The Impact of Exercising During Haemodialysis on Blood Pressure, Markers of Cardiac Injury and Systemic Inflammation--Preliminary Results of a Pilot Study

Effects of Exercise on Inflammatory Markers in Individuals with Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Individuals with chronic kidney disease (CKD) have a systemic inflammatory state. We assessed the effects of exercise on inflammatory markers in individuals with CKD. An electronic search was conducted, including MEDLINE. Experimental clinical trials that investigated the effects of exercise on inflammatory markers in individuals with CKD at all stages were included. Meta-analyses were conducted using the random-effects model and standard mean difference (SMD). Subgroup analyses were performed for resistance, aerobic, and combined exercise interventions. Twenty-nine studies were included in the meta-analyses. Exercise interventions showed significant reductions in C-reactive protein (CRP) (SMD: -0.23; 95% CI: -0.39 to -0.06), interleukin (IL)-6 (SMD: -0.35; 95% CI: -0.57, -0.14), and tumor necrosis factor-alpha (TNF-α) (SMD: -0.63, 95% CI: -1.01, -0.25) when compared with the controls. IL-10 levels significantly increased (SMD: 0.66, 95% CI: 0.09, 1.23) with exercise interventions. Resistance interventions significantly decreased CRP (SMD: -0.39, 95% CI: -0.69, -0.09) and TNF-α (SMD: -0.72, 95% CI: -1.20, -0.23) levels, while increasing IL-10 levels (SMD: 0.57, 95% CI: 0.04, 1.09). Aerobic interventions only significantly reduced IL-6 levels (SMD: -0.26, 95% CI: -0.51, -0.01). No significant changes in any inflammatory markers were observed with combined exercise interventions. Exercise interventions are effective as an anti-inflammatory therapy in individuals with CKD compared to usual care control groups. Resistance interventions seem to promote greater anti-inflammatory effects.

A Randomized Trial Examining the Impact of Timing of Intradialytic Cycling on Intradialytic Hypotension

Introduction

Intradialytic cycling is often performed during the first half of hemodialysis because of concerns regarding increased frequency of intradialytic hypotension (IDH) late in hemodialysis. This increases exercise program resource needs and limits utility of intradialytic cycling to treat dialysis-related symptoms.

Methods

This multicenter, randomized, crossover trial compared IDH rate when cycling during the first half versus the second half of hemodialysis in 98 adults on maintenance hemodialysis. Group A cycled during the first half of hemodialysis for 2 weeks and subsequently during the second half for 2 weeks. In group B, the cycling schedule was reversed. Blood pressure (BP) was measured every 15 minutes throughout hemodialysis. Primary outcome was IDH rate (systolic BP [SBP] decrease of >20 mm Hg or SBP <90 mm Hg). Secondary outcomes included symptomatic IDH rate and time to recover post hemodialysis. Data were analyzed using negative binomial and gamma distribution mixed regression.

Results

Mean age 64.7 (SD 12.0) and 64.7 (SD 14.2) years in group A (n = 52) and group B (n = 46), respectively. Proportions of females were 33% in group A and 43% in group B. Median time on hemodialysis was 4.1 (interquartile range [IQR] 2.5, 6.1]) years in group A and 3.9 years (IQR 2.5, 6.7) in group B. IDH rate per 100 hemodialysis hours (95% confidence interval [CI]) was 34.2 (26.4, 42.0) and 36.0 (28.9, 43.1) during early and late intradialytic cycling, respectively (P = 0.53). Timing of intradialytic cycling was not associated with symptomatic IDH (relative risk [RR]: 1.07 [0.75-1.53]) or time to recover post hemodialysis (odds ratio: 0.99 [0.79-1.23]).

Conclusion

We found no association between the rate of overall or symptomatic IDH and the timing of intradialytic cycling in patients enrolled in an intradialytic cycling program. Increased use of cycling late in hemodialysis may optimize intradialytic cycling program resource use and should be studied as a possible treatment for symptoms common in late hemodialysis.

Melatonin intake before intradialytic exercise reverses oxidative stress and improves antioxidant status in hemodialysis patients

PURPOSE

The present study aimed to investigate for the first time the effects of melatonin (MEL) intake on oxidative stress and cellular damage during intradialytic exercise (IEX).

METHODS

Thirteen hemodialysis (HD) patients volunteered to participate in the current randomized crossover trial. Participants performed four HD sessions in four different conditions: (Exercise (EX)-MEL), (EX-Placebo (PLA)), (Control (C)-MEL), and (C-PLA). 3 mg of MEL or PLA were taken 60 min before starting exercise, or at the equivalent time in the C conditions. Blood samples were taken before HD (T0), immediately after the end of IEX (T1), 60 min after IEX (T2), or at the corresponding times in the C conditions to measure free radicals damage, antioxidant biomarkers, as well as biomarkers of muscle and liver damage.

RESULTS

Malondialdehyde and Advanced Oxidation Protein Products decreased in (C-MEL) (p < 0.05, d = 2.19; p < 0.01, d = 0.99, respectively) at T2 compared to T0. Catalase and total thiol levels increased in (C-MEL) (p < 0.01, d = 1.51; p < 0.01, d = 1.56, respectively) and in (EX-MEL) (p = 0.01, d = 1.28; p < 0.01, d = 1.52, respectively) at T1 compared to T0. Total bilirubin levels increased in (EX-MEL) and (C-MEL) at T2 compared to T0 (p < 0.001, d = 2.77; p < 0.001, d = 1.36, respectively), but only at T2 compared to T1 in (EX-MEL) (p < 0.001, d = 1.67). In all conditions, uric acid levels decreased at T1 compared to T0 and at T2 compared to T1, while biomarkers of muscle and liver damage remained unchanged.

