A Randomized, Single-Blind, Crossover Trial of Recovery Time in High-Flux Hemodialysis and Hemodiafiltration

Delayed post-dialysis recovery times are associated with relative changes in intracellular and extracellular fluid ratios between different body compartments

INTRODUCTION

Hemodialysis patient groups have advocated reducing dialysis fatigue and symptoms. We investigated whether compartmental fluid shifts were associated with peri-dialytic fatigue and symptoms.

METHODS

Sessional dialysis records of patients reporting both a short and delayed recovery (<1 h and ≥1 h) with corresponding bioimpedance measurements were reviewed.

RESULTS

One hundred and twenty-four patients reported both short and delayed recovery times, mean age 66.0 ± 14.8 years, 66.1% male. Differences between sessions included higher distress thermometer [4 (1-6) vs. 3 (0-5)], fatigue [4 (0-9) vs. 2 (0-7)], total symptom scores [20.5 (12.3-34.5) vs. 16 (7-28)], change in extracellular water to total body water ratios between body compartments [right leg/left arm 2.36 (1.23-4.19) vs. 1.28 (0.12-2.01), all p < 0.01] with delayed recovery, and more hemodialysis than hemodiafiltration sessions (χ2 4.6, p = 0.02).

CONCLUSION

Sessions with prolonged recovery times were associated with more peri-dialytic symptoms, psychological distress, and hemodialysis mode, and greater changes in compartmental fluid shifts.

Intradialytic Tolerance and Recovery Time in Different High-Efficiency Hemodialysis Modalities

There are several forms of maintenance high-efficiency hemodialysis (HD), including hemodiafiltrations (HDF) in different technical modes and expanded HD, using dialyzers with medium cut-off membranes. The aim of the study was to assess the intradialytic tolerance and length of dialysis recovery time (DRT) in these modalities. This is an exploratory, crossover study in maintenance HD patients with low comorbidity and no clinical indications for the use of high-efficiency HD, who were exposed to five intermittent dialyses in random order: high-flux hemodialysis (S-HD), expanded HD (HDx), pre-dilution HDF (PRE-HDF), mix-dilution HDF (MIX-HDF) and post-dilution HDF (POST-HDF). Twenty-four dialysis sessions of each method were included in the analysis. Dialysis parameters, including blood flow rate, dialysis fluid flow rate and temperature, and pharmacological treatment were constant. Average total convection volume for post-HDF, pre-HDF and mix-HDF were 25.6 (3.8), 61.5 (7.2) and 47.1 (11.4) L, respectively. During all therapies, patients were monitored for the similarity of their hydration statuses using bioimpedance spectroscopy, and for similar variability over time in systemic blood pressure and cardiac output, while peripheral resistance was monitored using impedance cardiography. The lowest frequency of all intradialytic adverse events were observed during HDx. Delayed DRT was the shortest during PRE-HDF. Patients were also more likely to report immediate recovery while receiving PRE-HDF. These differences did not reach statistical significance; however, the study results suggest that intradialytic tolerance and DRT may depend on the dialysis method used. This supports the need of taking into account patient preferences and quality of life while individualizing high-efficiency therapy in HD patients.

Fatigue in Patients Receiving Maintenance Hemodialysis: A Review

Fatigue surrounding hemodialysis treatments is a common and often debilitating symptom that impacts patients' quality of life. Intradialytic fatigue develops or worsens immediately before hemodialysis and persists through the dialysis treatment. Little is known about associated risk factors or pathophysiology, although it may relate to a classic conditioning response. Postdialysis fatigue (PDF) develops or worsens after hemodialysis and may persist for hours. There is no consensus on how to measure PDF. Estimates for the prevalence of PDF range from 20%-86%, likely due to variation in methods of ascertainment and participant characteristics. Several hypotheses seek to explain the pathophysiology of PDF, including inflammation, hypothalamic-pituitary-adrenal axis dysregulation, and osmotic and fluid shifts, but none is currently supported by compelling or consistent data. PDF is associated with several clinical factors, including cardiovascular and hemodynamic effects of the dialysis procedure, laboratory abnormalities, depression, and physical inactivity. Clinical trials have reported hypothesis-generating data about the utility of cold dialysate, frequent dialysis, clearance of large middle molecules, treatment of depression, and exercise as potential treatments. Existing studies are often limited by sample size, lack of a control group, observational design, or short intervention duration. Robust studies are needed to establish the pathophysiology and management of this important symptom.

Systematic review to compare the outcomes associated with the modalities of expanded hemodialysis (HDx) versus high-flux hemodialysis and/or hemodiafiltration (HDF) in patients with end-stage kidney disease (ESKD)

BACKGROUND

This systematic review was performed to identify recent published comparative evidence on the efficacy, effectiveness, and safety of expanded hemodialysis (HDx) versus high-flux HD and/or hemodiafiltration (HDF) for long-term outcomes in end-stage kidney disease.

METHODS

Systematic literature review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Medline, Medline® Epub Ahead of Print, EconLit, Embase, and EBM reviews were searched to identify relevant publications from 2013 onwards. Eligibility criteria included clinical studies reporting mortality, hospitalizations, cardiovascular outcomes, economic evaluations, cost studies, and quality of life (QoL) studies.

