Progressive Exercise for Anabolism in Kidney Disease (PEAK): A Randomized, Controlled Trial of Resistance Training during Hemodialysis

Intradialytic exercise in hemodialysis patients: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Hemodialysis (HD) patients are more inactive, leading to poor functional capacity and quality of life; this may be reversed with intradialytic exercise training. To systematically evaluate the efficacy and safety of intradialytic exercise for HD patients, we conducted a meta-analysis of the published randomized controlled trials.

DATA SOURCES AND METHODS

Medline, Embase, and Cochrane Central Register of Controlled Trials were systematically searched up to February, 2014. The reference lists of eligible studies and relevant reviews were also checked.

RESULTS

24 studies of 997 patients were included. Compared with control, intradialytic exercise significantly improve Kt/V (SMD = 0.27, 95% CI 0.01-0.53), peak oxygen consumption (VO(2peak)) (SMD = 0.53, 95% CI 0.30-0.76), and physical performance of physical function of life (SMD = 0.30, 95% CI 0.04-0.55). However, no significant improvements were found in the mental function of life. There was no significant difference with respect to musculoskeletal and cardiovascular complications between the intradialytic exercise groups and control groups. Further subgroup analysis found that, when the trial duration was more than 6 months, the intervention had significant effects on VO(2peak) (SMD = 0.89, 95% CI 0.56-1.22). However, when the trial duration was less than 6 months, the change of VO(2peak) was not significant (SMD = 0.19, 95% CI -0.13 to 0.51).

CONCLUSION

Intradialytic exercise can improve Kt/V, VO(2peak), and the physical quality of life, and intradialytic exercise is safe for HD patients. Therefore, we put forward the suggestion that clinical guideline be updated to inform clinicians on the benefits of intradialytic exercise on HD patients.

Resistance exercise: an effective strategy to reverse muscle wasting in hemodialysis patients?

Muscle wasting is a common complication afflicting maintenance hemodialysis (HD) patients, and it is associated with decreased muscle function, exercise performance, physical function, and quality of life. Meanwhile, numerous epidemiologic studies have consistently shown that greater muscle mass (ascertained by body anthropometry surrogates, body composition tests such as dual x-ray absorptiometry, and/or serum creatinine in patients with little to no residual kidney function) is associated with increased survival in this population. The pathophysiology of muscle wasting in HD patients is complex and may be caused by poor dietary intake, catabolic effects of dialysis therapy, hormonal alterations (e.g., decreased levels or resistance to anabolic hormones, increased levels of catabolic hormones), inflammation, metabolic acidosis, and concurrent comorbidities. Muscle disuse resulting from low physical activity is an important yet under-appreciated risk factor for muscle wasting. Intra-dialytic resistance exercise training has been suggested as a potential strategy to correct and/or prevent this complication in HD patients, but prior studies examining this exercise modality as an anabolic intervention have shown mixed results. In a recently published 12-week randomized controlled trial of a novel intra-dialytic progressive resistance exercise training (PRET) program vs. control therapy conducted in HD and non-HD patients, PRET resulted in increased muscle volume and strength in both groups. At this time, further study is needed to determine if anabolic improvements imparted by resistance exercise translates into improved physical function and quality of life, decreased hospitalization and mortality risk, and greater cost-effectiveness in HD patients.

Anabolic exercise in haemodialysis patients: a randomised controlled pilot study

BACKGROUND

The anabolic response to progressive resistance exercise training (PRET) in haemodialysis patients is unclear. This pilot efficacy study aimed to determine whether high-intensity intradialytic PRET could reverse atrophy and consequently improve strength and physical function in haemodialysis patients. A second aim was to compare any anabolic response to that of healthy participants completing the same program.

