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

Effect of online hemodiafiltration on quality of life, fatigue and recovery time: a systematic review and meta-analysis

The present systematic review and meta-analysis aims to compare the effect of bicarbonate hemodialysis and HDF on quality of life (QoL), fatigue, and time to recovery in end-stage renal disease (ESRD) patients. Searches were run on January 2024 and updated on 3 March 2024 in the following databases: Ovid MEDLINE (1985 to present); Ovid EMBASE (1985 to present); Cochrane Library (Wiley); PubMed (1985 to present). Ten articles were fully assessed for eligibility and included in the investigation. Compared to HD, online HDF had a pooled MD of the mental component score (MCS) of the SF-36 of 0.98 (95% CI - 0.92, 2.87; P = 0.31). and of the physical component score (PCS) of 0.08 (95% CI - 1.32, 1.48; P = 0.91). No significant heterogeneity was observed (Chi2 = 4.85; I2 = 38%; P = 0.18 and Chi2 = 3.85; I2 = 22%; P = 0.28, respectively). Studies that compared the QoL assessed through the Kidney Disease Questionnaire or KDQOL-SF and show that HDF does not improve QoL when compared with HD, in most studies. In five out of seven studies, HDF was not significantly more effective than HD in improving fatigue. The length of the recovery time resulted in similar in patients receiving HDF and HD in all studies included in the present review. HDF is not more effective than HD in improving QoL and fatigue and in reducing the length of time of recovery after dialysis.

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.

Objectively measured daily steps as an outcome in a clinical trial of chronic kidney disease: a systematic review

BACKGROUND

Physical inactivity is prevalent among individuals with chronic kidney disease (CKD) and is linked to unfavorable outcomes. In recent years, daily steps have emerged as a prominent target for interventions in clinical trials. The present study endeavors to scrutinize the effectiveness and/or efficacy of various interventions on daily steps in patients with full-spectrum CKD.

METHODS

In December 2022, a systematic search was conducted across three databases, namely PubMed, Embase, and Web of Science, and subsequently updated in June 2023. The inclusion criteria included randomized controlled studies, quasi-experimental studies, and single-arm trials that assessed an intervention's impact on objectively measured daily steps in patients with chronic kidney disease. The Risk Of Bias In Non-randomized Studies-of Interventions (ROBINS-I) tool was used to assess the risk of bias in non-randomized controlled trials (RCT), while the Cochrane revised tool (ROB-2) was utilized for RCTs.

RESULTS

Seventeen studies were deemed eligible for inclusion in this review, with a focus on examining the efficacy and/or effectiveness of exercise training-based interventions (n = 10), daily step goal-oriented interventions (n = 4), mobile health (mHealth) interventions (n = 1), different dialysis modalities (n = 1), and a "Sit Less, Interact, Move More" intervention (n = 1). The studies exhibit variability in their characteristics and assessment tools, reflecting the findings' heterogeneity. The results indicate that increasing physical activity levels remain challenging, as only a limited number of studies demonstrated significant improvements in participants' daily step counts from baseline to endpoint.

CONCLUSION

Clinical trials with daily steps as an outcome are still lacking in the CKD population. Well-designed clinical trials that objectively assess the physical activity of CKD patients are needed.

Interventions to increase physical activity level in patients with whole spectrum chronic kidney disease: a systematic review and meta-analysis

Background: Little is known about effective interventions to increase physical activity levels in this population. This systematic review and meta-analysis evaluated the effectiveness of different interventions for physical activity levels in whole-spectrum CKD patients.Methods: In this systematic review and meta-analysis, PubMed, Embase, and Web of Science were searched from inception to December 2022, with an update in March 2023. Studies of clinical interventions based on assessing physical activity outcomes (e.g., daily steps, time spent doing physical activity) in patients with whole-spectrum CKD were included. The pooled effect size was calculated using a restricted maximum likelihood method and reported as a standardized mean difference (SMD) with 95% confidence interval (95% CI).Results: The systematic review included 2,156 participants (59.9 ± 8.7 years) from 35 studies. Interventions aimed at modifying physical activity were associated with significantly higher physical activity levels in patients with CKD (SMD = 0.22; 95% CI: 0.08 to 0.36; I2 = 55%). Exercise-based interventions and real-time step feedback increased physical activity by 0.26 (95% CI: 0.07 to 0.45; I2 = 59%) and 0.36 (95% CI: 0.12 to 0.60; I2 = 0%) standard deviations, respectively. Effect sizes did not vary by disease stage or study duration; however, there was evidence of small study or publication bias for the primary analysis.Conclusion: In this systematic review and meta-analysis, intervention strategies aimed at modifying physical activity were associated with significantly increased physical activity levels in patients with whole-spectrum CKD.