CONCLUSION

This pilot study is the first to show that MEL ingestion, alone or combined with IEX, could improve oxidant-antioxidant balance during HD.

An update review on hemodynamic instability in renal replacement therapy patients

BACKGROUND

Hemodynamic instability in patients undergoing kidney replacement therapy (KRT) is one of the most common and essential factors influencing mortality, morbidity, and the quality of life in this patient population.

METHOD

Decreased cardiac preload, reduced systemic vascular resistance, redistribution of fluids, fluid overload, inflammatory factors, and changes in plasma osmolality have all been implicated in the pathophysiology of hemodynamic instability associated with KRT.

RESULT

A cascade of these detrimental mechanisms may ultimately cause intra-dialytic hypotension, reduced tissue perfusion, and impaired kidney rehabilitation. Multiple parameters, including dialysate composition, temperature, posture during dialysis sessions, physical activity, fluid administrations, dialysis timing, and specific pharmacologic agents, have been studied as possible management modalities. Nevertheless, a clear consensus is not reached.

CONCLUSION

This review includes a thorough investigation of the literature on hemodynamic instability in KRT patients, providing insight on interventions that may potentially minimize factors leading to hemodynamic instability.

Hemodynamic Tolerance of Virtual Reality Intradialysis Exercise Performed during the Last 30 Minutes versus the Beginning of the Hemodialysis Session

Background: Exercise improves the physical function of people suffering from chronic kidney disease on hemodialysis (HD). Virtual reality is a new type of intradialysis exercise that has a positive impact on physical function. Intradialysis exercise is recommended during the first 2 h, but its safety in the last part of the dialysis session is unknown. Methods: This was a pilot sub-study of a clinical trial. Several hemodynamic control variables were recorded, including blood pressure, heart rate, and intradialytic hypotensive events. These variables were recorded during three different HD sessions, one HD session at rest, another HD session with exercise during the first two hours, and one HD session with exercise during the last 30 min of dialysis. The intradialysis virtual reality exercise was performed for a maximum of 30 min. Results: During exercise sessions, there was a significant increase in heart rate (6.65 (4.92, 8.39) bpm; p < 0.001) and systolic blood pressure (6.25 (0.04,12.47) mmHg; p < 0.05). There was no difference in hemodynamic control between the sessions with exercise during the first two hours and the sessions with exercise during the last 30 min. There was no association between intra-dialytic hypotensive events at rest (five events) or exercise at any point (two vs. one event(s), respectively). Conclusion: performing exercise with virtual reality at the end of a hemodialysis session is not associated with hemodynamic instability.

The effectiveness of intradialytic exercise in ameliorating fatigue symptoms in patients with chronic kidney failure undergoing hemodialysis: A systematic literature review and meta-analysis

Objective

Hemodialysis in patients with chronic kidney failure is an intervention serving as an alternative to kidney transplantation. In 2019, chronic kidney failure became the world's 6th leading cause of death. In Indonesia, kidney failure has an increasing number of cases every year and is the 10th highest cause of death. According to basic health research in 2018, the prevalence of chronic kidney failure was 3.4%, and 19.3% of patients 15 years of age and older underwent hemodialysis. This study analyzed the effectiveness of intradialytic exercise in ameliorating fatigue symptoms in patients with chronic kidney failure undergoing hemodialysis, in terms of exercise type, duration, time, and frequency.

Methods

All appropriate and eligible full-text articles published between January 2010 and October 2021 were screened and extracted from the databases PubMed, Scopus, ProQuest, Science Direct, CrossRef, Google Scholar, and Garuda Database for Research and Technology. The articles were critically reviewed, and two independent authors reviewed the risk of bias by using the JBI form. Data analysis was performed qualitatively to obtain an overview of the characteristics of intradialytic exercise and quantitatively through meta-analysis.

Results

Intradialytic exercise was found to effectively decrease fatigue by 81% in the intervention group. The most significant effect sizes were as follows: type of intradialytic exercise: aerobic exercise (146%); duration of intradialytic exercise: >20 min (100%); time of intradialytic exercise: first 2 h (127%); and exercise frequency: <12 sessions (120%).

Conclusion

The characteristics of intradialytic exercise that are considered effective in ameliorating fatigue are aerobic exercise lasting >20 min and performed in the first 2 h of hemodialysis, with a frequency of <12 sessions.

Effect of Exercise on Inflammation in Hemodialysis Patients: A Systematic Review

Background: In recent years, physical exercise has been investigated for its potential as a therapeutic tool in patients with end-stage renal disease (ESRD) undergoing hemodialysis maintenance treatment (HD). It has been shown that regular practice of moderate-intensity exercise can improve certain aspects of immune function and exert anti-inflammatory effects, having been associated with low levels of pro-inflammatory cytokines and high levels of anti-inflammatory cytokines. Purpose: The aim of this review is to examine the studies carried out in this population that analyzed the effect of intradialytic exercise on the inflammatory state and evaluate which exercise modality is most effective. Methods: The search was carried out in the MEDLINE, CINAHL Web of Science and Cochrane Central Register of Controlled Trials databases from inception to June 2022. The PEDro scale was used to assess methodological quality, and the Cochrane Risk of Bias Tool and MINORS were used to evaluate the risk of bias. The quality of evidence was assessed with GRADE scale. The outcome measures were systemic inflammation biomarkers. Results: Mixed results were found in terms of improving inflammation biomarkers, such as CRP, IL-6 or TNFα, after exercise. Aerobic exercise seems to improve systemic inflammation when performed at medium intensity while resistance training produced better outcomes when performed at high intensity. However, some studies reported no differences after exercise and these results should be taken with caution. Conclusions: The low quality of the evidence suggests that aerobic and resistance exercise during HD treatment improves systemic inflammation biomarkers in patients with ESRD. In any case, interventions that increase physical activity in patients with ESRD are of vital importance as sedentary behaviors are associated with mortality. More studies are needed to affirm solid conclusions and to make intervention parameters, such as modality, dose, intensity or duration, sufficiently clear.