METHODS

In a single blind controlled study, 23 haemodialysis patients and 9 healthy individuals were randomly allocated to PRET or an attention control (SHAM) group. PRET completed high-intensity exercise leg extensions using novel equipment. SHAM completed low-intensity lower body stretching activities using ultra light resistance bands. Exercises were completed thrice weekly for 12 weeks, during dialysis in the haemodialysis patients. Outcomes included knee extensor muscle volume by magnetic resonance imaging, knee extensor strength by isometric dynamometer and lower body tests of physical function. Data were analysed by a per protocol method using between-group comparisons.

RESULTS

PRET elicited a statistically and clinically significant anabolic response in haemodialysis patients (PRET-SHAM, mean difference [95 % CI]: 193[63 to 324] cm(3)) that was very similar to the response in healthy participants (PRET-SHAM, 169[-41 to 379] cm(3)). PRET increased strength in both haemodialysis patients and healthy participants. In contrast, PRET only enhanced lower body functional capacity in the healthy participants.

CONCLUSIONS

Intradialytic PRET elicited a normal anabolic and strength response in haemodialysis patients. The lack of a change in functional capacity was surprising and warrants further investigation.

Dialysis exercise team: the way to sustain exercise programs in hemodialysis patients

Patients affected by end-stage renal disease (ESRD) show quite lower physical activity and exercise capacity when compared to healthy individuals. In addition, a sedentary lifestyle is favoured by lack of a specific counseling on exercise implementation in the nephrology care setting. Increasing physical activity level should represent a goal for every dialysis patient care management. Three crucial elements of clinical care may contribute to sustain a hemodialysis exercise program: a) involvement of exercise professionals, b) real commitment of nephrologists and dialysis professionals, c) individual patient adaptation of the exercise program. Dialysis staff have a crucial role to encourage and assist patients during intra-dialysis exercise, but other professionals should be included in the ideal "exercise team" for dialysis patients. Evaluation of general condition, comorbidities (especially cardiovascular), nutritional status and physical exercise capacity are mandatory to propose an exercise program, in either extra-dialysis or intra-dialysis setting. To this aim, nephrologist should lead a team of specialists and professionals including cardiologist, physiotherapist, exercise physiologist, renal dietician and nurse. In this scenario, dialysis nurses play a pivotal role since they guarantee a constant and direct approach. Unfortunately dialysis staff may often lack of information and formation about exercise management while they take care patients during the dialysis session. Building an effective exercise team, promoting the culture of exercise and increasing physical activity levels lead to a more complete and modern clinical care management of ESRD patients.

Vascular effects of exercise training in CKD: current evidence and pathophysiological mechanisms

Cardiovascular disease remains the main cause of morbidity and mortality in patients with CKD, an observation that cannot be explained by the coexistence of traditional risk factors alone. Recently, other mechanisms, such as alterations in nitric oxide bioavailability, impaired endothelial repair mechanisms, inflammation, and oxidative stress (all characteristic in CKD), have gained much attention as mediators for the increased cardiovascular risk. Regular physical training is a valuable nonpharmacological intervention for primary and secondary prevention of cardiovascular disease. Likewise, the benefits of exercise training on exercise capacity and quality of life are increasingly recognized in patients with CKD. Furthermore, exercise training could also influence potential reversible mechanisms involved in atherosclerosis and arteriosclerosis. After discussing briefly the general concepts of vascular disease in CKD, this review provides an overview of the current evidence for the effects of exercise training at both clinical and preclinical levels. It concludes with some practical considerations on exercise training in this specific patient group.

Relationship between lower extremity muscle strength and all-cause mortality in Japanese patients undergoing dialysis

BACKGROUND

Skeletal muscle wasting is common and insidious in patients who are undergoing hemodialysis. However, the association between lower extremity muscle strength and all-cause mortality remains unclear in this population.

OBJECTIVE

The purpose of this study was to investigate the prognostic significance of lower extremity muscle strength on 7-year survival in a cohort of patients who were clinically stable and undergoing hemodialysis.

DESIGN

A prospective cohort study was conducted.