RESULTS

A total of 79 relevant studies were identified with 29 prioritized for detailed analysis; four compared HDx to HD, one compared HDF and HDx, and 24 compared HDF with HD. A total of 13 randomized controlled trial (RCT)-based studies were identified; 11 compared HDF with HD, one compared HDx with HD, and one compared HDF with HDx. Follow-up duration ranged from 16 weeks to 7 years for HDF studies and from 12 weeks to 1 year for HDx studies. HDF showed significant improvements in mortality, cardiovascular outcomes, hospitalizations, and QoL versus high-flux HD. One study reported mortality outcomes for HDx and found no difference versus HDF. QoL benefits with HDx were reported in a small number of studies.

CONCLUSION

The efficacy and safety of HDF is supported by a robust evidence base that includes several RCTs. While HDx may offer benefits over high-flux HD, long-term studies are required to compare HDx with online high volume HDF.

REGISTRATION

PROSPERO registration number: CRD42022301009.

Post-dialysis fatigue: Comparison of bicarbonate hemodialysis and online hemodiafiltration

INTRODUCTION

The present cross-sectional study aimed to compare the prevalence, the characteristics of post-dialysis fatigue and the length of recovery time after hemodialysis in prevalent end-stage renal disease patients (ESRD) receiving bicarbonate hemodialysis (HD) or hemodiafiltration (HDF).

METHODS

Patients were suffering from post-dialysis fatigue if they spontaneously offered this complaint when asked the open-ended question: "Do you feel fatigued after dialysis?". Moreover, each patient was invited to rate the intensity, duration, and frequency of post-dialysis fatigue from 1 to 5. In order to assess RECOVERY TIME AFTER DIALYSIS, patients were invited to answer to the following single open-ended question: "How long does it take you to recover from a dialysis session?"

FINDINGS

We included 335 patients: 252 received HD and 83 received HDF. Post-dialysis fatigue was present in 204 patients (60.9%). Prevalence of post-dialysis fatigue did not differ significantly between patients on HD (62.3%) and on HDF (56.6%; p = 0.430). Median recovery time after dialysis was 180 min [180-240] and did not differ significantly between the two subgroups (180 min [130-240] and 240 min [120-332] p = 0.671, respectively). Median post-dialysis fatigue intensity, duration, and frequency were 3 [1-5], 3 [1-5], and 4 [1-5] and did not differ significantly between patients on HD and on HDF. At the multivariate analysis, age, ADL and hemoglobin levels were the independent predictors of the HDF treatment.

DISCUSSION

Prevalence and characteristics of post-dialysis fatigue do not differ significantly between patients receiving bicarbonate HD or HDF.

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.

Measuring quality of life in trials including patients on haemodialysis: methodological issues surrounding the use of the Kidney Disease Quality of Life Questionnaire

BACKGROUND

Haemodialysis (HD) treatment causes a significant decrease in quality of life (QoL). When enrolled in a clinical trial, some patients are lost prior to follow-up because they die or they receive a kidney transplant. It is unclear how these patients are dealt with in the analysis of QoL data. There are questions surrounding the consistency of how QoL measures are used, reported and analysed.

METHODS

A systematic search of electronic databases for trials measuring QoL in HD patients using any variation of the Kidney Disease Quality of Life (KDQoL) Questionnaire was conducted. The review was conducted in Covidence version 2. Quantitative analysis was conducted in Stata version 16.

RESULTS

We included 61 trials in the review, of which 82% reported dropouts. The methods to account for missing data due to dropouts include imputation (7%) and complete case analysis (72%). Few trials (7%) conducted a sensitivity analysis to assess the impact of missing data on the study results. Single imputation techniques were used, but are only valid under strong assumptions regarding the type and pattern of missingness. There was inconsistency in the reporting of the KDQoL, with many articles (70%) amending the validated questionnaires or reporting only statistically significant results.

CONCLUSIONS

Missing data are not dealt with according to the missing data mechanism, which may lead to biased results. Inconsistency in the use of patient-reported outcome measures raises questions about the validity of these trials. Methodological issues in nephrology trials could be a contributing factor to why there are limited effective interventions to improve QoL in this patient group.

PROSPERO REGISTRATION

CRD42020223869.

Executive summary of the Korean Society of Nephrology 2021 clinical practice guideline for optimal hemodialysis treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists' support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient's condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There are also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

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.

Patient-reported outcomes and patient voices

Online hemodiafilration (HDF) treatment may be associated with better quality of life due to improved clearance of middle-molecular-weight uremic toxins and hemodynamic stability in dialysis patients, in addition to better overall survival.

The rationale and clinical potential of on-line hemodiafiltration as renal replacement therapy

On-line hemodiafiltration (ol-HDF) was developed in the 1980s in response to the unmet medical needs observed with conventional low- and high-flux hemodialysis. Firstly, the limited overall efficacy of conventional HD treatment programs as compared to native kidney function has been consistently documented over the broad MW spectrum of uremic toxins as well as fluid volume and hemodynamic control. Secondly, the unphysiological profile of intermittent treatment leading to repetitive dialysis-induced hemodynamic stress is now a well-recognized component of cardiovascular disease and end organ damage. Thirdly, the bioincompatibility of patient-dialysis system leading to dialysis-induced biological reactions also identified as contributing to dialytic morbidity and mortality. To overcome these limitations and pitfalls, alternative convective-based therapies (hemofiltration and hemodiafiltration), using higher hemoincompatible membranes and ultrapure dialysis fluid, were proposed as a solution to enhance and enlarge MW spectrum of uremic compounds cleared and to reduce dialysis-patient biological interactions. In this context, online HDF appeared soon as the best viable and efficient renal replacement modality to cover these needs. Clinical development and implementation of ol-HDF showed also that dialytic convective dose matters with a threshold point (23 L/1.73 m² in postdilution mode) to observe clinical benefits and outcomes improvements.