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.

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.

Serum Phosphorus Level Rises in US Hemodialysis Patients Over the Past Decade: A DOPPS Special Report

Mineral bone disorder (MBD) is a frequent consequence of chronic kidney disease, more so in patients with kidney failure treated by kidney replacement therapy. Despite the wide availability of interventions to control serum phosphate and parathyroid hormone levels, unmet gaps remain on optimal targets and best practices, leading to international practice pattern variations over time. In this Special Report, we describe international trends from the Dialysis Outcomes and Practice Patterns Study (DOPPS) for MBD biomarkers and treatments from 2002-2021, including data from a group of 7 European countries (Belgium, France, Germany, Italy, Spain, Sweden, United Kingdom), Japan, and the United States. From 2002-2012, mean phosphate levels declined in Japan (5.6 to 5.2 mg/dL), Europe (5.5 to 4.9 mg/dL), and the United States (5.7 to 5.0 mg/dL). Since then, levels rose in the United States (to mean 5.6 mg/dL, 2021), were stable in Japan (5.3 mg/dL), and declined in Europe (4.8 mg/dL). In 2021, 52% (United States), 27% (Europe), and 39% (Japan) had phosphate >5.5 mg/dL. In the United States, overall phosphate binder use was stable (80%-84% over 2015-2021), and parathyroid hormone levels rose only modestly. Although these results potentially stem from pervasive knowledge gaps in clinical practice, the noteworthy steady increase in serum phosphate in the United States over the past decades may be consequential to patient outcomes, an uncertainty that hopefully will soon be addressed by ongoing clinical trials. The DOPPS will continue to monitor international trends as new interventions and strategies ensue for MBD management in chronic kidney disease.

Continuous Long-Term Physical Activity Monitoring in Hemodialysis Patients

Background

Physical inactivity is common in patients receiving hemodialysis, but activity patterns throughout the day and in relation to dialysis are largely unknown. This knowledge gap can be addressed by long-term continuous activity monitoring, but this has not been attempted and may not be acceptable to patients receiving dialysis.

Methods

Ambulatory patients with end-stage kidney disease receiving thrice-weekly hemodialysis wore commercially available wrist-worn activity monitors for 6 months. Step counts were collected every 15 minutes and were linked to dialysis treatments. Physical function was assessed using the Short Physical Performance Battery (SPPB). Fast time to recovery from dialysis was defined as ≤2 hours. Mixed effects models were created to estimate step counts over time.

Results

Of 52 patients enrolled, 48 were included in the final cohort. The mean age was 60 years, and 75% were Black or Hispanic. Comorbidity burden was high, 38% were transported to and from dialysis by paratransit, and 79% had SPPB <10. Median accelerometer use (199 days) and adherence (95%) were high. Forty-two patients (of 43 responders) reported wearing the accelerometer every day, and few barriers to adherence were noted. Step counts were lower on dialysis days (3991 [95% CI, 3187 to 4796] versus 4561 [95% CI, 3757 to 5365]), but step-count intensity was significantly higher during the hour immediately after dialysis than during the corresponding time on nondialysis days (188 steps per hour increase [95% CI, 171 to 205]); these levels were the highest noted at any time. Postdialysis increases were more pronounced among patients with fast recovery time (225 [95% CI, 203 to 248] versus 134 [95% CI, 107 to 161] steps per hour) or those with SPPB ≥7. Estimates were unchanged after adjustment for demographics, diabetes status, and ultrafiltration rate.

Conclusions

Long-term continuous monitoring of physical activity is feasible in patients receiving hemodialysis. Highly granular data collection and analysis yielded new insights into patterns of activity after dialysis treatments.

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.

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.

High-volume hemodiafiltration decreases the pre-dialysis concentrations of indoxyl sulfate and p-cresyl sulfate compared to hemodialysis: a post-hoc analysis from the HDFit randomized controlled trial

BACKGROUND

Although high-volume online hemodiafiltration has been associated with higher clearance and lower pre-dialysis concentration of middle molecular weight toxins compared to hemodialysis, its effect on protein-bound uremic toxins has shown inconclusive results. In this study, we investigated whether hemodiafiltration impacts pre-dialysis plasma levels of the toxins indoxyl sulfate, p-cresyl sulfate, and indole-3-acetic acid compared to high-flux hemodialysis.