METHODS

A total of 190 Japanese outpatients who were undergoing maintenance hemodialysis 3 times per week at a hemodialysis center were followed for up to 7 years. Lower extremity muscle strength was evaluated using a handheld dynamometer at the time of patient enrollment in the study. Muscle strength data were divided by dry weight and expressed as a percentage. A Cox proportional hazards regression model was used to assess the contribution of lower extremity muscle strength to all-cause mortality.

RESULTS

The median age (25th and 75th percentiles) of this study population was 64 years (57 and 72 years), 53.2% of the patients were women, and the time on hemodialysis was 39.0 months (15.9 and 110.5 months) at baseline. During a median follow-up of 36.0 months, there were 30 deaths. With a multivariate Cox model, the hazard ratio in the group with a knee extensor strength of <40% was 2.73 (95% confidence interval=1.14-6.52) compared with that in the ≥40% group.

LIMITATIONS

This was a small-scale observational study, and the mechanisms underlying the higher mortality risk in patients with poor muscle strength undergoing hemodialysis than in other patients undergoing hemodialysis remain to be elucidated.

CONCLUSIONS

Decreased lower extremity muscle strength was strongly associated with increased mortality risk in patients undergoing hemodialysis.

Resistance training in hemodialysis patients: a review

PURPOSE

Few studies have examined the role of resistance training (RT) in chronic kidney patients on hemodialysis (HD). This study reviews the literature about resistance exercise for patients on HD and describes protocols and clinical outcomes.

METHODS

A search of the MEDLINE database found 21 eligible publications, of which 14 studies applied only RT and 7 combined RT and aerobic training.

FINDINGS

Regarding the period of exercise training, 14 studies applied intradialytic exercise. The main outcome reported was muscle strength, which was assessed through knee strength and handgrip measures.

CONCLUSIONS

All studies reviewed presented at least one significant result in relation to biochemical parameters, physical capacity, strength, body composition, or quality of life.

CLINICAL RELEVANCE

This review demonstrates that RT improves muscle strength, some biochemical parameters, and quality of life of the HD patients.

Anabolic Effect of Exercise Training in People with End-Stage Renal Disease on Hemodialysis: A Systematic Review with Meta-analysis

PURPOSE

The primary purpose of this systematic review was to evaluate the anabolic effect of exercise intervention in adults with end-stage renal disease on hemodialysis (HD). The secondary objectives were to evaluate the influences of participant characteristics and exercise parameters on changes in muscle size.

METHODS

Electronic databases (Cochrane, CINAHL, EMBASE, PEDro, PubMed and SCOPUS) were searched from inception to November 2012. Randomized clinical trials published in English that included adults on HD undergoing an exercise intervention where muscle mass was measured as an outcome were included in this review. Two reviewers independently selected the studies, extracted data, and assessed risk of bias within the included studies. RESULTS were then combined by meta-analysis. The effect of exercises was determined using a standardized mean difference (SMD), expressed as Hedges' g, computed using a random effects model.

RESULTS

Seven SMDs extracted from five studies were included for final analysis. Strength training was used in all studies; one study used aerobic and mixed strength and aerobic training with two subgroups of participants. The overall effect of exercise on muscle mass was statistically significant (SMD: 0.272; 95% CI, 0.020-0.525).

CONCLUSIONS

Our results confirm a small but significant effect of strengthening exercise as an anabolic intervention to increase muscle mass. Exercise training should be included in routine management of people on maintenance HD. Although current results indicate that one in nine people on HD is likely to benefit from exercise intervention, parameters influencing these results require further research.

Intradialytic cycling in children and young adults on chronic hemodialysis

BACKGROUND

Intradialytic exercise has been poorly investigated in pediatric patients on chronic hemodialysis (HD). The aim of this study was to assess the acceptability, safety and efficacy of intradialytic exercise in children and young adults on HD.

