Current best evidence recommendations on measurement and interpretation of physical function in patients with chronic kidney disease

Preoperative assessment for vascular access: Vascular mapping and handgrip strength

BACKGROUND

Reliable vascular access (VA) is required for patients receiving chronic hemodialysis (HD) treatment. Vascular mapping using duplex doppler ultrasonography (DUS) can aid in planning VA construction. Greater handgrip strength (HGS) was found to be associated with more developed distal vessels both in chronic kidney disease (CKD) patients and healthy individuals, and patients with lower HGS had worse morphologic vessel characteristics and were, therefore, less likely to construct distal VA.

OBJECTIVES

This study aims to describe and analyze clinical, anthropometric, and laboratory characteristics of patients who underwent vascular mapping prior to VA creation.

RESEARCH DESIGN

Prospective analysis.

SUBJECTS

Adult patients with CKD referred for vascular mapping, at a tertiary center, between March 2021 and August 2021.

MEASURES

Preoperative DUS by a single experienced nephrologist was carried out. HGS was measured using a hand dynamometer, and PAD was defined as ABI < 0.9. Sub-groups were analyzed according to distal vasculature size (<2 mm).

RESULTS

A total of 80 patients were included, with a mean age of 65.7 ± 14.7 years; 67.5% were male, and 51.3% were on renal replacement therapy (RRT). Twelve (15%) participants had PAD. HGS was higher in the dominant arm (20.5 ± 12.0 vs 18.8 ± 11.2 kg). Fifty-eight (72.5%) patients had vessels smaller than 2 mm in diameter. There were no significant differences between groups concerning demographics or comorbidities (diabetes, HTN, PAD). HGS was significantly higher in patients with distal vasculature greater than or equal to 2 mm in diameter (dominant arm: 26.1 ± 15.5 vs 18.4 ± 9.7 kg, p = 0.010; non-dominant arm: 24.1 ± 15.3 vs 16.8 ± 8.6, p = 0.008).

CONCLUSIONS

Higher HGS was associated with more developed distal cephalic vein and radial artery. Low HGS might be an indirect sign of suboptimal vascular characteristics, which might help predict the outcomes of VA creation and maturation.

A Current State of the Art and Science of Exercise in Dialysis: A Narrative Review

Purpose of the review

The purpose of the review is to discuss current proven benefits and problems of integrating exercise in the care of people receiving dialysis by reviewing literature from the last few years and identifying important questions that still need to be asked and answered.

Methods

A focused review and appraisal of the literature were done. Original peer-reviewed articles, review articles, opinion pieces and guidelines were identified from PubMed and Google Scholar databases. Only sources in English were accessed. Search terms "exercise" and "dialysis" were used to find active recruiting randomized trials in various clinical trial registry platforms.

Key findings

Numerous studies have demonstrated the benefits of exercise training in individuals receiving dialysis, limited by factors such as short duration of follow-up and inconsistent adverse event reporting and outcomes selected. Notable gaps in exercise research in dialysis include ways to maintain programs and patient motivation, studies in peritoneal dialysis and home hemodialysis patients, and how best to define and measure outcomes of interest.

Implications

This review summarizes the current state of exercise in people receiving dialysis and serves as a call to action to conduct large, randomized controlled trials to improve the quality of evidence needed to implement and sustain innovative, exercise interventions, and programs for this population.

Effects of intradialytic inspiratory muscle training at different intensities on diaphragm thickness and functional capacity: clinical trial protocol in patients undergoing haemodialysis

INTRODUCTION

Patients with end-stage renal disease (ESRD) undergoing haemodialysis (HD) commonly present with a sedentary behaviour and reduced functional capacity, factors that can compromise their prognosis. Intradialytic inspiratory muscle training (IMT) can increase respiratory muscle strength and, consequently, improve functional capacity, besides being easy to apply, cheap and performed in a supervised setting. However, few studies show the effects of this type of training applied at different intensities in this population. This study aims to compare the effects of IMT at different intensities in adults with ESRD undergoing HD.

METHODS AND ANALYSIS

A randomised, double-blind, sham-controlled trial will be conducted on 36 subjects randomly allocated into three groups: IMT at intensities of 30% or 50% of maximal inspiratory pressure (intervention groups), or 10% of maximal inspiratory pressure (sham-IMT). All the interventions will be supervised and performed three times per week, for 12 weeks, totalling 36 sessions. The primary outcomes are the 6-minute walk test, diaphragm thickness and the response of VO₂peak post-intervention. Respiratory muscle strength, 24-hour ambulatory blood pressure measurement and the Kidney Disease Quality of Life 36-item short form survey will be evaluated as secondary outcomes.

ETHICS AND DISSEMINATION

This study has been approved by the Research Ethics Committee of the Hospital de Clínicas de Porto Alegre (ID: 2020-0458). The results of this study will be disseminated by conference presentations and peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04660383.