METHODS

This is a post-hoc analysis of the multicenter, randomized controlled trial HDFit (ClinicalTrials.gov: NCT02787161). Uremic toxins were determined by high performance liquid chromatography at baseline, 3, and 6 months. Mean differences in monthly changes of pre-dialysis uremic toxin concentrations between hemodiafiltration and high-flux hemodialysis were analyzed using linear mixed-effect models.

RESULTS

One hundred ninety-three patients (mean age 53 years old, 71% males) were analyzed. There were no differences between groups regarding clinical and biochemical characteristics at baseline or duration of dialysis session and blood flows throughout the follow-up. Mean differences in rates of change (μM/month, [confidence interval CI]) in high-flux hemodialysis vs. hemodiafiltration were 2.4 [0.3 to 4.56], 3.94 [- 1.54 to 9.41] and 0.06 [- 0.6 to 0.5] for indoxyl sulfate, p-cresyl sulfate and indole-3-acetic acid, respectively. In the exploratory analysis, these differences in high-flux hemodialysis vs. hemodiafiltration subgroup with convective volume > 27.5 L were 2.86 [0.43 to 5.28], 7.43 [0.7 to 14.16] and - 0.19 [- 0.88 to 0.50].

CONCLUSION

These exploratory findings suggest that hemodiafiltration is more effective in reducing indoxyl sulfate as compared to standard high-flux hemodialysis, and also that this effect was extended to p-cresyl sulfate in patients achieving higher convective volumes.

Daily Step Counts in Patients With Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Observational Studies

Background

Physical inactivity is an essential factor in the prognosis of patients with chronic kidney disease (CKD). Daily step count is a straightforward measure to assess physical activity levels. Understanding the step counts among different CKD stages is essential to change sedentary behavior.

Objectives

This systematic review and meta-analysis aimed to investigate the daily step counts in patients with CKD at a different stage.

Design

A systematic review and meta-analysis.

Data Sources

The literature search was performed in PubMed, Embase, and Web of Science from inception to November 3rd, 2021.

Review Methods

Observational studies (cross-sectional, case-control, or cohort studies) reported specific values of step counts in CKD patients by the wearable device were included. A random-effects model was used to pool the data. Subgroup analysis explored differences in outcomes by stage of CKD. Heterogeneity between studies was assessed using the χ2 test of Cochrane's Q statistic. A contour-enhanced funnel plot was conducted to investigate publication bias. Univariate and multivariate meta-regression was conducted to examine possible sources of heterogeneity.

Results

Twenty-eight articles were identified and used for quantitative analysis. The result showed that the daily step count in patients with CKD was 4642.47 (95% CI: 4274.18–5010.76), and significantly lower than the healthy population. Subgroup analysis revealed that the step counts decreased before dialysis, dropped to a freezing point at the hemodialysis phase, and increased after kidney transplantation. Meta-regression analysis showed that daily step counts were relatively higher in the Americas or younger than 60 or kidney transplant recipients.

Conclusion

The status of daily step counts in patients with CKD decreases with CKD severity and increases after kidney transplantation. Although studies have begun to focus on strategies to improve step counts in patients with CKD, future studies should focus more on step counts in pre-dialysis patients and changing their physically inactive lifestyle early to alleviate deteriorating renal function.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=291551, identifier: CRD42021291551.

The Role of Physical Activity and Mortality in Hemodialysis Patients: A Review

Available data indicated that physical activity was related to improved outcomes in hemodialysis patients. Multiple observational studies involving different cohorts have reported that increased physical activity level was associated with decreased mortality among hemodialysis patients. Therefore, promoting physical activity has become an increasingly critical and promising approach to improving cardiovascular health and clinical outcomes in hemodialysis patients. This review summarizes the published articles regarding physical activity and hemodialysis patients, focusing on mortality and strategy to promote physical activity.

CONVINCE in the context of existing evidence on haemodiafiltration

Haemodiafiltration (HDF) provides a greater removal of larger solutes and protein-bound compounds than conventional high-flux haemodialysis (HD). There are indications that the patients receiving the highest convection volumes of HDF result in an improved survival compared with HD. However, the comparative efficacy of HDF vs HD remains unproven. Here we provide a comparative account of the methodology and aims of ‘the comparison of high-dose HDF with high-flux HD’ (CONVINCE) study in the context of the totality of evidence and how this study will contribute to reaching a higher level of certainty regarding the comparative efficacy of HDF vs HD in people with end-stage kidney disease (ESKD).

Effect of Hemodiafiltration Versus Hemodialysis on Cognitive Function Among Patients With End-Stage Renal Disease: A Multicenter Study

Background: Cognitive impairment (CI) and dementia are common in patients with end-stage renal disease (ESRD) undergoing hemodialysis. Their cause is multifactorial. Our study is first to compare the impact of hemodialysis (HD) and online hemodiafiltration (HDF) on patients’ cognitive outcomes.