METHODS

The intradialytic exercise program consisted of 30-min sessions of intra-HD exercise using a cycloergometer two to three times a week for 3 months. Study endpoints were the 6-min walking test (6MWT) distances, lung function, number of stands in the chair test, lower extremity strength (LES), anthropometry, dietary intake, dialysis adequacy, incidence of symptomatic sessions, biochemistry and left ventricular mass index.

RESULTS

Ten pediatric patients with a median age of 15.3 (range 9.1-24.2) years were enrolled. Two of these underwent kidney transplantation; the remaining eight completed the study and adapted well to the exercise program. At the end of the 3-month study period, all patients had significantly improved results for the 6MWT (+4.9 %; p < 0.05), chair test (+19 %; p < 0.05) and LES (+29.3 %; p < 0.05). Pre-HD albumin, creatinine and total protein levels and post-HD creatinine levels had also significantly improved. The incidence of symptomatic sessions did not increase during the study period. No adverse events occurred.

CONCLUSIONS

Based on our results, we conclude that a 30-min exercise program of intradialytic cycling is feasible for the majority of pediatric patients on chronic HD and will be well accepted. Such an exercise program can lead to a significant improvement in the exercise capacity of this patient population.

Measurement of skeletal muscle radiation attenuation and basis of its biological variation

Skeletal muscle contains intramyocellular lipid droplets within the cytoplasm of myocytes as well as intermuscular adipocytes. These depots exhibit physiological and pathological variation which has been revealed with the advent of diagnostic imaging approaches: magnetic resonance (MR) imaging, MR spectroscopy and computed tomography (CT). CT uses computer-processed X-rays and is now being applied in muscle physiology research. The purpose of this review is to present CT methodologies and summarize factors that influence muscle radiation attenuation, a parameter which is inversely related to muscle fat content. Pre-defined radiation attenuation ranges are used to demarcate intermuscular adipose tissue [from −190 to −30 Hounsfield units (HU)] and muscle (−29 HU to +150 HU). Within the latter range, the mean muscle radiation attenuation [muscle (radio) density] is reported. Inconsistent criteria for the upper and lower HU cut-offs used to characterize muscle attenuation limit comparisons between investigations. This area of research would benefit from standardized criteria for reporting muscle attenuation. Available evidence suggests that muscle attenuation is plastic with physiological variation induced by the process of ageing, as well as by aerobic training, which probably reflects accumulation of lipids to fuel aerobic work. Pathological variation in muscle attenuation reflects excess fat deposition in the tissue and is observed in people with obesity, diabetes type II, myositis, osteoarthritis, spinal stenosis and cancer. A poor prognosis and different types of morbidity are predicted by the presence of reduced mean muscle attenuation values in patients with these conditions; however, the biological features of muscle with these characteristics require further investigation.

Effects of progressive resistance training on body composition, physical fitness and quality of life of patients on hemodialysis

PURPOSE

To investigate the effect of progressive resistance training (PRT) on body composition, physical fitness, quality of life, lipid and nutritional profile of patients on hemodialysis (HD).

METHODS

A non equivalent comparison group pretest and posttest design study was used with 40 participants who were randomly assigned to the exercise group (20 participants) and the comparison group (20 participants). The exercise group received PRT for 30 minutes per session, 3 sessions a week, for 12 weeks, while the comparison group received usual care. The PRT consisted of upper and lower body exercises using elastic bands and sandbags. Outcome measures evaluated were: body composition, physical fitness, quality of life, and lipid profile.

RESULTS

Skeletal muscle mass, grip, leg muscle strength, and quality of life all improved significantly in the exercise group. Body fat rate, total cholesterol and triglyceride rate decreased significantly in the exercise group.

CONCLUSION

These results suggest that PRT improves body composition, physical fitness, quality of life, and lipid profile of patients on HD. PRT using elastic bands and sandbags can be utilized as part of a regular care plan for these patients.

The effect of intradialytic aerobic exercise on dialysis efficacy in hemodialysis patients: a randomized controlled trial

OBJECTIVE

This study was conducted to determine the impact of an 8-week intradialytic exercise program (consisting of 15 minutes low-intensity exercise during the first 2 hours of dialysis) on dialysis efficacy.