Executive Summary of the Korean Society of Nephrology 2021 Clinical Practice Guideline for Optimal Hemodialysis Treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists’ support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient’s condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There is also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

Why and how high volume hemodiafiltration may reduce cardiovascular mortality in stage 5 chronic kidney disease dialysis patients? A comprehensive literature review on mechanisms involved

Online hemodiafiltration (HDF) is an established renal replacement modality for patients with end stage chronic kidney disease that is now gaining rapid clinical acceptance worldwide. Currently, there is a growing body of evidence indicating that treatment with HDF is associated with better outcomes and reduced cardiovascular mortality for dialysis patients. In this comprehensive review, we provide an update on the potential mechanisms which may improve survival in HDF treated patients. The strongest evidence is for better hemodynamic stability and reduced endothelial dysfunction associated with HDF treatments. Clinically, this is marked by a reduced incidence of intradialytic hypotensive episodes, with a better hemodynamic response to ultrafiltration, mediated by an increase in total peripheral vascular resistance and extra-vascular fluid recruitment, most likely driven by the negative thermal balance associated with online HDF therapy. In addition, endothelial function appears to be improved due to a combination of a reduction of the inflammatory and oxidative stress complex syndrome and exposure to circulating cardiovascular uremic toxins. Reports of reversed cardiovascular remodeling effects with HDF may be confounded by volume and blood pressure management, which are strongly linked to center clinical practices. Currently, treatment with HDF appears to improve the survival of dialysis patients predominantly due to a reduction in their cardiovascular burden, and this reduction is linked to the sessional convection volume exchanged.

Quality of Life and Hemodynamic Effects of Switching From Hemodialysis to Hemodiafiltration: A Canadian Controlled Cohort Study

Background:

Recent randomized clinical trials have demonstrated beneficial effects of hemodiafiltration (HDF) compared with hemodialysis (HD) on mortality and hemodynamic stability. Data on quality of life in HDF compared with HD is limited.

Objective:

This study aimed to determine whether patients receiving HD experience improvements in quality of life, hemodynamic and laboratory parameters after switching to HDF.

Design:

Observational controlled cohort study.

Setting & Patients:

Adult patients receiving maintenance dialysis were followed for 3 months both before and after transfer to a new unit, where they received HDF. Prior to transfer, control patients were already treated by HDF.

Methods:

Quality of life at baseline and follow-up was measured using the validated minutes to recovery (MR) question. Dialysis data were collected for 3 consecutive sessions monthly; laboratory values were collected monthly. Wilcoxon signed rank test and repeated measures analysis of covariance were used to evaluate pre/post transfer changes and quantile regression to identify predictors of change in recovery time.

Results:

Of 227 patients, 82 died, were transplanted, were hospitalized or did not transfer, leaving 123 subjects and 22 controls for analysis. MR did not improve with switching to HDF, although patients with MR > 60 min before transfer experienced a significant decrease in their MR, compared with controls. There was no improvement in intradialytic hypotension with HDF. There were no differences in laboratory values before vs after switch.

Limitations:

Nonrandomized single-center study, including only small numbers of patients and covering a short follow-up period; hemodynamic values only evaluated over 1 week per month; residual kidney function not recorded.

Conclusions:

In this Canadian experience of HDF, patients remained stable with respect to several laboratory and dialysis related parameters. Switch to HDF was associated with substantially reduced recovery time in patients with MR > 60 minutes at baseline.

Clinical Assessment of Dialysis Recovery Time and Symptom Burden: Impact of Switching Hemodialysis Therapy Mode

Introduction

Most people on hemodialysis (HD) report a high symptom burden. Fatigue and lack of energy are prominent, interfering with daily life and associated with poor outcome. Prolonged recovery time after each of the thrice weekly dialysis treatments is common. The impact of HD therapies, like expanded hemodialysis (HDx), on patient reported recovery time and symptom burden is unclear.

Methods

A dialysis unit decided to perform regular assessments of patient-reported symptom burden, using the POS-S Renal Symptom questionnaire and the “Recovery time from last dialysis session” question as part of routine patient focused care. At a similar time, a clinical evidence-based decision was taken to switch the in-center dialysis cohort from regular high-flux dialysis membrane to medium cut-off (MCO) membrane, introducing HDx therapy.

Results

Quarterly assessment of patient-reported symptom burden was well accepted. A sustained clinically relevant reduction in post-dialysis recovery time was observed following the therapy switch. In patients providing data up to 12 months (N = 58), median recovery time decreased from 210 min (IQR 7.5–600) to 60 min (0–210; p = 0.002) and 105 min (0–180; p = 0.001) at 6 and 12 months, respectively. Thirty-six percent of individuals reported a recovery time longer than 360 minutes at the initial assessment, which decreased to 9% at 12 months. The POS-S Renal total symptom score showed a decrease at 6 months but no difference from baseline at 12 months. The “fatigue/lack of energy” symptom showed a sustained improvement; the percentage of participants scoring its impact as “severe” or “overwhelming” decreased from 28% at baseline to 16% at 12 months. Changes in other symptoms were more variable.