Exercise training for adults undergoing maintenance dialysis

BACKGROUND

Dialysis treatments weigh heavily on patients' physical and psychosocial health. Multiple studies have assessed the potential for exercise training to improve outcomes in adults undergoing dialysis. However, uncertainties exist in its relevance and sustainable benefits for patient-important outcomes. This is an update of a review first published in 2011.

OBJECTIVES

To assess the benefits and safety of regular structured exercise training in adults undergoing dialysis on patient-important outcomes including death, cardiovascular events, fatigue, functional capacity, pain, and depression. We also aimed to define the optimal prescription of exercise in adults undergoing dialysis.

SEARCH METHODS

In this update, we conducted a systematic search of the Cochrane Kidney and Transplant Register of Studies up to 23 December 2020. The Register includes studies identified from CENTRAL, MEDLINE, EMBASE, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov as well as kidney-related journals and the proceedings of major kidney conferences.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of any structured exercise programs of eight weeks or more in adults undergoing maintenance dialysis compared to no exercise or sham exercise.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the search results for eligibility, extracted the data and assessed the risk of bias using the Cochrane risk of bias tool. Whenever appropriate, we performed random-effects meta-analyses of the mean difference in outcomes. The primary outcomes were death (any cause), cardiovascular events and fatigue. Secondary outcomes were health-related quality of life (HRQoL), depression, pain, functional capacity, blood pressure, adherence to the exercise program, and intervention-related adverse events.

MAIN RESULTS

We identified 89 studies involving 4291 randomised participants, of which 77 studies (3846 participants) contributed to the meta-analyses. Seven studies included adults undergoing peritoneal dialysis. Fifty-six studies reported aerobic exercise interventions, 21 resistance exercise interventions and 19 combined aerobic and resistance training within the same study arm. The interventions lasted from eight weeks to two years and most often took place thrice weekly during dialysis treatments. A single study reported death and no study reported long-term cardiovascular events. Five studies directly assessed fatigue, 46 reported HRQoL and 16 reported fatigue or pain through their assessment of HRQoL. Thirty-five studies assessed functional capacity, and 21 reported resting peripheral blood pressure. Twelve studies reported adherence to exercise sessions, and nine reported exercise-related adverse events. Overall, the quality of the included studies was low and blinding of the participants was generally not feasible due to the nature of the intervention. Exercise had uncertain effects on death, cardiovascular events, and the mental component of HRQoL due to the very low certainty of evidence. Compared with sham or no exercise, exercise training for two to 12 months may improve fatigue in adults undergoing dialysis, however, a meta-analysis could not be conducted. Any exercise training for two to 12 months may improve the physical component of HRQoL (17 studies, 656 participants: MD 4.12, 95% CI 1.88 to 6.37 points on 100 points-scale; I² = 49%; low certainty evidence). Any exercise training for two to 12 months probably improves depressive symptoms (10 studies, 441 participants: SMD -0.65, 95% CI -1.07 to -0.22; I² = 77%; moderate certainty evidence) and the magnitude of the effect may be greater when maintaining the exercise beyond four months (6 studies, 311 participants: SMD -0.30, 95% CI 0.14 to -0.74; I² = 71%). Any exercise training for three to 12 months may improve pain (15 studies, 872 participants: MD 5.28 95% CI -0.12 to 10.69 points on 100 points-scale; I² = 63%: low certainty evidence) however, the 95% CI indicates that exercise training may make little or no difference in the level of pain. Any exercise training for two to six months probably improves functional capacity as it increased the distance reached during six minutes of walking (19 studies, 827 participants: MD 49.91 metres, 95% CI 37.22 to 62.59; I² = 34%; moderate certainty evidence) and the number of sit-to-stand cycles performed in 30 seconds (MD 2.33 cycles, 95% CI 1.71 to 2.96; moderate certainty evidence). There was insufficient evidence to assess the safety of exercise training for adults undergoing maintenance dialysis. The results were similar for aerobic exercise, resistance exercise, and a combination of both aerobic and resistance exercise.

AUTHORS' CONCLUSIONS

It is uncertain whether exercise training improves death, cardiovascular events, or the mental component of HRQoL in adults undergoing maintenance dialysis. Exercise training probably improves depressive symptoms, particularly when the intervention is maintained beyond four months. Exercise training is also likely to improve functional capacity. Low certainty evidence suggested that exercise training may improve fatigue, the physical component of quality of life, and pain. The safety of exercise training for adults undergoing dialysis remains uncertain.

Intradialytic cycling does not exacerbate microparticles or circulating markers of systemic inflammation in haemodialysis patients

Purpose

Patients receiving haemodialysis (HD) display elevated circulating microparticle (MP) concentration, tissue factor (TF) expression and markers of systemic inflammation, though regular intradialytic cycling (IDC) may have a therapeutic effect. This study investigated the impact of regular, moderate-intensity IDC on circulating MPs and inflammatory markers in unit-based HD patients.