Effects of a Combined Intradialytic Exercise Training Program and Music on Cardiac Autonomic Nervous System Activity in Hemodialysis Patients

This study aimed to examine the effect of an intradialytic exercise program in combination with music on heart rate variability (HRV) indices and functional capacity in patients on maintenance hemodialysis (HD). Methods: Forty HD patients were randomized to four training groups for six months: the combined music and exercise group (Group A), the exercise group (Group B), the music group (Group C), and the control group (Group D). At baseline and after 6 months, all participants underwent both short- (for 30 min) and long- (for 24 h) term measurements of HRV and functional capacity assessment with a 6 min walking test (6MWT). Patients of groups A and C listened to preferred music. Results: Long-term HRV analysis showed that standard deviation of all normal-to-normal RR intervals (SDNN) and the square root of the mean squared differences of successive RR intervals (rMSSD) were significantly higher at the end of the study in groups A (by 13.2% and 47.3%), B (by 15.1% and 50%), and C (by 9.0% and 30.1%), compared to group D (p < 0.05). Values of rMSSD and percentage of RR intervals differing by more than 50 ms from the preceding RR interval (pNN50) were elevated in groups A (by 35.6% and 142.9%), B (by 36.1% and 75%), and C (by 15.2% and 28.6%), compared to baseline measurements (p < 0.05). Also, pNN50 was increased in group A compared to groups B (by 21.4%), C (by 88.9%), and D (by 142.9%) (p < 0.05). Similar results were noted by short-term HRV analysis. Functional capacity was improved at the end of the 6-month study in groups A (by 20.3% and 25.7%) and B (by 15.8% and 21.1%) compared to groups C and D (p < 0.05). Conclusions: Intradialytic exercise combined with music-listening can improve the functional capacity and cardiac autonomic nervous system activity in hemodialysis patients.

Age, diabetes mellitus, and dialysis modality are associated with risk of poor muscle strength and physical function in hemodialysis and peritoneal dialysis patients

Background

Due to the poor outcomes associated with the impairment of physical function and muscle strength in patients on maintenance dialysis, it is important to understand the factors that may influence physical function and muscle strength. The aim of this study was to explore the factors associated with physical function in hemodialysis and peritoneal dialysis patients.

Methods

Patients with chronic kidney disease on dialysis for at least 3 months, aged 18 years old or above, were enrolled. Physical function was assessed by handgrip strength, gait and sit-to-stand tests, and the Short Physical Performance Battery (SPPB). Clinical and laboratory data were collected to verify the association with physical function parameters through binary logistic regression.

Results

One-hundred ninety patients on maintenance dialysis were included; 140 patients (73.7%) on hemodialysis and 50 (26.3%) on peritoneal dialysis. The mean age was 57.3 ± 14.9 years, 109 (57.4%) were male, and 87 (45.8%) were older than 60 years. The median SPPB was 8.0 points (6.0–10.0 points) and the mean ± standard deviation of handgrip strength was 24.7 ± 12.2 kg. Binary logistic regression showed that age, type of renal replacement therapy, diabetes mellitus, and serum creatinine were significantly associated with both higher 4-meter gait test times and lower SPPB scores. Only age and diabetes mellitus were associated with higher sit-to-stand test times, while age and ferritin were associated with lower handgrip strength.

Conclusion

Age, diabetes mellitus, serum creatinine, and hemodialysis modality are factors related to physical function in dialysis patients.

Physical Function and Clinical Outcomes in Hemodialysis Patients: China Dialysis Outcomes and Practice Patterns Study

Background

Hemodialysis (HD) patients usually have impaired physical function compared with the general population. Self-reported physical function is a simple method to implement in daily dialysis care. This study aimed to examine the association of self-reported physical function with clinical outcomes of HD patients.

Methods

The Dialysis Outcomes and Practice Patterns Study (DOPPS) is a prospective cohort study. Data on 1,427 HD patients in China DOPPS5 were analyzed. Self-reported physical function was characterized by 2 items of "moderate activities limited level" and "climbing stairs limited level." Demographic data, comorbidities, hospitalization, and death records were collected from patients' records. Associations between physical function and outcomes were analyzed using COX regression models.

Results

Compared to "limited a lot" in moderate activities, "limited a little" and "not limited at all" groups were associated with lower all-cause mortality after adjusted for covariates (HR: 0.652, 95% CI: 0.435-0.977, and HR: 0.472, 95% CI: 0.241-0.927, respectively). And, not limited in moderate activities was associated with lower risk of hospitalization than the "limited a lot" group after adjusted for covariates (HR: 0.747, 95% CI: 0.570-0.978). Meanwhile, compared to "limited a lot" in climbing stairs, "limited a little" and "not limited at all" groups were associated with lower all-cause mortality (HR: 0.574, 95% CI: 0.380-0.865 and HR: 0.472, 95% CI: 0.293-0.762, respectively) but not hospitalization after fully adjusted.

Conclusion

Higher limited levels in self-reported physical function were associated with higher risk of all-cause mortality and hospitalization in HD patients.

Assessing physical activity and function in patients with chronic kidney disease: a narrative review

Physical activity potentially improves health outcomes in patients with chronic kidney disease (CKD) and recipients of kidney transplants. Although studies have demonstrated the beneficial effects of physical activity and exercise for primary and secondary prevention of non-communicable diseases, evidence for kidney patients is limited. To enlarge this evidence, valid assessment of physical activity and exercise is essential. Furthermore, CKD is associated with a decline in physical function, which may result in severe disabilities and dependencies. Assessment of physical function may help clinicians to monitor disease progression and frailty in patients receiving dialysis. The attention on physical function and physical activity has grown and new devices have been developed and (commercially) launched on the market. Therefore the aims of this review were to summarize different measures of physical function and physical activity, provide an update on measurement instruments and discuss options for easy-to-use measurement instruments for day-to-day use by CKD patients. This review demonstrates that large variation exists in the different strategies to assess physical function and activity in clinical practice and research settings. To choose the best available method, accuracy, content, preferable outcome, necessary expertise, resources and time are important issues to consider.

Effects of 12 months of detraining on health-related quality of life in patients receiving hemodialysis therapy

PURPOSE

Limited data exist regarding the effects of detraining on functional capacity and quality of life (QoL) in the hemodialysis population. The aim of the current study was to assess whether the discontinuation from a systematic intradialytic exercise training program will affect aspects of health-related QoL and functional capacity in hemodialysis patients.