Conclusion

Regular assessment of patient reported symptoms is feasible in routine dialysis practice and can help in evaluating the impact of clinical interventions. Observations suggest that HDx therapy may reduce post-dialysis recovery time and improve perceived fatigue level.

Development of online hemodiafiltration in Japan

Evidence concerning online hemodiafiltration (ol-HDF) includes increased uremic toxin removal, prevention of dialysis-related hypotension, improved survival, and recovery of dialysis-related uncertain symptoms. In particular, evidence has been shown regarding prevention of dialysis hypotension and improvement of survival, but the mechanism of its manifestation is still unclear and its effects themselves are questionable. In Japan, pre dilution ol-HDF is mainly performed, and improvement in survival rate has been shown on the condition of convection volume is 40 L/session or more. In particular, the removal of α1-microglubulin (αMG), which is a medium-middle solute, is targeted. The antioxidant action (Heme Scavenger) of αMG, is presumed, but in dialysis patients, the majority in serum are deteriorated (oxidized) αMG. It has been pointed out that removing the deteriorated αMG by ol-HDF may produce new αMG from the liver and lead to recovery of the original antioxidant effect. However, clinical evidence of this mechanism is desired. Obtaining evidence for the indicated αMG removal activity of ol-HDF will lead to advancement in HDF.

How biocompatible haemodialysers can conquer the need for systemic anticoagulation even in post-dilution haemodiafiltration: a cross-over study

Background

While systemic anticoagulation is most widely used in haemodialysis (HD), contraindications to its use might occur in particular settings. The Solacea^™ haemodialyser with an asymmetric triacetate membrane claims improved biocompatibility and has already shown promising results when used in combination with only half dose of anticoagulation. To quantify the performance of the Solacea^™ when further decreasing anticoagulation to zero, fibre blocking was assessed by micro-computed tomography (micro-CT).

Methods

Ten maintenance HD patients underwent six dialysis sessions at midweek using a Solacea^™ 19H dialyser, consecutively in pre-dilution haemodiafiltration (pre-HDF), HD and post-dilution HDF (post-HDF). After the first three sessions with only a quarter of their regular anticoagulation dose (one-quarter), the last three sessions were performed without anticoagulation (zero). Dialyser fibre blocking was quantified in the dialyser outlet potting using a 3D micro-CT scanning technique post-dialysis.

Results

Even in case of reduced (one-quarter) anticoagulation, the relative number of open fibres post-dialysis was almost optimal, i.e. 0.96 (0.87-0.99) with pre-HDF, 0.99 (0.97-0.99) with HD and 0.97 (0.92-0.99) with post-HDF. Fibre patency was mildly decreased for pre-HDF and HD when anticoagulation was decreased from one-quarter to zero, i.e. to 0.76 (0.61-0.85) with pre-HDF (P = 0.004) and to 0.80 (0.77-0.89) with HD (P = 0.013). Comparing the results for zero anticoagulation, post-HDF [i.e. 0.94 (0.82-0.97)] performed as well as HD and pre-HDF.

Conclusions

The Solacea^™ dialyser provides promising results for use in conditions where systemic anticoagulation is contraindicated. Post-HDF, although inducing haemoconcentration in the dialyser, is equally effective for fibre patency in case of zero anticoagulation as pre-HDF and HD when using Solacea^™.

Effect of hemodiafiltration on measured physical activity: primary results of the HDFIT randomized controlled trial

Background

Dialysis patients are typically inactive and their physical activity (PA) decreases over time. Uremic toxicity has been suggested as a potential causal factor of low PA in dialysis patients. Post-dilution high-volume online hemodiafiltration (HDF) provides greater higher molecular weight removal and studies suggest better clinical/patient-reported outcomes compared with hemodialysis (HD).

Methods

HDFIT was a randomized controlled trial at 13 clinics in Brazil that aimed to investigate the effects of HDF on measured PA (step counts) as a primary outcome. Stable HD patients (vintage 3–24 months) were randomized to receive HDF or high-flux HD. Treatment effect of HDF on the primary outcome from baseline to 3 and 6 months was estimated using a linear mixed-effects model.

Results

We randomized 195 patients (HDF 97; HD 98) between August 2016 and October 2017. Despite the achievement of a high convective volume in the majority of sessions and a positive impact on solute removal, the treatment effect HDF on the primary outcome was +538 [95% confidence interval (CI) −330 to 1407] steps/24 h after dialysis compared with HD, and was not statistically significant. Despite a lack of statistical significance, the observed size of the treatment effect was modest and driven by steps taken between 1.5 and 24.0 h after dialysis, in particular between 20 and 24 h (+197 steps; 95% CI −95 to 488).

Conclusions

HDF did not have a statistically significant treatment effect on PA 24 h following dialysis, albeit effect sizes may be clinically meaningful and deserve further investigation.