Methods

Patients were cluster-randomised to intervention (n = 20, age: 51.4 ± 18.1 years, body mass: 77.6 ± 18.3 kg, mean ± SD) or no-exercise control (n = 20, 56.8 ± 14.0 years, 80.5 ± 26.5 kg). Intervention participants completed 30 min of moderate intensity (rating of perceived exertion [RPE] of 12–14) IDC, thrice weekly for 6 months. Pre-dialysis venous blood samples were obtained at 0, 3 and 6 months. Circulating MP phenotypes, cytokines, chemokine and MP TF expression were quantified using flow cytometry and cytometric bead array assays.

Results

Despite high exercise compliance (82%), no IDC-dependent effects were observed for any MP, cytokine or chemokine measure (p ≥ 0.051, η_ρ² ≤ 0.399) other than TNF-α (p = 0.001, η_ρ² = 0.186), though no significance was revealed upon post hoc analysis.

Conclusion

Six months of regular, moderate-intensity IDC had no effect on MPs, cytokines or chemokines. This suggests that the exercise did not exacerbate thrombotic or inflammatory status, though further functional assays are required to confirm this.

Trial registration

ISRCTN1129707, prospectively registered on 05/03/2015.

Spinning the legs and blood: should intradialytic exercise be routinely offered during maintenance haemodialysis?

Patients with end-stage kidney disease on haemodialysis (HD) have an elevated risk of cardiovascular disease (CVD). These patients also experience high levels of physical deconditioning and programmes of rehabilitation have been tested in a variety of forms with variable success. It has been suggested that programmes of exercise rehabilitation have a role to play in improving the physical condition of patients on HD and in addressing the traditional and non-traditional risk factors that drive CVD for this population. Intradialytic exercise has often been suggested as a convenient way of delivering rehabilitation for patients on HD, as it makes use of otherwise dead time, but there are legitimate concerns about this group of at-risk patients undertaking exercise at a time when their myocardium is already vulnerable to the insults of demand ischaemia from the processes of dialysis and ultrafiltration. A study in this issue of Clinical Kidney Journal provides reassuring data, showing that cycling during dialysis potentially reduces evidence of demand ischaemia (episodes of myocardial stunning). Together with the safety and quality of life data, we expect from the multicentre PrEscription of Intra-Dialytic Exercise to Improve quAlity of Life in Patients With Chronic Kidney Disease study (the protocol for which is published concurrently), rehabilitation programmes that include intradialytic exercise are perhaps closer than ever for patients on HD.

Cardiopulmonary and metabolic physiology during hemodialysis and inter/intradialytic exercise

Hemodialysis is associated with numerous symptoms and side effects that, in part, may be due to subclinical hypoxia. However, acute cardiopulmonary and metabolic physiology during hemodialysis is not well defined. Intradialytic and interdialytic exercise appear to be beneficial and may alleviate these side effects. To better understand these potential benefits, the acute physiological response to exercise should be evaluated. The aim of this study was to compare and characterize the acute physiological response during hemodialysis, intradialytic exercise, and interdialytic exercise. Cardiopulmonary physiology was evaluated during three conditions: 1) hemodialysis without exercise (HD), 2) intradialytic exercise (IDEx), and 3) interdialytic exercise (Ex). Exercise consisted of 30-min constant load cycle ergometry at 90% V̇O₂AT (anaerobic threshold). Central hemodynamics (via noninvasive bioreactance) and ventilatory gas exchange were recorded during each experimental condition. Twenty participants (59 ± 12 yr, 16/20 male) completed the protocol. Cardiac output (Δ = -0.7 L/min), O₂ uptake (Δ = -1.4 mL/kg/min), and arterial-venous O₂ difference (Δ = -2.0 mL/O₂/100 mL) decreased significantly during HD. Respiratory exchange ratio exceeded 1.0 throughout HD and IDEx. Minute ventilation was lower (P = 0.001) during IDEx (16.5 ± 1.1 L/min) compared with Ex (19.8 ± 1.0 L/min). Arterial-venous O₂ difference was partially restored further to IDEx (4.6 ± 1.9 mL/O₂/100 mL) compared with HD (3.5 ± 1.2 mL/O₂/100 mL). Hemodialysis altered cardiopulmonary and metabolic physiology, suggestive of hypoxia. This dysregulated physiology contributed to a greater physiological demand during intradialytic exercise compared with interdialytic exercise. Despite this, intradialytic exercise partly normalized cardiopulmonary physiology during treatment, which may translate to a reduction in the symptoms and side effects of hemodialysis.NEW & NOTEWORTHY This study is the first, to our knowledge, to directly compare cardiopulmonary and metabolic physiology during hemodialysis, intradialytic exercise, and interdialytic exercise. Hemodialysis was associated with increased respiratory exchange ratio, blunted minute ventilation, and impaired O₂ uptake and extraction. We also identified a reduced ventilatory response during intradialytic exercise compared with interdialytic exercise. Impaired arterial-venous O₂ difference during hemodialysis was partly restored by intradialytic exercise. Despite dysregulated cardiopulmonary and metabolic physiology during hemodialysis, intradialytic exercise was well tolerated.

Melatonin ingestion before intradialytic exercise improves immune responses in hemodialysis patients

PURPOSE

The present study aimed to investigate the effects of melatonin (MEL) intake on systemic inflammation and immune responses during intradialytic exercise.

METHODS

Thirteen hemodialysis (HD) patients volunteered to participate in the current randomized-crossover study. Immunological responses were monitored in four HD sessions at different conditions: [Exercise (EX) + MEL], [EX + Placebo (PLA)], [Control (CON) + MEL] and [CON + PLA]. MEL (3 mg) or PLA was ingested 1 h before starting exercise or the equivalent time in CON condition. During all sessions, peripheral blood samples were collected to assess c-reactive protein, complete blood count, and immune cells phenotypes before HD (T0), immediately after exercise (T1) and 1 h after exercise (T2) or at corresponding times in the CON condition.