METHODS

Seventeen hemodialysis patients (12 Males/5 Females, age 60.8 ± 13.6 year) participated in this study. Patients were assessed for functional capacity using various functional capacity tests while QoL, daily sleepiness, sleep quality, depression and fatigue were assessed using validated questionnaires at the end of a 12-month aerobic exercise program and after 12 months of detraining.

RESULTS

The detraining significantly reduced patients' QoL score by 20% (P = 0.01). More affected were aspects related to the physical component summary of the QoL (P < 0.001) rather than those related to the mental one (P = 0.096). In addition, the performance in the functional capacity tests was reduced (P < 0.05), while sleep quality (P = 0.020) and daily sleepiness scores (P = 0.006) were significantly worse after the detraining period. Depressive symptoms (P = 0.214) and the level of fatigue (P = 0.163) did not change significantly.

CONCLUSIONS

Detraining has a detrimental effect in patients' QoL, functional capacity and sleep quality. The affected physical health contributed significantly to the lower QoL score. It is crucial for the chronic disease patients, even during emergencies such as lockdowns and restrictions in activities to maintain a minimum level of activity to preserve some of the acquired benefits and maintain their health status.

Effects of Exercise Training Combined with Virtual Reality in Functionality and Health-Related Quality of Life of Patients on Hemodialysis

Objective: The progression of chronic kidney disease can directly affect patient's health-related quality of life (HRQoL). Exercise training is a good option to reverse the impacts caused by the disease. To escape from the monotonous routine and stimulate further practice, the therapist should consider making physical activity more playful. Using videogames during exercise training is possible to rehabilitate the patient aiming for fun beyond the organic condition. The present study aimed to evaluate the effects of exercise training combined with Virtual Reality (VR) in functionality and HRQoL of patients on hemodialysis. Materials and Methods: A randomized controlled study in which control group (n = 20) maintained only hemodialysis without any physical effort or intervention from the researchers and intervention group (n = 20) who performed endurance and strength physical exercises in combination with VR during hemodialysis for 12 weeks. All eligible patients underwent a familiarization of games and were evaluated by an investigator-blind for functional capacity, quality of life, and depressive symptoms. Functional capacity tests included walking speed, timed up and go (TUG), and Duke Activity Status Index (DASI). To evaluate a HRQoL, Kidney Disease and Quality-of-Life Short-Form (KDQOL-SF™, v. 1.3) was used and to investigate depressive symptoms, the Center for Epidemiological Scale-Depression. Paired sample t-tests were conducted to determine differences within each group. Repeated-measures analysis of variance (group vs. time) was used to assess group differences in our major outcomes. The level of significance was 5%. Results: The exercise improved functional capacity (TUG: P = 0.002, DASI: P < 0.001) and HRQoL in physical and specific domains: physical functioning (P = 0.047), role physical (P = 0.021), as well as in physical composite summary (P < 0.001) and effects of kidney disease (P = 0.013). There was no influence on depressive symptoms (P = 0.154). Conclusion: Physical training combined with VR improved functional capacity and some quality-of-life domains of hemodialysis patients.

Modifiable Physical Factors Associated With Physical Functioning for Patients Receiving Dialysis: A Systematic Review

Background: Patients receiving dialysis have reduced physical function, which is associated with unfavorable clinical outcomes and decreased quality of life. The authors aimed to identify and explore modifiable physical factors associated with physical function for patients receiving dialysis. Methods: Searches were performed in MEDLINE, Embase, Ovid Emcare, and The Cochrane Library in October 2018. Etiological studies involving dialysis populations that report association or predictive statistics between a modifiable physical factor and physical function were eligible for inclusion. Predictor variables were (1) modifiable via exercise and (2) considered an impairment in the International Classification of Functioning, Disability and Health. Results: Of 5384 titles screened, 23 studies were included. Thirteen studies focused on physical activity levels and muscle strength and the relationship with physical function while 2 studies investigated sedentary behavior. Twenty-one studies focused on hemodialysis populations. Studies related to physical activity levels displayed a moderately strong relationship with physical function, whereas muscle strength displayed a predominantly weak to moderate relationship. Conclusions: Physical activity levels, sedentary behavior levels, and muscle strength are related to physical function status for patients receiving dialysis. There is a need for robust longitudinal data to confirm the results of this investigation and for more focus on populations receiving peritoneal dialysis.

The relative importance of frailty, physical and cardiovascular function as exercise-modifiable predictors of falls in haemodialysis patients: a prospective cohort study

Background

Stage 5 chronic kidney disease (CKD-5) patients on haemodialysis (HD) are at high risk of accidental falls. Previous research has shown that frailty is one of the primary contributors to the increased risk of falling in this clinical population. However, HD patients often present with abnormalities of cardiovascular function such as baroreflex impairment and orthostatic dysregulation of blood pressure (BP) which may also be implicated in the aetiology of falling. Therefore, we aimed to explore the relative importance of frailty and cardiovascular function as potential exercise-modifiable predictors of falls in these patients.

Methods

Ninety-three prevalent CKD-5 patients on HD from three Renal Units were recruited for this prospective cohort study, which was conducted between October 2015 and August 2018. At baseline, frailty status was assessed using the Fried’s frailty phenotype, while physical function was evaluated through timed up and go (TUG), five repetitions chair sit-to-stand (CSTS-5), objectively measured physical activity, and maximal voluntary isometric strength. Baroreflex and haemodynamic function at rest and in response to a 60° head-up tilt test (HUT-60°) were also assessed by means of the Task Force Monitor. The number of falls experienced was recorded once a month during 12 months of follow-up.