Impacts of dialysis adequacy and intradialytic hypotension on changes in dialysis recovery time

Background

Dialysis recovery time (DRT) surveys capture the perceived time after HD to return to performing regular activities. Prior studies suggest the majority of HD patients report a DRT > 2 h. However, the profiles of and modifiable dialysis practices associated with changes in DRT relative to the start of dialysis are unknown. We hypothesized hemodialysis (HD) dose and rates of intradialytic hypotension (IDH) would associate with changes in DRT in the first years after initiating dialysis.

Methods

We analyzed data from adult HD patients who responded to a DRT survey ≤180 days from first date of dialysis (FDD) during 2014 to 2017. DRT survey was administered with annual KDQOL survey. DRT survey asks: “How long does it take you to be able to return to your normal activities after your dialysis treatment?” Answers are: < 0.5, 0.5-to-1, 1-to-2, 2-to-4, or > 4 h. An adjusted logistic regression model computed odds ratio for a change to a longer DRT (increase above DRT > 2 h) in reference to a change to a shorter DRT (decrease below DRT < 2 h, or from DRT > 4 h). Changes in DRT were calculated from incident (≤180 days FDD) to first prevalent (> 365-to- ≤ 545 days FDD) and second prevalent (> 730-to- ≤ 910 days FDD) years.

Results

Among 98,616 incident HD patients (age 62.6 ± 14.4 years, 57.8% male) who responded to DRT survey, a higher spKt/V in the incident period was associated with 13.5% (OR = 0.865; 95%CI 0.801-to-0.935) lower risk of a change to a longer DRT in the first-prevalent year. A higher number of HD treatments with IDH episodes per month in the incident period was associated with a 0.8% (OR = 1.008; 95%CI 1.001-to-1.015) and 1.6% (OR = 1.016; 95%CI 1.006-to-1.027) higher probability of a change to a longer DRT in the first- and second-prevalent years, respectively. Consistently, an increased in incidence of IDH episodes/months was associated to a change to a longer DRT over time.

Conclusions

Incident patients who had higher spKt/V and less sessions with IDH episodes had a lower likelihood of changing to a longer DRT in first year of HD. Dose optimization strategies with cardiac stability in fluid removal should be tested.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02187-9.

Online hemodiafilteration use in children: a single center experience with a twist

Background

Haemodiafilteration (HDF) is a promising new modality of renal replacement therapy (RRT). It is an improvement in the quality of hemodialysis (HD) and thus in the quality of patients’lives. The main obstacle to using HDF is the cost, especially in developing countries. The purpose of this study was to evaluate the benefits of incorporating HDF with different regimens in the treatment of children with end stage renal disease (ESRD).

Methods

Thirty-four children with ESRD on regular HD in Pediatric Dialysis Unit, Children’s Hospital, Ain Shams University were followed up in 2 phases: initial phase (all patients: HD thrice weekly for 3 months) and second phase, patients were randomized into 2 groups, HDF group and HD group, the former was subdivided into once and twice weekly HDF subgroups. Evaluation using history, clinical and laboratory parameters at 0, 3, 9 and 18 months was carried out.

Results

On short term, we found that the HDF group was significantly superior to HD group regarding all clinical and laboratory parameters. Also, twice HDF subgroup was significantly superior to once HDF subgroup. This was confirmed on long term follow up, but the once HDF proved comparable to twice subgroup.

Conclusions

Incorporating online hemodiafilteration (OL-HDF) in the RRT of children was beneficial in most of the clinical and laboratory parameters measured. It’s not all or non; OL-HDF, even once a week, can improve outcomes of HD without significantly affecting the cost.

Improvement of clinical outcomes in dialysis: No convincing superiority in dialysis efficacy using hemodiafiltration vs high-flux hemodialysis

Hemodiafiltration (HDF) is not associated with lower mortality risk compared to standard hemodialysis (HD). However, there are many critical clinical outcomes in dialysis patients in addition to mortality; the impact of HDF on these other outcomes is not clear. This retrospective study included all patients referred to DaVita Clinics in the Kingdom of Saudi Arabia. High-flux HD was the initial modality in all patients. Those who did not achieve adequacy targets or those with poorly controlled phosphorus were switched to postdilution HDF using 18 to 23 L exchange per treatment. Patients dialyzing with a central venous catheter, patients who dialyzed less than 90 days at DaVita, and those with interrupted HDF were excluded. Of the 1115 patients, 215 (19%) were on HDF and 900 on high-flux HD; the median follow-up was 6 months for all patients. The HDF group showed a significant reduction in serum phosphate (P < .001), a significant increase in serum calcium (P < .012) and a significant improvement in Kt/V (P < .0001). The HDF group had significantly higher hemoglobin levels than the HD group (P = .024), with a significant reduction in weekly erythropoiesis-stimulating agent dose after starting HDF (P < .001). A modified protocol that included prolonged dialysis duration, larger-sized dialyzer, faster blood flow rates, and adding hemofiltration fluid may be helpful in achieving the recommended targets. Thus, HDF can enable the achievement of adequate dialysis care in some patients. Randomized-controlled clinical trials are necessary to confirm these findings.