RESULTS

HD therapy induced a significant decrease in natural killer (NK) (p = 0.001, d = 0.85; p < 0.001, d = 1.19, respectively) and CD8⁺ T-lymphocytes rates (p = 0.001, d = 0.57; p < 0.001, d = 0.75, respectively) at T1 and T2 compared to T0. MEL intake prevented the decrease in NK and CD8⁺ T-lymphocytes, increased the proportion of CD4⁺ T-lymphocytes at T1 and T2 compared to T0 (p = 0.002, d = 1.18; p = 0.001, d = 1.04, respectively) and decreased the proportion of CD14⁺⁺CD16⁺ Monocytes at T2 compared to T0 (p = 0.02, d = 1.57) in peripheral blood during HD therapy. Similar results were found in [EX + MEL] and [EX + PLA] conditions.

CONCLUSION

This pilot study provides the first evidence that MEL intake alone or associated with intradialytic exercise displays potential immunoregulatory and anti-inflammatory effects. The combination of MEL with intradialytic exercise may be an appropriate anti-inflammatory therapy for HD patients.

Intradialytic training in patients with end-stage renal disease: a systematic review and meta-analysis of randomized clinical trials assessing the effects of five different training interventions

OBJECTIVE

Patients with end-stage renal disease (ESRD) undergoing hemodialysis may have reduced dialysis adequacy (Kt/V), low cardiorespiratory fitness, and worse prognosis. Different types of intradialytic training (IDT) may serve as an adjunct therapy for the management of the ESRD. This systematic review and meta-analysis aimed to assess the impact of different types of IDT on clinical outcomes and functional parameters in ESRD.

METHODS

PubMed, Embase, CINAHL, Cochrane CENTRAL, Scopus, SPORTDiscus, and Google Scholar were searched for randomized clinical trials in adult patients with ESRD which compared IDT with usual care (UC), without language restrictions and published up to July 2019; a handsearch of references was also performed. Certainty of evidence was assessed using GRADE, and risk of bias in primary studies with the RoB 1.0 tool.

RESULTS

Fifty studies were included (n = 1757). Compared to UC, aerobic IDT improved Kt/V (WMD = 0.08), VO₂peak (WMD = 2.07 mL/kg/min), 6-minute walk test (6MWT) distance (64.98 m), reduced systolic blood pressure (- 10.07 mmHg) and C-reactive protein (- 3.28 mg/L). Resistance training increased 6MWT distance (68.50 m). Combined training increased VO₂peak (5.41 mL/kg/min) and reduced diastolic blood pressure (- 5.76 mmHg). Functional electrostimulation (FES) and inspiratory muscle training (IMT) improved 6MWT distance (54.14 m and 117.62 m, respectively). There was no impact on total cholesterol, interleukin-6, or hemoglobin levels. There was no difference in incidence of adverse events between the IDT and control groups. The certainty of evidence was variable according to the GRADE scale, with most outcomes rated very low certainty. The risk of bias assessment of primary studies showed unclear risk in most.

CONCLUSIONS

Aerobic, resistance, and combined training during hemodialysis, as well as FES and IMT, demonstrated to be effective for the treatment of the patient with ESRD. Our data should be interpreted in light of the unclear risk of bias of most evaluated articles and the low to very low certainty of evidence for evaluated outcomes.

PROSPERO REGISTRATION ID

CRD42017081338. DATA SHARING REPOSITORY: https://osf.io/fpj54/.

Cardiac stunning during haemodialysis: the therapeutic effect of intra-dialytic exercise

Background

Cardiovascular risk is elevated in end-stage renal disease. Left ventricular (LV) dysfunction is linked to repetitive transient ischaemia occurring during haemodialysis (HD). Cardiomyocyte ischaemia results in ‘cardiac stunning’, evidenced by regional wall motion abnormalities (RWMAs). Ischaemic RWMA have been documented during HD resulting in maladaptive cardiac remodelling and increased risk of heart failure. Intra-dialytic exercise is well tolerated and can improve quality of life and functional capacity. It may also attenuate HD-induced cardiac stunning.

Methods

This exploratory study aimed to assess the effect of intra-dialytic cycle ergometry on cardiac stunning. Twenty exercise-naïve participants on maintenance HD (mean ± SD, 59 ± 11 years) underwent resting echocardiography and maximal cardiopulmonary exercise testing. Subsequently, cardiac stunning was assessed with myocardial strain-derived RWMAs at four time points during (i) standard HD and (ii) HD with 30 min of sub-maximal intra-dialytic cycle ergometry at a workload equivalent to 90% oxygen uptake at the anaerobic threshold (VO₂AT). Central haemodynamics and cardiac troponin I were also assessed.

Results

Compared with HD alone, HD with intra-dialytic exercise significantly reduced RWMAs after 2.5 h of HD (total 110 ± 4, mean 7 ± 4 segments versus total 77 ± 3, mean 5 ± 3, respectively; P = 0.008). Global cardiac function, intra-dialytic haemodynamics and LV volumetric parameters were not significantly altered with exercise.

Conclusions

Intra-dialytic exercise reduced cardiac stunning. Thirty minutes of sub-maximal exercise at 90% VO₂AT was sufficient to elicit acute cardio-protection. These data potentially demonstrate a novel therapeutic effect of intra-dialytic exercise.

Effects of intradialytic cycling exercise on exercise capacity, quality of life, physical function and cardiovascular measures in adult haemodialysis patients: a systematic review and meta-analysis

Background

Intradialytic cycling (IDC), delivered during haemodialysis (HD), has the potential to improve many health issues. This systematic review and meta-analysis examine the evidence on the effects of IDC on exercise capacity, quality of life (QoL), physical function and cardiovascular health.