Results

In univariate negative binomial regression analysis, frailty (RR: 4.10, 95%CI: 1.60–10.51, p = 0.003) and other physical function determinants were associated with a higher number of falls. In multivariate analysis however, only worse baroreflex function (RR: 0.96, 95%CI: 0.94–0.99, p = 0.004), and orthostatic decrements of BP to HUT-60° (RR: 0.93, 95%CI: 0.87–0.99, p = 0.033) remained significantly associated with a greater number of falls. Eighty falls were recorded during the study period and the majority of them (41.3%) were precipitated by dizziness symptoms, as reported by participants.

Conclusions

This prospective study indicates that cardiovascular mechanisms implicated in the short-term regulation of BP showed a greater relative importance than frailty in predicting falls in CKD-5 patients on HD. A high number of falls appeared to be mediated by a degree of cardiovascular dysregulation, as evidenced by the predominance of self-reported dizziness symptoms.

Trial registration

ClinicalTrials.gov (trial registration ID: NCT02392299; date of registration: March 18, 2015).

Physical performance, plasma S-klotho, and all-cause mortality in elderly dialysis patients: A prospective cohort study

The secreted protein form of the α-klotho gene, S-klotho, is gaining popularity as a predictor of overall morbimortality, and its role in dialysis patients has been recently highlighted. However, physical performance -which can be assessed through practical field-tests- might be a more practical prognostic marker. The present study aimed to analyze the relationship between physical performance, plasma S-klotho and all-cause mortality in this population. 30 male hemodialysis patients (71 ± 9 years) participated in this prospective, cohort study. Their plasma S-klotho levels and physical performance (assessed by means of the 6-minute walk test [6MWT], handgrip strength, and the sit-to-stand test [STS]) were determined at baseline, and the incidence of mortality was assessed 18-month later. Lower S-klotho levels were associated with a worse performance in all physical tests (all p < 0.05). 12 participants died during the 18 months following baseline measurements. An increased mortality risk was observed in those patients with a worse performance in the STS (RR: 3.0 [95%CI: 1.01-8.95], p < 0.05), the handgrip test (RR: 3.0 [95%CI: 1.01-8.95], p < 0.05) and the 6MWT (RR: 5.0 [95%CI: 1.31-19.07], p < 0.01), being the latter the best predictor of mortality. By contrast, this relationship was not found for plasma S-klotho (RR: 1.6 [95%CI: 0.65-1.35], p > 0.05). In summary, low plasma S-klotho levels are related to impaired physical performance in male dialysis patients. However, physical performance appears as a better and more practical predictor of mortality in this patient population.

Exercise interventions for improving objective physical function in patients with end-stage kidney disease on dialysis: a systematic review and meta-analysis

Patients with end-stage kidney disease on dialysis have increased mortality and reduced physical activity, contributing to impaired physical function. Although exercise programs have demonstrated a positive effect on physiological outcomes such as cardiovascular function and strength, there is a reduced focus on physical function. The aim of this review was to determine whether exercise programs improve objective measures of physical function indicative of activities of daily living for patients with end-stage kidney disease on dialysis. A systematic search of Medline, Embase, the Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature identified 27 randomized control trials. Only randomized control trials using an exercise intervention or significant muscular activation in the intervention, a usual care, nonexercising control group, and at least one objective measure of physical function were included. Participants were ≥18 yr of age, with end-stage kidney disease, undergoing hemo- or peritoneal dialysis. Systematic review of the literature and quality assessment of the included studies used the Cochrane Collaboration’s tool for assessing risk bias. A meta-analysis was completed for the 6-min walk test. Data from 27 studies with 1,156 participants showed that exercise, regardless of modality, generally increased 6-min walk test distance, sit-to-stand time or repetitions, and grip strength as well as step and stair climb times or repetitions, dynamic mobility, and short physical performance battery scores. From the evidence available, exercise, regardless of modality, improved objective measures of physical function for end-stage kidney disease patients undergoing dialysis. It is acknowledged that further well-designed randomized control trials are required.

Acute effect of photobiomodulation therapy on handgrip strength of chronic kidney disease patients during hemodialysis

Pre-exercise photobiomodulation therapy (PBMT) reduces fatigue and enhances performance in different populations. However, PBMT benefits have never been tested on chronic kidney disease (CKD) patients, who present muscle weakness, fatigue, and reduced functional performance. The objective of this study was to evaluate the acute effect of three different doses of the PBMT on maximal handgrip strength of CKD patients. Fifteen volunteers (58 ± 8 years, 10 male/5 female) under chronic hemodialysis treatment (6 ± 4 years) participated in a randomized, crossover, double-blind, placebo-controlled trial. Each patient was assessed at four hemodialysis sessions with 1 week interval between evaluations. Placebo or PBMT (cluster probe with five 850 nm/200 mW laser diodes) were applied at three sites along the flexors of the finger (total doses of 60, 90, or 120 J per arm). The maximal handgrip strength was evaluated before and after PBMT/placebo treatment in each session. Repeated measures ANOVA and intraclass correlation coefficients (ICC) confirmed no learning effect on handgrip tests, and high scores for test-retest reliability (ICC scores = 0.89 to 0.95). Significant strength increases occurred after PBMT application with doses of 60 J/arm (4.85%, p = 0.005, ES = 0.32) and 90 J/arm (4.45%, p = 0.013, ES = 0.25), while no changes were detected with placebo or 120 J/arm. In conclusion, in consensus with a recent systematic review, a single bout of the 60 J/arm was the best dose/response for increased strength of the small muscles (handgrip strength). In view of the increasing implementation of exercise programs during hemodialysis, the current study opens a new field for PBMT for CKD patients.

Intradialytic Exercise: One Size Doesn't Fit All

Purpose: Hemodialysis patients commonly have impaired physical performance and mental health. We studied the effects of an intradialytic exercise program on these variables.