Methods: This was a cross sectional, multicenter cohort study. Adult ESRD patients aged >18 years on regular high flux HD or online HDF were recruited in the study. Clinical, laboratory, daily activities and cognitive functions assessment were assessed in all the involved individuals.

Results: A total of 241 patients were successfully recruited into the study: 164 treated with high flux HD and 77 treated with HDF. Hypertension and diabetes were the commonest associated comorbidities. 85.9% of patients were functionally independent with no significant difference between those on HD versus HDF. 81.3% of our patients showed different degrees of CI. HDF has no superiority in the improvement of cognitive functions. Age, vitamin D level and haemoglobin (Hb) were the most independent predictors of cognitive function impairment among HD patients.

Conclusions: Cognitive function impairment is a common problem in hemodialysis and is associated with multiple risk factors. HDF showed no beneficial effect over HD. There is no superiority of online HDF versus high flux HD in improving cognitive functions.

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.

Digital health and artificial intelligence in kidney research: a report from the 2020 Kidney Disease Clinical Trialists (KDCT) meeting

The exponential growth in digital technology coupled with the global COVID-19 pandemic is driving a profound change in the delivery of medical care and research conduct. The growing availability of electronic monitoring, electronic health records, smartphones and other devices, and access to ever greater computational power, provides new opportunities, but also new challenges. Artificial intelligence (AI) exemplifies the potential of this digital revolution, which also includes other tools such as mobile health (mHealth) services and wearables. Despite digital technology becoming commonplace, its use in medicine and medical research is still in its infancy, with many clinicians and researchers having limited experience with such tools in their usual practice. This paper, derived from the 'Digital Health and Artificial Intelligence' session of the Kidney Disease Clinical Trialists virtual workshop held in September 2020, aims to illustrate the breadth of applications to which digital tools and AI can be applied in clinical medicine and research. It highlights several innovative projects incorporating digital technology that range from streamlining medical care of those with acute kidney injury to the use of AI to navigate the vast genomic and proteomic data gathered in kidney disease. Important considerations relating to any new digital health project are presented, with a view to encouraging the further evolution and refinement of these new tools in a manner that fosters collaboration and the generation of robust evidence.

Achieving high convective volume in hemodiafiltration: Lessons learned after successful implementation in the HDFit trial

BACKGROUND AND OBJECTIVES

High-volume online hemodiafiltration (OL-HDF) associates with improved outcomes compared to hemodialysis (HD), provided adequate dosing is achieved as estimated from convective volume (CV). Achievement of high CV and its impact on biochemical indicators following a standardized protocol converting HD patients to OL-HDF has not been systematically reported. We assessed the success of implementation of OL-HDF in clinics naïve to the modality.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We analyzed the results of the implementation of postdilution OL-HDF in patients randomized to the HDF arm of a clinical trial (impact of hemoDiaFIlTration on physical activity and self-reported outcomes: a randomized controlled trial (HDFit) trial [ClinicalTrials.gov:NCT02787161]). The day before randomization of the first patient to OL-HDF at each clinic staff started a 3-day in-person training module on operation of Fresenius 5008 CorDiax machine in HDF mode. Patients were converted from high-flux HD to OL-HDF under oversight of trainers. OL-HDF was performed over a 6-months follow-up with a CV target of 22 L/treatment. We characterized median achieved CV >22 L/treatment record and analyzed the impact of HDF on biochemical variables.

RESULTS

Ninety-seven patients (mean age 53 ± 16 years, 29% with diabetes, and 11% had a catheter) from 13 clinics randomized to the OL-HDF arm of the trial were converted from HD to HDF. Median CV > 22 L/treatment was achieved in 99% (94/95) of OL-HDF patients throughout follow-up. Monthly mean CV ranged from 27.1 L to 27.5 L. OL-HDF provided an increased single pool Kt/V at 3-months (0.2 [95% CI: 0.1-0.3]) and 6-months (0.2 [95% CI: 0.1-0.4]) compared to baseline, and reduced phosphate at 3-months (-0.4 mg/dL [95% CI: -0.8 to -0.12]) of follow-up.

CONCLUSIONS

High-volume online hemodiafiltration was successfully implemented with 99% of patients achieving protocol defined CV target. Monthly mean CV was consistently >22 L/treatment during follow-up. Kt/V increased, and phosphate decreased with OL-HDF. Findings resulting from a short training period in several dialysis facilities appear to suggest HDF is an easily implementable technique.