Methods

Twenty-four databases were searched alongside Internet and hand searching, and consultation with experts. Eligibility criteria were cluster randomized, randomized and quasi-randomized controlled trials (RCTs) of IDC versus usual care in prevalent adult HD patients. Primary outcome measures were exercise capacity (VO2 peak and field tests) and QoL. Secondary measures were cardiac and physical function.

Results

Thirteen RCTs were eligible. Eight provided data for use in meta-analyses, which indicated no significant change in VO2 peak (mean difference, MD 1.19 mL/kg/min, 95% confidence interval -1.15 to 3.52, P = 0.3), physical (mean change, MC 1.97, -8.27 to 12.22, P = 0.7) or mental component (MC 3.37, -7.94 to 14.68, P = 0.6) summary scores of the Medical Outcomes Short Form 36, pulse wave velocity (MD -0.57 m/s, -1.55 to 0.41, P = 0.4), systolic (MD -2.28 mmHg, -14.46 to 9.90, P = 0.7) or diastolic blood pressure (MD 2.25 mmHg, -3.01 to 7.50, P = 0.4) following IDC. IDC, however, leads to an improvement in performance on the 6-min walk test (MD 87.84 m, 39.60-136.09, P = 0.0004). All included studies were considered to have high risk of bias.

Conclusions

There is insufficient evidence demonstrating whether cycling exercise during HD improves patient outcomes. High-quality, adequately powered RCTs of IDC are required.

Attitudes of hemodialysis patients, medical and nursing staff towards patients' physical activity

PURPOSE

Patients with end-stage renal disease (ESRD) seem to have a negative attitude towards physical activity, which is mainly favored by the lack of counseling provided by the medical and nursing staff. The aim of this study was to investigate the attitudes of both ESRD patients and medical staff on the participation and promotion of physical activity and identify the obstacles that discourage patients' involvement in intervention programs.

STUDY DESIGN

Subjective assessment questionnaires and the International Physical Activity Questionnaire were administrated to hemodialysis patients and medical staff, to investigate the association between patient's barriers to physical activity, the total intensity level of physical activity, and attitudes of both ESRD patients and medical staff on the participation and promotion of physical activity.

RESULTS

A total of 103 ESRD patients (61 men, 59.2%), 20 nephrologists (12 men, 60.0%), and 72 nurses (61 women, 84.7%) participated in the study. Most commonly reported patient's barriers were fatigue on dialysis (97.4%) and non-dialysis days (55.1%). Healthcare staff showed positive attitude towards renal rehabilitation exercise programs. However, most of physicians (85.0%) and nurses (83.3%) did not have previous experience with interventional exercise rehabilitation programs. Binary logistic regression revealed significant association between patients' inactivity, demographic data, and barriers towards physical activity, such as fatigue and pain in dialysis and non-dialysis days (p < 0.05), family's and physician's concern (p < 0.05), too many medical problems (p < 0.05), the fear of getting hurt (p = 0.01), and unwillingness for exercise (p < 0.05). Interestingly, healthcare staff's negative attitudes toward patient's physical activity seem to be strongly associated with patient's inactivity status.

CONCLUSION

Healthcare staff negative attitudes and multiple related barriers especially fatigue on dialysis and non-dialysis days, towards ESRD patient's physical activity, suppress desire for exercise and active patients' status, leading them to abstain from it.

Are dialysis patients too frail to exercise?

Clinical manifestations of functional and morphological muscular abnormalities in dialysis patients are muscle weakness and low exercise capacity, possibly leading to a sedentary life style with low physical activity. Low cardiorespiratory fitness and muscle atrophy and weakness contribute to the development of frailty and affect patients' ability to physically navigate their environment. While many dialysis patients may appear too frail to participate in moderate-to-vigorous aerobic exercise training, those who can complete such programs appear to derive substantial benefit. Less vigorous aerobic exercise, resistance training, and alternative forms of exercise can also be beneficial. Most patients on dialysis are not too frail to perform resistance exercise of adequate intensity to achieve increases in muscle size and strength, therefore, frailty should not be considered a contraindication to exercise.

The Effect of Mechanically-Generated Vibrations on the Efficacy of Hemodialysis; Assessment of Patients' Safety: Preliminary Reports

Muscle activity during a hemodialysis procedure improves its efficacy. We have formulated a hypothesis that vibrations generated by a specially-designed dialysis chair can, the same as physical exercise, affect the filtering of various fluids between fluid spaces during the hemodialysis procedure. This prospective and interventional study included 21 dialyzed patients. During a single dialysis session, each patient used a prototype device with the working name “vibrating chair”. The chair’s drive used a low-power cage induction motor, which, along with the worm gear motor, was a part of the low-frequency (3.14 Hz) vibration-generating assembly with an amplitude of 4 mm. Tests and measurements were performed before and after the vibration dialysis. After a single hemodialysis session including five 3-min cycles of vibrations, an increase in Kt/V in relation to non-vibration Kt/V (1.53±0.26 vs. 1.62±0.23) was seen. Urea reduction ratio increased significantly (0.73±0.03 vs. 0.75±0.03). A significant increase in systolic blood pressure was observed between the first and the third measurement (146±18 vs. 156±24). The use of a chair generating low-frequency vibrations increased dialysis adequacy; furthermore, it seems an acceptable and safe alternative to intradialytic exercise.