Methods: 27 patients (33% women; 68 ± 13 years) were enrolled in a 14-week intradialytic endurance-resistance training program (‘exercise’ group, 40 programmed sessions per patient); 40 hemodialysis patients (28% women; 68 ± 11 years) performing no exercise during the same time length were used as controls. Endpoints included physical performance (6-min walk test [6MWT], 10-repetition sit to stand [STS-10] and handgrip strength), emotional status (Beck’s depression inventory and State-Trait Anxiety Inventory), and mental and physical component scores of the short-from (SF)-12 Health Survey.

Results: There were no differences (p> 0.05) between groups at baseline for sex distribution, or mean age, body mass index and time spent on dialysis. Exercise benefits were observed for 6MWT (11 and −3% for the exercise and control groups, respectively; p < 0.001), STS-10 performance time (-22 and 6%; p < 0.001) and handgrip strength (4 and −4%; p < 0.02). No significant benefits (p> 0.05) were observed for emotional status endpoints or SF-12 component scores. Despite significant benefits on physical performance, the proportion of clinically meaningful responders was low (<50%). Responsiveness was dependent on baseline physical performance (p < 0.05) but not on age or sex (p > 0.05).

Conclusion: A 14-week intradialytic training program induced significant improvements on physical performance. However, the rate of clinically meaningful responders observed in the present study was low, being the level of responsiveness dependent on baseline physical status. Efforts to individualize exercise prescription are needed in clinical practice.

Physical Therapy Considerations for Chronic Kidney Disease and Secondary Sarcopenia

Chronic kidney disease (CKD) is a progressive condition that may negatively affect musculoskeletal health. These comorbidities may include malnutrition, osteoporosis, and decreased lean body mass. Secondary sarcopenia due to CKD may be associated with mobility limitations and elevated fall risk. Physical therapists are well-positioned among the health care team to screen for secondary sarcopenia in those with CKD and for the treatment of musculoskeletal comorbid conditions that may affect functional performance. Given the consequences of both low muscle mass and low bone mineral density, appropriate and timely physical therapy is important for fall risk assessment and intervention to minimize the susceptibility to bone fracture. While strength training has been studied less frequently than aerobic training for the management of secondary CKD conditions, evidence suggests that this patient population benefits from participation in strength training programs. However, the provision of a formal exercise prescription by a health care professional, along with formal implementation of an exercise program, may need to be more fully integrated into the standard plan of care for individuals with CKD.

Integrative Examination of Motor Abilities in Dialysis Patients and Selection of Tests for a Standardized Physical Function Assessment

To reduce the need for a large number of executed physical function tests we examined inter-relations and determined predictive power for daily physical activity of the following tests: 6-min walk, 10 repetition sit-to-stand, time up-and-go, Storke balance, handgrip strength, upper limb tapping and sitting forward bend tests. In 90 dialysis and 140 healthy control subjects we found high correlations between all tests, especially those engaging lower extremities. Sit-to-stand, forward bend and handgrip strength were selected for the test battery and composite motor performance score. Sit-to-stand test was superior in terms of sensitivity to uremia effects and association with daily physical function in adjusted analyses. There was no incremental value in calculating the composite performance score. We propose to standardize the physical function assessment of dialysis patients for cross-sectional and longitudinal observations with three simple, cheap, well-accessible and easily performed test tools: sit-to-stand test, handgrip strength and Human Activity Profile questionnaire.

Efficacy of blood flow restriction exercise during dialysis for end stage kidney disease patients: protocol of a randomised controlled trial

BACKGROUND

Exercise during haemodialysis improves strength and physical function. However, both patients and clinicians are time poor, and current exercise recommendations add an excessive time burden making exercise a rare addition to standard care. Hypothetically, blood flow restriction exercise performed during haemodialysis can provide greater value for time spent exercising, reducing this time burden while producing similar or greater outcomes. This study will explore the efficacy of blood flow restriction exercise for enhancing strength and physical function among haemodialysis patients.

METHODS

This is a randomised controlled trial design. A total of 75 participants will be recruited from haemodialysis clinics. Participants will be allocated to a blood flow restriction cycling group, traditional cycling group or usual care control group. Both exercising groups will complete 3 months of cycling exercise, performed intradialytically, three times per week. The blood flow restriction cycling group will complete two 10-min cycling bouts separated by a 20-min rest at a subjective effort of 15 on a 6 to 20 rating scale. This will be done with pressurised cuffs fitted proximally on the active limbs during exercise at 50% of a pre-determined limb occlusion pressure. The traditional cycling group will perform a continuous 20-min bout of exercise at a subjective effort of 12 on the same subjective effort scale. These workloads and volumes are equivalent and allow for comparison of a common blood flow restriction aerobic exercise prescription and a traditional aerobic exercise prescription. The primary outcome measures are lower limb strength, assessed by a three repetition maximum leg extension test, as well as objective measures of physical function: six-minute walk test, 30-s sit to stand, and timed up and go. Secondary outcome measures include thigh muscle cross sectional area, body composition, routine pathology, quality of life, and physical activity engagement.

DISCUSSION

This study will determine the efficacy of blood flow restriction exercise among dialysis patients for improving key physiological outcomes that impact independence and quality of life, with reduced burden on patients. This may have broader implications for other clinical populations with similarly declining muscle health and physical function, and those contraindicated to higher intensities of exercise.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Register: ACTRN12616000121460.