Online hemodiafiltration and mortality risk in end-stage renal disease patients: A critical appraisal of current evidence

The life expectancy of end-stage renal disease patients undergoing regular hemodialysis (HD) remains significantly lower than in the general population. Reducing excess mortality by improving renal replacement options is an unmet medical need. Online post-dilution hemodiafiltration (HDF) has been promoted as the gold standard, offering improved clinical outcomes, based on numerous observational studies that suggest a reduced mortality risk and lower morbidity with HDF compared with standard HD. However, most randomized controlled trials (RCTs) have failed to demonstrate a significant beneficial effect of HDF on all-cause mortality. The effects on secondary outcomes were often negligible or absent. Unfortunately, these RCTs were characterized by a moderate to high risk of bias. In post-hoc analyses of the largest RCTs and meta-analysis of individual participant data from four RCTs, HDF patients receiving the highest convection volume consistently and dose-dependently saw superior outcomes. However, as these studies were not designed a priori to clarify this issue, and there are no indisputable mechanisms underlying reduced mortality risks, we cannot exclude the possibility that the health status of patients (with vascular access as a proxy) may affect outcomes more than the convective technique itself. There is currently insufficient evidence to support the contention that high-volume HDF confers relevant benefits to patients over standard HD. The conflicting data of published RCTs reduce confidence in the superiority of high-volume convective therapy. Hopefully, ongoing large RCTs (for example, CONVINCE) may supply an indisputable answer to the crucial question of high-volume HDF.

Techniques to improve intradialytic haemodynamic stability

PURPOSE OF REVIEW

Intra-dialytic hypotension (IDH) remains a significant problem for patients undergoing chronic haemodialysis. IDH causes symptoms that degrade patients' experience, compromises dialysis delivery and is strongly associated with adverse patient outcomes. Greater understanding of the link between IDH and dialysis-induced ischaemia in heart and brain has characterized mechanistic pathways, with repeated episodes of ischaemia resulting in organ dysfunction. This review provides updates from published evidence over the last 2 years across the range of potential interventions for IDH.

RECENT FINDINGS

A literature search was undertaken to identify articles published in peer review journals between January 2016 and April 2018 using terms 'intradialytic hypotension,' 'haemodynamic instability,' 'ESRF,' 'renal replacement therapy,' 'dialysis' in Medline and EMBASE and identified 58 references from which 15 articles were included in this review. Interventions included: cooling the dialysate; sodium profiling; convective therapies; strategies to minimize inter-dialytic weight gain (IDWG) and improve accuracy of target weight assessment; prescribing of antihypertensive medications; and carnitine supplementation.

SUMMARY

IDH remains a significant clinical problem. Recent evidence from the last 2 years does not support any major changes to current practice, with cooling of the dialysate and reduction of IDWG remaining cornerstones of management.

The effect of high-flux hemodialysis and post-dilution hemodiafiltration on platelet closure time in patients with end stage renal disease

INTRODUCTION

We aimed to compare prospectively the effect of high-flux hemodialysis and post-dilution hemodiafiltration on platelets.

METHODS

Twenty-two hemodialysis patients were treated with one high-flux hemodialysis and one post-dilution hemodiafiltration procedure. PFA-100 closure times (collagen/epinephrine-CEPI and collagen/adenosine diphosphate-CADP) were measured before and after the procedure, as well as platelet count, hemoglobin, hematocrit, and red blood cell count. All pre-dialysis and post-dialysis samples were taken from the afferent line.

FINDINGS

The platelet count after vs. before hemodialysis did not change significantly (229.3 ± 55.0 x10⁹ /L vs. 233.6 ± 55.8 × 10⁹ /L; P = 0.269), but was significantly lower after post-dilution hemodiafiltration (215.5 ± 51.7 × 10⁹ /L vs. 245.3 ± 59.9 × 10⁹ /L; P < 0.0001). CEPI after vs. before hemodialysis was not significantly prolonged (192.9 ± 60.8 s vs. 173.4 ± 52.5 s; P = 0.147), and the same applied to CADP (143.6 ± 40.3 s vs. 142.6 ± 38.4 s; P = 0.897). CEPI after vs. before post-dilution hemodiafiltration was significantly prolonged (268.3 ± 41.3 s vs. 176.4 ± 54.0 s; P < 0.0001) as was CADP (221.0 ± 53.9 s vs.133.9 ± 31.1 s; P < 0.0001).

DISCUSSION

Only after post-dilution hemodiafiltration, we found a lower platelet count and prolonged platelet closure times.

Design and methodology of the impact of HemoDiaFIlTration on physical activity and self-reported outcomes: a randomized controlled trial (HDFIT trial) in Brazil

BACKGROUND

End stage renal disease (ESRD) patients require a renal replacement therapy (RRT) to filter accumulated toxins and remove excess water, which are associated with impaired physical function. Hemodialysis (HD) removes middle-molecular weight (MMW) toxins less efficiently compared to hemodiafiltration (HDF); we hypothesized HDF may improve physical function. We detailed the design and methodology of the HDFIT protocol that is testing whether changing from HD to HDF effects physical activity levels and various outcomes.

METHODS

HDFIT is a prospective, multi-center, unblinded, randomized control trial (RCT) investigating the impact of dialysis modality (HDF verses HD) on objectively measured physical activity levels, self-reported quality of life, and clinical/non-clinical outcomes. Clinically stable patients with HD vintage of 3 to 24 months without any severe limitation ambulation were recruited from sites throughout southern Brazil. Eligible patients were randomized in a 1:1 ratio to either: 1) be treated with high volume online HDF for 6 months, or 2) continue being treated with high-flux HD. This study includes run-in and randomization visits (baseline), 3- and 6-month study visits during the interventional period, and a 12-month observational follow up. The primary outcome is the difference in the change in steps per 24 h on dialysis days from baseline to the 6-month follow up in patients treated with HDF versus HD. Physical activity is being measured over one week at study visits with the ActiGraph ( www.actigraphcorp.com ). For assessment of peridialytic differences during the dialysis recovery period, we will analyze granular physical activity levels based on the initiation time of HD on dialysis days, or concurrent times on non-dialysis days and the long interdialytic day.

