsCRP, iPTH, IL-6, ß(2)-MG and TNF-α, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), cardiothoracic ratio, left ventricular mass index (LVMI), the EPO doses and the types of antihypertensive drugs used were lower with Group 1 than with Group 2 (p<0.05); Group 1 had higher hemoglobin (Hb), ejection fraction (EF), and body mass index (BMI) (p<0.05). No statistical difference between the two groups was observed in terms of serum albumin, serum iron (SI), total iron binding capacity (TIBC), cardiac output (CO), Kt/V, early/atrial mitral inflow velocities (E/A) (p>0.05). Besides, the SF-36 indicated that the total score of overall dimentions of Group 1 was higher than Group 2 (p<0.05) and the quality of life of Group 1 was evidently better than Group 2. The Kaplan-Meier Survival Curves for the 2-year observation period showed that patients in Group 1 had obvious survival advantage while Log-rank test results showed p<0.05. No serious adverse incidents occurred during the HD+HP treatment.

CONCLUSIONS

HD+HP was superior to HD in regularly eliminating middle and large molecule uremic toxins accumulated in the body. These findings suggest a potential role for HD+HP in the treatment to improve the quality of life and survival rate of MHD patients.

Effect of different dialysis modalities on microinflammatory status and endothelial damage

BACKGROUND AND OBJECTIVES

We studied the relationship between microinflammation and endothelial damage in chronic kidney disease (CKD) patients on different dialysis modalities.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Four groups of CKD stage 5 patients were studied: 1) 14 nondialysis CKD patients (CKD-NonD); 2) 15 hemodialysis patients (HD); 3) 12 peritoneal dialysis patients with residual renal function >1 ml/min (PD-RRF >1); and 4) 13 peritoneal dialysis patients with residual renal function <or=1 ml/min (PD-RRF <or=1). Ten healthy subjects served as controls. CD14(+)CD16(+) cells and apoptotic endothelial microparticles (EMPs) were measured by flow cytometry. Serum vascular endothelial growth factor (VEGF) was measured by ELISA.

RESULTS

CKD-NonD and HD patients had a higher percentage of CD14(+)CD16(+) monocytes than PD groups and controls. CD14(+)CD16(+) was similar in the PD groups, regardless of their RRF, and controls. The four uremic groups displayed a marked increase in apoptotic EMPs and VEGF compared with controls. Apoptotic EMPs and VEGF were significantly higher in HD patients than in CKD-NonD and both PD groups. However, there were no significant differences between CKD-NonD and the two PD groups. There was a correlation between CD14(+)CD16(+) and endothelial damage in CKD-NonD and HD patients, but not in PD and controls.

CONCLUSIONS

There was an increase in CD14(+)CD16(+) only in CKD-NonD and HD patients. In these patients, there was a relationship between increased CD14(+)CD16(+) and endothelial damage. These results strongly suggest that other factors unrelated to the microinflammatory status mediated by CD14(+)CD16(+) are promoting the endothelial damage in PD, regardless of their RRF.