Exercise and CKD: Skeletal Muscle Dysfunction and Practical Application of Exercise to Prevent and Treat Physical Impairments in CKD

Patients with chronic kidney disease experience substantial loss of muscle mass, weakness, and poor physical performance. As kidney disease progresses, skeletal muscle dysfunction forms a common pathway for mobility limitation, loss of functional independence, and vulnerability to disease complications. Screening for those at high risk for mobility disability by self-reported and objective measures of function is an essential first step in developing an interdisciplinary approach to treatment that includes rehabilitative therapies and counseling on physical activity. Exercise has beneficial effects on systemic inflammation, muscle, and physical performance in chronic kidney disease. Kidney health providers need to identify patient and care delivery barriers to exercise in order to effectively counsel patients on physical activity. A thorough medical evaluation and assessment of baseline function using self-reported and objective function assessment is essential to guide an effective individualized exercise prescription to prevent function decline in persons with kidney disease. This review focuses on the impact of kidney disease on skeletal muscle dysfunction in the context of the disablement process and reviews screening and treatment strategies that kidney health professionals can use in clinical practice to prevent functional decline and disability.

Association of Albuminuria and Estimated Glomerular Filtration Rate with Functional Performance Measures in Older Adults with Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is increasingly common and disproportionately affects older adults. The contribution of kidney disease to the functional impairment noted in the elderly CKD population is unclear.

METHODS

This is a cross-sectional analysis of a hypertensive cohort of people aged ≥75 years from the Systolic Blood Pressure Intervention Trial. We evaluated estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) as predictors of 3 measures of functional status: EuroQol-5 Dimensional (EQ-5D) score, Falls Efficacy Scale (FES) score, and gait speed. Linear regression models were used to evaluate the associations between our independent variables and outcome measures.

RESULTS

Our analysis included 2,620 participants, mean age of 79.9 (4.0) years. Unadjusted models showed that lower eGFR level and higher UACR level were associated with lower EQ-5D (p < 0.001 for both) and slower gait speed (p < 0.001 for both) and worse scores on FES (p = 0.032 and p = 0.039). In the fully adjusted models, higher levels of UACR remained significantly associated with lower EQ-5D scores and slower gait speed (p = 0.011 and p = 0.002, respectively). In contrast, level of eGFR was not associated with any functional outcome measures when accounting for covariates.

CONCLUSIONS

In individuals aged ≥75 years, albuminuria and eGFR were associated with impairments in physical performance and self-reported functional status; however, only the association with albuminuria remained after adjusting for relevant demographics and comorbidities. Evaluation of albuminuria may provide an additional tool for identifying older individuals at risk for functional impairment.

Six-Minute Walk Test in Renal Failure Patients: Representative Results, Performance Analysis and Perceived Dyspnea Predictors

Objectives

Six-minute walk test in dialysis population hasn’t been consistently evaluated for the isolated impact of renal failure and other predictive factors. We measured six-minute walk distance in patients representative for low level of comorbidity and searched for potentially modifiable predictive factors of performance and dyspnea.

Methods

This was a cross-sectional study with hemodialysis patients (N = 90) and control subjects (N = 140). Main outcome measures: six-minute walk test distance and dyspnea severity using the 10-item Borg scale.

Results

Median distance decreased from 600m below the 6^th decade to 420m in the 8^th decade of age. Dialysis dependence predicted 101.5m shorter distance in the adjusted model that explained 70% of variability in results. Adjusted for significant covariates of age, height and spontaneous gait speed, fat mass (but not lean body mass) and serum total iron binding capacity were significantly associated with distance (95% CI for B coefficients -4.6 to –1.4 m/kg and 0.1 to 5 m/μmol/l, respectively). Serum total iron binding capacity as an explanatory variable was superior to C-reactive protein and albumin. Dialysis dependence, odds ratio (OR) 2.97 (1.11–7.94), spontaneous gait speed, OR 0.08 (0.02–0.41), rate-pressure product, OR 1.15 (1.08–1.23) and hemoglobin, OR 0.95 (0.92–0.98) predicted dyspnea in the adjusted model.

Conclusions

Renal failure without the confounding effect of comorbidity is a significant negative predictor of performance at six-minute walk test and perceived level of dyspnea. Body fat mass and serum total iron binding capacity are the main potentially modifiable predictors of performance, total iron binding capacity being superior to C-reactive protein and albumin. Although hemoglobin is not associated with test performance, it negatively predicts perceived shortness of breath.

Isolated Effects of Renal Failure, Anthropometric Indices, and Serum Total Iron-Binding Capacity as Determinants of Muscle Performance in Hemodialysis Patients

OBJECTIVE

We quantified the isolated impact of end-stage renal disease (ESRD) on physical performance under contemporary hemodialysis treatment independent of comorbid diseases, characterized principal anthropometric components, and adjusted for their influence and compared associations of C-reactive protein (CRP), albumin, and serum total iron-binding capacity (TIBC) with muscle function.

DESIGN

A case-control cross-sectional study.

SETTING

University medical hospital and outpatient hemodialysis units.

SUBJECTS

Ninety prevalent hemodialysis patients without important comorbidities and 140 controls.

MAIN OUTCOME MEASURES

Handgrip strength (HGS) and 10-repetition sit-to-stand time (STS-10).

RESULTS

Principal component analysis revealed 3 representative anthropometric measures to be included in explanatory models of muscle performance additional to body height: lean body mass, fat mass, and joint size. Controlling for these covariates, age, sex, and residual comorbidity, ESRD was associated with a modest 7.5% reduction in HGS (B = -2.57 kg; 95% confidence interval: -4.81 to -0.39; P = .005; model R(2) 0.74) and a relatively larger prolongation of 27% in STS-10 time (B = 4s; 95% confidence interval: 2.61 to 5.4; P < .001; model R(2) 0.53). Lean body mass and height significantly predicted both tests, fat mass, and wrist size predicted HGS. In the subgroup of dialysis patients, only TIBC showed a significant association with HGS independently from age, sex, wrist size, whereas CRP and albumin did not. STS-10 time was not associated with any of these biomarkers. Results remained stable in sensitivity analyses excluding patients with reported chronic regional motor difficulties and aches.