DISCUSSION

In this manuscript, we provide detailed information about the HDFIT study design and methodology. This trial will provide novel insights into peridialytic profiles of physical activity and various self-reported, clinical and laboratory outcomes in ESRD patients treated by high volume online HDF versus high-flux HD. Ultimately, this investigation will elucidate whether HDF is associated with patients having better vitality and quality of life, and less negative outcomes as compared to HD.

TRIAL REGISTRATION

Registered on ClinicalTrials.gov on 20 April 2016 ( NCT02787161 ).

Effects of Hemodiafiltration versus Conventional Hemodialysis in Children with ESKD: The HDF, Heart and Height Study

BACKGROUND

Hypertension and cardiovascular disease are common in children undergoing dialysis. Studies suggest that hemodiafiltration (HDF) may reduce cardiovascular mortality in adults, but data for children are scarce.

METHODS

The HDF, Heart and Height study is a nonrandomized observational study comparing outcomes on conventional hemodialysis (HD) versus postdilution online HDF in children. Primary outcome measures were annualized changes in carotid intima-media thickness (cIMT) SD score and height SD score.

RESULTS

We enrolled 190 children from 28 centers; 78 on HD and 55 on HDF completed 1-year follow-up. The groups were comparable for age, dialysis vintage, access type, dialysis frequency, blood flow, and residual renal function. At 1 year, cIMT SD score increased significantly in children on HD but remained static in the HDF cohort. On propensity score analysis, HD was associated with a +0.47 higher annualized cIMT SD score compared with HDF. Height SD score increased in HDF but remained static in HD. Mean arterial pressure SD score increased with HD only. Factors associated with higher cIMT and mean arterial pressure SD-scores were HD group, higher ultrafiltration rate, and higher β2-microglobulin. The HDF cohort had lower β2-microglobulin, parathyroid hormone, and high-sensitivity C-reactive protein at 1 year; fewer headaches, dizziness, or cramps; and shorter postdialysis recovery time.

CONCLUSIONS

HDF is associated with a lack of progression in vascular measures versus progression with HD, as well as an increase in height not seen in the HD cohort. Patient-related outcomes improved among children on HDF correlating with improved BP control and clearances. Confirmation through randomized trials is required.

Differences in Dialysis Efficacy Have Limited Effects on Protein-Bound Uremic Toxins Plasma Levels over Time

The protein-bound uremic toxins para-cresyl sulfate (pCS) and indoxyl sulfate (IS) are associated with cardiovascular disease in chronic renal failure, but the effect of different dialysis procedures on their plasma levels over time is poorly studied. The present prospective, randomized, cross-over trial tested dialysis efficacy and monitored pre-treatment pCS and IS concentrations in 15 patients on low-flux and high-flux hemodialysis and high-convective volume postdilution hemodiafiltration over six weeks each. Although hemodiafiltration achieved by far the highest toxin removal, only the mean total IS level was decreased at week three (16.6 ± 12.1 mg/L) compared to baseline (18.9 ± 13.0 mg/L, p = 0.027) and to low-flux dialysis (20.0 ± 12.7 mg/L, p = 0.021). At week six, the total IS concentration in hemodiafiltration reached the initial values again. Concentrations of free IS and free and total pCS remained unaltered. Highest beta₂-microglobulin elimination in hemodiafiltration (p < 0.001) led to a persistent decrease of the plasma levels at week three and six (each p < 0.001). In contrast, absent removal in low-flux dialysis resulted in rising beta₂-microglobulin concentrations (p < 0.001). In conclusion, this trial demonstrated that even large differences in instantaneous protein-bound toxin removal by current extracorporeal dialysis techniques may have only limited impact on IS and pCS plasma levels in the longer term.

Perspectives in renal replacement therapy: Haemodialysis

Haemodialysis (HD) was the first procedure that had demonstrated the ability to partially replace renal function, and became the most widely utilized treatment for patients with end-stage renal disease (ESRD). In a great majority of countries around the world, conventional in-centre HD had become the predominant renal replacement therapy, being touted as able to achieve better solute clearance and more successful in attaining euvolemia than patients on peritoneal dialysis. This is despite the antecedent hemodynamic risks, more rapid loss of residual renal function, greater infectious perils, excessive erythropoietin requirements and higher infrastructure costs. In addition, quality of life had been suggested to be worse among patients on HD, though this had been challenged repeatedly. Consequently, the concept of integrated ESRD care over the last few decades had placed HD, as a complementary rather than a competitive treatment modality to the entire armamentarium of renal replacement therapies. Incorporating HD as part of integrated care into health-care policies and national resource planning will become an essential strategy in improving access and outcome to care among the ESRD population. The improvement in technologies and innovation in prescription had brought forth enhanced dialyzer membrane and machine upgrades, and expanded modalities including more frequent HD and haemodiafiltration. While boasting of controversial improvement in outcomes, many of these therapies remain expensive and insurmountable for widespread utility in many countries. In addition, the results of these new technologies had been conflicting across studies, with some even suggesting that they could be detrimental. Therefore, judicial consideration has to be undertaken to appropriate their use in clinical practice.