Serum heart-type fatty acid-binding protein decreases and soluble isoform of suppression of tumorigenicity 2 increases significantly by long-term physical activity

The aim of this prospective study was to investigate the influence of long-term physical activity on biomarkers for myocyte ischemia (heart-type fatty acid-binding protein, H-FABP), matrix remodelling/vascular stress (soluble isoform of suppression of tumorigenicity 2, sST2) and inflammation (soluble urokinase-type plasminogen activator receptor, suPAR). In this prospective observational study 109 subjects were recruited, 98 completed the study. Subjects were asked to perform exercise within the calculated training pulse for 8 months. The performance gain was measured/quantified by bicycle stress tests at the beginning and end of the observation period. Twenty-seven subjects with a performance gain <2.9% were excluded. suPAR, H-FABP and sST2 were measured in serum at baseline and after 2, 4 and 8 months by ELISA. We found a significant decrease in H-FABP (1.86 (0.86) to 1.29 (0.98) ng/mL; p<0.01) and a significant increase in sST2 levels (6126 (2759) to 6919 (3720) pg/mL; p=0.045) during the observation period of 8 months while there was no remarkable change in suPAR levels. We interpret the activity-induced decrease in H-FABP as sign of lower subclinical myocardial ischemia and better perfusion, probably due to a more economic metabolization and electrolyte balance. The increase in sST2 might reflect physiological sports-induced vascular stress. As H-FABP and sST2 play an important role in the pathomechanism of ischemic cardiomyopathy (iCMP) further studies should investigate the influence of regular physical activity on these biomarkers in a population of patients with iCMP. TRIAL REGISTRATION NUMBER: NCT02097199.

Exercise during hemodialysis does not affect the phenotype or prothrombotic nature of microparticles but alters their proinflammatory function

Hemodialysis patients have dysfunctional immune systems, chronic inflammation and comorbidity-associated risks of cardiovascular disease (CVD) and infection. Microparticles are biologically active nanovesicles shed from activated endothelial cells, immune cells, and platelets; they are elevated in hemodialysis patients and are associated with chronic inflammation and predictive of CVD mortality in this group. Exercise is advocated in hemodialysis to improve cardiovascular health yet acute exercise induces an increase in circulating microparticles in healthy populations. Therefore, this study aimed to assess acute effect of intradialytic exercise (IDE) on microparticle number and phenotype, and their ability to induce endothelial cell reactive oxygen species (ROS) in vitro. Eleven patients were studied during a routine hemodialysis session and one where they exercised in a randomized cross-over design. Microparticle number increased during hemodialysis (2064-7071 microparticles/μL, P < 0.001) as did phosphatidylserine+ (P < 0.05), platelet-derived (P < 0.01) and percentage procoagulant neutrophil-derived microparticles (P < 0.05), but this was not affected by IDE. However, microparticles collected immediately and 60 min after IDE (but not later) induced greater ROS generation from cultured endothelial cells (P < 0.05), suggesting a transient proinflammatory event. In summary IDE does not further increase prothrombotic microparticle numbers that occurs during hemodialysis. However, given acute proinflammatory responses to exercise stimulate an adaptation toward a circulating anti-inflammatory environment, microparticle-induced transient increases of endothelial cell ROS in vitro with IDE may indicate the potential for a longer-term anti-inflammatory adaptive effect. These findings provide a crucial evidence base for future studies of microparticles responses to IDE in view of the exceptionally high risk of CVD in these patients.

Hemodynamic Instability during Dialysis: The Potential Role of Intradialytic Exercise

Acute haemodynamic instability is a natural consequence of disordered cardiovascular physiology during haemodialysis (HD). Prevalence of intradialytic hypotension (IDH) can be as high as 20–30%, contributing to subclinical, transient myocardial ischemia. In the long term, this results in progressive, maladaptive cardiac remodeling and impairment of left ventricular function. This is thought to be a major contributor to increased cardiovascular mortality in end stage renal disease (ESRD). Medical strategies to acutely attenuate haemodynamic instability during HD are suboptimal. Whilst a programme of intradialytic exercise training appears to facilitate numerous chronic adaptations, little is known of the acute physiological response to this type of exercise. In particular, the potential for intradialytic exercise to acutely stabilise cardiovascular hemodynamics, thus preventing IDH and myocardial ischemia, has not been explored. This narrative review aims to summarise the characteristics and causes of acute haemodynamic instability during HD, with an overview of current medical therapies to treat IDH. Moreover, we discuss the acute physiological response to intradialytic exercise with a view to determining the potential for this nonmedical intervention to stabilise cardiovascular haemodynamics during HD, improve coronary perfusion, and reduce cardiovascular morbidity and mortality in ESRD.

Intradialytic exercise training modalities on physical functioning and health-related quality of life in patients undergoing maintenance hemodialysis: systematic review and meta-analysis

OBJECTIVE

To determine the effects of different intradialytic exercise training modalities on physical functioning and health-related quality of life of maintenance hemodialysis patients.

METHODS

We searched MEDLINE, Cochrane Trials Register and CINAHL for controlled trials that evaluated the effects of intradialytic exercise training for maintenance hemodialysis patients and published from the earliest available date to December 2017. Weighted mean difference and 95% confidence interval (CI) were calculated, and heterogeneity was assessed using the I² test.

RESULTS

Fifty-six studies met the study criteria, comprising a total of 2586 patients. Compared with no exercise, combined aerobic and resistance exercise resulted in significant improvement in peak VO₂ weighted mean difference (5.1 mL kg^-1 min^-1; 95% CI: 3.4, 6.8 mL kg^-1 min^-1), depression symptoms (-7.32; 95% CI -9.31, -5.33) and both physical function (10.67 points; 95% CI 1.08, 20.25 points) and vitality (10.01 points; 95% CI 4.30, 15.72 points) domains of health-related quality of life. Resistance exercise alone was significantly associated with improvement in the 6-minute walk test distance (30.2 m; 95% CI 24.6, 35.9 m), knee extensor strength (0.6 N; 95% CI 0.1, 1.0 N) and Physical Component Score of health-related quality of life (9.53 points; 95% CI -3.09, 22.15 points) when compared with control group. Aerobic exercise alone was not significantly associated with aerobic capacity and quality of life improvement.