CONCLUSIONS

ESRD with contemporary hemodialysis therapy has a relatively modest negative comorbidity-free association with HGS and a larger effect on STS-10 lower extremity performance. Nonmodifiable anthropometric indices (body height and for HGS wrist size) have a significant independent impact and should be consistently adjusted for in future studies. In low-comorbidity dialysis patients, TIBC is a superior predictor of HGS compared with albumin and CRP.

Influence of Chronic Kidney Disease on Physical Function and Quality of Life in Patients after Coronary Artery Bypass Grafting

AIMS

The purposes of this study were (1) to compare body composition, physical function, and quality of life (QOL) between patients after coronary artery bypass grafting (CABG) with and without chronic kidney disease (CKD) and (2) to analyze the factors associated with physical function and QOL domains in these patients.

METHODS

Thirty male post-CABG patients with CKD and 30 matched controls were recruited. All subjects underwent dual-energy X-ray absorptiometry for body composition evaluation. Physical function tests included the grip strength test, 30-second chair stand test (30CST), and 6-min walk test (6MWT). Physical activity and QOL were assessed using the long form of the International Physical Activity Questionnaire and the World Health Organization Quality of Life Instrument (WHOQOL)-BREF, respectively.

RESULTS

Post-CABG patients with CKD exhibited a lower arm lean mass and higher percent leg fat mass than those without CKD (p < 0.05). The patients with CKD also had lower 30CST scores, 6MWT distances, and QOL domain of social relationships scores than those without CKD after adjusting for covariates (p < 0.05). If NYHA class was considered in the model, NYHA class became the most important factor associated with 6MWT distances (β = -0.647, p < 0.001) and the QOL domains of psychological health (β = -0.285, p = 0.027) and environment (β = -0.406, p = 0.001).

CONCLUSION

Post-CABG patients with CKD had worse body composition, physical function, and QOL than those without CKD, and this might be associated with a worse NYHA class.

Beneficial effects of an intradialytic cycling training program in patients with end-stage kidney disease

In chronic kidney disease (CKD), oxidative stress (OS) plays a central role in the development of cardiovascular diseases. This pilot program aimed to determine whether an intradialytic aerobic cycling training protocol, by increasing physical fitness, could reduce OS and improve other CKD-related disorders such as altered body composition and lipid profile. Eighteen hemodialysis patients were randomly assigned to either an intradialytic training (cycling: 30 min, 55%–60% peak power, 3 days/week) group (EX; n = 8) or a control group (CON; n = 10) for 3 months. Body composition (from dual-energy X-ray absorptiometry), physical fitness (peak oxygen uptake and the 6-minute walk test (6MWT)), lipid profile (triglycerides (TG), total cholesterol, high-density lipoprotein, and low-density lipoprotein (LDL)), and pro/antioxidant status (15-F2α-isoprostanes (F2-IsoP) and oxidized LDL in plasma; superoxide dismutase, glutathione peroxidase, and reduced/oxidized glutathione in erythrocytes) were determined at baseline and 3 months later. The intradialytic training protocol did not modify body composition but had significant effects on physical fitness, lipid profile, and pro/antioxidant status. Indeed, at 3 months: (i) performance on the 6MWT was increased in EX (+23.4%, p < 0.001) but did not change in CON, (ii) plasma TG were reduced in EX (–23%, p < 0.03) but were not modified in CON, and (iii) plasma F2-IsoP concentrations were lower in EX than in CON (–35.7%, p = 0.02). In conclusion, our results show that 30 min of intradialytic training, 3 times per week for 3 months, are enough to exert beneficial effects on the most sensitive and reliable marker of lipid peroxidation (IsoP) while improving CKD-associated disorders (lipid profile and physical fitness). Intradialytic aerobic cycling training represents a useful and easy strategy to reduce CKD-associated disorders. These results need to be confirmed with a larger randomized study.

Intra-dialytic exercise training: a pragmatic approach

This continuing education paper outlines the skills and knowledge required to plan, implement and evaluate a pragmatic approach to intra-dialytic exercise training.

AIM

The aim of this continuing education article is to enable the nephrology multi-disciplinary team (MDT) to plan, implement and evaluate the provision of intra-dialytic exercise training for patients receiving haemodialysis therapy.

LEARNING OUTCOMES

After reading this article the reader should be able to: Appreciate the level of evidence base for the clinical effectiveness of renal exercise rehabilitation and locate credible sources of research and educational information Understand and consider the need for appropriate evaluation and assessment outcomes as part of a renal rehabilitation plan Understand the components of exercise programming and prescription as part of an integrated renal rehabilitation plan Develop a sustainable longer term exercise and physical activity plan.

Associations of the antioxidant capacity and hemoglobin levels with functional physical performance of the upper and lower body limbs

Herein we considered the role of oxidative stress on deficiencies of functional physical performance that could affect a future pre-frailty condition. Using principal component analyses (PCA), we created new variables to better describe the functionality regarding the physical performance of the upper and lower body limbs. Gait speed and the Short Physical Performance Battery (SPPB) score were classified by PCA to describe functional performance of the lower body limbs. Variables describing the general physical status, including weekly consumption of kilocalories and the musculoskeletal index, were classified together with grip strength of the dominant hand as indicators of functional performance of the upper body limbs. An intimate association between the functional physical performance of the upper body limbs and the total antioxidant capacity was observed in older subjects. Low levels of total antioxidant capacity were found in women 76 years or younger with deficiencies in the physical performance of both upper and lower body limbs. Similarly, we observed a close association between the functional physical performance of the lower body limbs and the levels of hemoglobin. In particular, low levels of hemoglobin were mostly found in men older than 76 years of age, showing impaired functional physical performance. In addition, the physical performance of the lower body limbs was shown to be more important than that of the upper body limbs in the statistical association with pre-frailty in the elderly. Therefore, specific low levels of hemoglobin and deficient oxidative defense in the elderly could significantly affect the functional physical performance and future outcomes of pre-frailty.