Effect of online hemodiafiltration compared with hemodialysis on quality of life in patients with ESRD: A systematic review and meta-analysis of randomized trials

Background

End-stage renal disease (ESRD) is related to high morbidity, mortality, and impaired health-related quality of life. While hemodialysis (HD) is the current life-saving standard of treatment for patients with ESRD, their quality of life (QoL) remains far from desirable. Online HDF (OL-HDF), due to its convenience, could improve the QoL of patients with ESRD, however, this remains uncertain.

Objective

We aimed to assess the body of evidence of OL-HDF compared to HD regarding QoL in patients with ESRD.

Methods

We comprehensively searched in multiple data bases from their inception to February 2018. Reviewers working independently and in duplicate appraised the quality and included randomized controlled trials (RCTs) that evaluated, in patients with ESRD and HD or OL-HDF, QoL (Short Form Health Survey with 36 questions (SF-36) with physical component score (PCS) and mental component score (MCS) as well as scores about social activity, fatigue, and emotion). A meta-analysis of each outcome of interest was performed using a random-effects model.

Results

Six moderate quality RCTs met the inclusion criteria. Meta-analysis of 4 RCTs including a total of 1,209 patients showed that OL-HDF was associated with a lower yet non-significant score of PCS: MD (mean difference) -0.77 (95% CI -1.94 to 0.41, p = 0.20), and MCS: MD -1.25 (95% CI -3.10 to 0.59, p = 0.18); indicating a poorer QoL in patients on OL-HDF. Meta-analysis of 4 RCTs including a total of 845 patients showed OL-HDF was associated with a significant increase in the score of social activity compared to HD: SMD (standardized mean difference): 1.95 (95% CI 0.05 to 3.86, p = 0.04), indicating a better QoL in patients on OL-HDF; but regarding fatigue and emotion, there was no significant improvement when compared to HD by meta-analysis of 3 RCTs (133 patients).

Conclusions

The body of evidence suggests that OL-HDF does not improve QoL in patients with ESRD when compared to HD.

Novel Insights into the Pathogenesis and Prevention of Intradialytic Hypotension

BACKGROUND

Intradialytic hypotension (IDH) is a common complication of haemodialysis (HD) and associated with adverse outcomes, especially when a nadir definition (systolic blood pressure <90 mm Hg) is used. The pathogenesis of IDH is directly linked to the discontinuous nature of the HD treatment, in combination with patient-related factors such as age, diabetes mellitus and cardiac failure.

SUMMARY

Although the decline in blood volume due to removal of fluid by ultrafiltration is the prime mover, thermally induced reflex vasodilation compromises the haemodynamic response to hypovolemia. Recent studies have stressed the relevance of changes in tissue perfusion during HD, which may translate in long-term organ damage. Monitoring changes in tissue perfusion, for which emerging evidence becomes available, appears to have great promise in the fine-tuning of the dialysis procedure. Key Messages: While it is unlikely that IDH can be completely prevented, reduction in inter-dialytic weight gain, prevention of an increase in core temperature by adjusting the dialysate temperature and more frequent or prolonged dialysis treatment remain cornerstones in providing a more comfortable and safe treatment.

Insomnia, muscular cramps and pruritus have low intensity in hemodialysis patients with good dialysis efficiency, low inflammation and arteriovenous fistula

INTRODUCTION

Insomnia, muscular cramps, pruritus and postdialysis recovery time (RT) are quality-of-life parameters that affect hemodialysis (HD) patients physically and mentally.

METHODS

We included 171 end-stage renal disease patients: 115 on high-flux HD and 56 on online hemodiafiltration (HDF). Patients were asked "How long does it take you to recover from a dialysis session?" and they evaluated intensity (absent, mild, medium and severe) of insomnia, muscular cramps and pruritus in the past 4 weeks. We sought associations of RT, insomnia, muscular cramps and pruritus with themselves and age, dialysis vintage, sex, body mass index, hemoglobin, albumin, C-reactive protein (CRP), Daugirdas single-pool Kt/V (Kt/V), ultrafiltration volume, blood processed volume and vascular access type.

RESULTS

Insomnia absence correlated with muscular cramps absence (p = 0.01), arteriovenous fistula (AVF) presence (p = 0.02) and lower CRP (p = 0.003). Muscular cramps absence associated pruritus absence (p = 0.007) and AVF (p = 0.001). Absent pruritus patients were younger (p = 0.04), had higher Kt/V (p = 0.01) and more AVF (p = 0.02). Men insomnia was more severe in HD than HDF and albumin related (p = 0.007), while CRP was lower in absent pruritus. Women insomnia associated with muscular cramps (p = 0.04) and vascular access (p = 0.03), as was pruritus (p = 0.03). RT had no relations with any parameter.

CONCLUSIONS

HD patients with AVF have less insomnia, muscular cramps and pruritus. Insomnia is associated with muscular cramps and inflammation. Pruritus is worse in older patients, is diminished with increased dialysis efficiency and is associated with higher CRP in men. There is no difference between HD and HDF patients, except more severe insomnia for HD in men.