CONCLUSION

The results provide support to interventions that combine intradialytic aerobic and resistance exercises to improve physical functioning and quality of life in end-stage renal disease patients undergoing hemodialysis.

Comparison of Muscle Mass Indices Using Computed Tomography or Dual X-Ray Absorptiometry for Predicting Physical Performance in Hemodialysis Patients

BACKGROUND/AIMS

Our study aims to evaluate the association between thigh muscle cross-sectional area (TMA) using computed tomography (CT), or appendicular skeletal muscle mass (ASM) using dual energy X-ray absorptiometry (DEXA), and physical performance levels in hemodialysis (HD) patients.

METHODS

Patients were included if they were on HD for ≥6 months (n = 84). ASM and TMA were adjusted to body weight (BW, kg) or height2 (Ht2, m2). Each participant performed a short physical performance battery test (SPPB), a sit-to-stand for 30 second test (STS30), a 6-minute walk test (6-MWT), a timed up and go test (TUG), and hand grip strength (HGS) test.

RESULTS

Correlation coefficients for SPPB, GS, 5STS, STS30, 6-MWT, and TUG were highest in TMA/BW. Results from partial correlation or linear regression analyses displayed similar trends to those derived from Pearson's correlation analyses. An increase in TMA/BW or TMA/Ht2 was associated with a decreased odds ratio of low SPPB, GS, or HGS in multivariate analyses. Indices using DEXA were associated with a decreased odds ratio of a low HGS only in multivariate analysis.

CONCLUSION

TMA indices using CT may be more valuable in predicting physical performance or strength in HD patients.

The Effect of Intra-Dialytic Exercise on Inflammation and Blood Endotoxin Levels

Background: In healthy individuals, an acute inflammatory response occurs after intense exercise due to gut ischaemia and intestinal bacterial endotoxin translocation into the bloodstream. This process maybe exacerbated in patients who exercise during dialysis due to large volume shifts experienced by many during haemodialysis (HD). The acute effect of intra-dialytic exercise on blood endotoxins and inflammation is not known. Method: The effect of intra-dialytic exercise on blood endotoxin and inflammation was investigated in 10 patients and compared with resting haemodialysis. Blood was measured for endotoxin and inflammatory biomarkers before and after dialysis. Result: With the exception of one sample, all samples tested negative for endotoxin. Intra-dialytic exercise attenuated the rise of interleukin-6, tumour necrosis factor-α and high-sensitivity C-reactive protein after the HD procedure. Conclusion: Intra-dialytic exercise was not associated with an observable rise in blood endotoxin, although it may ameliorate the inflammatory effects of the HD procedure. Larger studies are needed to confirm this finding.

Intestinal Barrier Disturbances in Haemodialysis Patients: Mechanisms, Consequences, and Therapeutic Options

There is accumulating evidence that the intestinal barrier and the microbiota may play a role in the systemic inflammation present in HD patients. HD patients are subject to a number of unique factors, some related to the HD process and others simply to the uraemic milieu but with common characteristic that they can both alter the intestinal barrier and the microbiota. This review is intended to provide an overview of the current methods for measuring such changes in HD patients, the mechanisms behind these changes, and potential strategies that may mitigate these modifications. Lastly, intradialytic exercise is an increasingly employed intervention in HD patients; however the potential implications that this may have for the intestinal barrier are not known; therefore future research directions are also covered.

Comparison of Ambulatory Blood Pressure Patterns in Patients With Intradialytic Hypertension and Hemodialysis Controls

Background/Aims

Intradialytic hypertension (IH) patients have higher mortality risk than other hemodialysis patients and have been shown to have higher ambulatory blood pressure (BP). We hypothesized that interdialytic BP patterns would differ in IH patients and hypertensive hemodialysis controls.

Methods

We consecutively screened hemodialysis patients at our university-affliated units. Based on pre and post-HD BP measurements during the prior 2 week period, we identified IH patients and demographically matched hemodialysis controls. We measured ambulatory interdialytic BP, fow-mediated vasodilation, and intradialytic endothelin-1 (ET-1). Using linear mixed-models, we compared BP slopes during the following intervals: 1–24 hours post-dialysis, 25–44 hours post-dialysis, and 1–44 hours post-dialysis.

Results

There were 25 case subjects with IH and 24 controls. Systolic BP during hours 1–44, 1–24, and 25–44 were 143.1 (16.5), 138.0 (21.2), and 150.8 (22.3) mmHg in controls. For IH subjects, they were 155.4 (14.2), 152.7 (22.8), and 156.5 (20.8) mmHg (p=0.008, 0.02, 0.4). In controls, the slopes were +0.6, +0.6, and +0.4 mmHg/hr. In IH subjects, they were +0.1, −0.3, and +0.3 mmHg/hr. The IH 1–24 hour slope differed from the IH 25–44 hour slope (p=0.001) and the control 1–24 hour slope (p=0.002). The change in ET-1 from pre to post dialysis was 0.5 (1.5) pg/mL in controls and 1.0 (2.3) pg/mL in IH patients (p=0.4). In a univariate model, there was an association with screening BP and BP slope (p=0.002 for controls and p=0.1 for IH patients).

Conclusions

Interdialytic BP patterns differ in IH patients and hemodialysis controls. The elevated post dialysis blood pressure persists for many hours in IH patients contributing to the overall increased BP burden.