Short-term changes after a weight reduction intervention in advanced diabetic nephropathy

BACKGROUND AND OBJECTIVES

Obesity precedes and is strongly linked to the development of type 2 diabetic nephropathy in most patients, yet little is known about the effects of weight reduction on this disease. This study aimed to establish proof of concept for the hypothesis that weight reduction ameliorates diabetic nephropathy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Six obese individuals with advanced diabetic nephropathy (estimated GFR <40 ml/min per 1.73 m(2), urine albumin excretion >30 mg/d) currently taking a renin-aldosterone axis inhibitor underwent a 12-week very low calorie ketogenic weight reduction diet with encouragement of exercise between March and September 2012. Albuminuria and other parameters of kidney health were the main outcome measures.

RESULTS

There was a 12% reduction in weight (median 118.5 versus 104.3 kg, P=0.03). The intervention was associated with a 36% reduction in albuminuria that did not reach statistical significance (2124 versus 1366 mg/24 h, P=0.08) and significant reductions in the filtration markers serum creatinine (3.54 versus 3.13 mg/dl, P<0.05) and cystatin C (2.79 versus 2.46 mg/l, P<0.05). Improvements were also noted for the diabetes markers fasting glucose (166 versus 131 mg/dl, P<0.05), fasting insulin (26.9 versus 10.4 μU/ml, P<0.05), and insulin resistance (9.6 versus 4.2, P=0.03). Physical function, general health, and the number of diabetes medications also showed statistically significant signs of improvement.

CONCLUSIONS

After a short-term intensive weight reduction intervention in patients with advanced diabetic nephropathy, improvements were observed in markers of glomerular filtration, diabetes status, and risk factors for kidney disease progression, as well as other general indicators of health and well-being.

Physical activity and exercise training: a relevant aspect of the dialysis patient's care

Sedentary lifestyle is frequent in hemodialysis patients whose physical capabilities are largely reduced when compared with healthy subjects, and evidence exists that sedentary dialysis patients are at higher risk of death as compared to non-sedentary ones. Dialysis patients may suffer from cardiovascular disease, diabetes, malnutrition, depression, which limits their exercise capacity; conversely, regular physical exercise may favor rehabilitation and correction of several cardiovascular, metabolic and nutritional abnormalities. Many observational, population-based studies show that the level of physical activity is related to quality of life and nutritional status, as well as to the survival probability. Intervention studies are instead lacking; a randomized controlled multicenter trial is in progress in Italy to assess the effect of home-based exercise programs on survival and hospitalization rate in stable dialysis patients. Implementation of physical activity should be one of the goals of dialysis care management, but several barriers prevent a widespread implementation of physical exercise programs in the dialysis units. A lack of patients' or care-givers' motivation or willingness, and structural or functional resources are the most frequent obstacles to exercise implementation. Since the hemodialysis population is quite heterogeneous for physical abilities and comorbidities, exercise in not for everyone and individual prescription is required for a correct and safe implementation of physical activity.

Assessing physical function and physical activity in patients with CKD

Patients with CKD are characterized by low levels of physical functioning, which, along with low physical activity, predict poor outcomes in those treated with dialysis. The hallmark of clinical care in geriatric practice and geriatric research is the orientation to and assessment of physical function and functional limitations. Although there is increasing interest in physical function and physical activity in patients with CKD, the nephrology field has not focused on this aspect of care. This paper provides an in-depth review of the measurement of physical function and physical activity. It focuses on physiologic impairments and physical performance limitations (impaired mobility and functional limitations). The review is based on established frameworks of physical impairment and functional limitations that have guided research in physical function in the aging population. Definitions and measures for physiologic impairments, physical performance limitations, self-reported function, and physical activity are presented. On the basis of the information presented, recommendations for incorporating routine assessment of physical function and encouragement for physical activity in clinical care are provided.

Walking and talking in maintenance hemodialysis patients

OBJECTIVES

To investigate whether there is a reduction in walking with the simultaneous performance of a cognitive task (ie, dual-task cost [DTC]) in persons undergoing hemodialysis (HD), and whether it is greater in persons undergoing HD compared with age-matched controls.

DESIGN

Cohort.

SETTING

University research laboratory.

PARTICIPANTS

Persons undergoing HD (n=14; 5 women, 9 men; mean age ± SD, 50.0±11.8y) and age-matched controls (n=14; 4 women, 10 men; mean age ± SD, 48.5±10.1y) participated in the investigation.

INTERVENTIONS

Not applicable.

MAIN OUTCOMES MEASURES

Participants walked at a self-selected pace on an electronic pathway, which recorded spatiotemporal parameters of gait, in 4 separate trials and completed a cognitive task in the last 2 trials. The DTC was quantified as the change in spatiotemporal parameters of gait from baseline to the cognitive trials.

RESULTS

The HD group had a greater decrease in walking function during the cognitive task, with DTC ranging from 6% to 14%. On average, walking velocity decreased to less than 1m/s in HD patients during the cognitive condition. Baseline walking velocity was found to be moderately correlated with the magnitude of DTC of cadence and step time (ρ=-.44 and .46; P values <.05).

CONCLUSIONS

Persons undergoing HD have greater interference between walking and talking compared with controls. Difficulty walking while thinking has implications for everyday life and may be related to the risk of falls. Further work is necessary to determine other contributing factors to elevated DTC in HD patients, and whether DTC can be reduced with targeted interventions.