METHODS

In an open randomized controlled trial, a total of 50 clinically stable hemodialysis patients were enrolled into the study and randomly allocated into two groups: the aerobic exercise group (n=25) and the control group (n=25). Aerobic exercises were done in the intervention group for 15 min/day, three times a week for 2 months. The dialysis efficacy was assessed prior to and at the end of each month of the program.

RESULTS

The efficacy of dialysis increased at the end of the first month and remained elevated for the duration of the program in the exercise group (p<0.05).

CONCLUSION

A simplified aerobic exercise program has increased the efficacy of dialysis and may be considered as a safe, complementary and effective modality for hemodialysis patients.

Physical activity for the prevention and treatment of major chronic disease: an overview of systematic reviews

BACKGROUND

The evidence that higher levels of physical activity and/or lower levels of physical inactivity are associated with beneficial health-related outcomes stems mainly from observational studies. Findings from these studies often differ from randomised controlled trials and systematic reviews currently demonstrate mixed results, due partly to heterogeneity in physical activity interventions, methodologies used and populations studied. As a result, translation into clinical practice has been difficult. It is therefore essential that an overview is carried out to compare and contrast systematic reviews, and to identify those physical activity interventions that are the most effective in preventing and/or treating major chronic disease. This protocol has been registered on PROSPERO 2013: CRD42013003523.

METHODS

We will carry out an overview of Cochrane systematic reviews. We will search the Cochrane Database of Systematic Reviews for systematic reviews of randomised controlled trials that have a primary focus on disease-related outcomes. We will restrict reviews to those in selected major chronic diseases. Two authors will independently screen search outputs, select studies, extract data and assess the quality of included reviews using the assessment of multiple systematic reviews tool; all discrepancies will be resolved by discussing and reaching a consensus, or by arbitration with a third author. The data extraction form will summarise key information from each review, including details of the population(s) (for example, disease condition), the context (for example, prevention, treatment or management), the participants, the intervention(s), the comparison(s) and the outcomes. The primary outcomes of interest are the prevention of chronic disease and/or improved outcomes, in the treatment or management of chronic disease. These outcomes will be summarised and presented for individual chronic diseases (for example, any change in blood pressure in hypertension or glucose control in diabetes). Secondary outcomes of interest are to describe the structure and delivery of physical activity interventions across chronic disease conditions and adverse events associated with physical activity.

DISCUSSION

We anticipate that our results could inform researchers, guideline groups and policymakers of the most efficacious physical activity interventions in preventing and/or managing major chronic disease.

Cancer cachexia prevention via physical exercise: molecular mechanisms

Cancer cachexia is a debilitating consequence of disease progression, characterised by the significant weight loss through the catabolism of both skeletal muscle and adipose tissue, leading to a reduced mobility and muscle function, fatigue, impaired quality of life and ultimately death occurring with 25-30 % total body weight loss. Degradation of proteins and decreased protein synthesis contributes to catabolism of skeletal muscle, while the loss of adipose tissue results mainly from enhanced lipolysis. These mechanisms appear to be at least, in part, mediated by systemic inflammation. Exercise, by virtue of its anti-inflammatory effect, is shown to be effective at counteracting the muscle catabolism by increasing protein synthesis and reducing protein degradation, thus successfully improving muscle strength, physical function and quality of life in patients with non-cancer-related cachexia. Therefore, by implementing appropriate exercise interventions upon diagnosis and at various stages of treatment, it may be possible to reverse protein degradation, while increasing protein synthesis and lean body mass, thus counteracting the wasting seen in cachexia.

Natural history of skeletal muscle mass changes in chronic kidney disease stage 4 and 5 patients: an observational study

Cross-sectional studies in dialysis demonstrate muscle wasting associated with loss of function, increased morbidity and mortality. The relative drivers are poorly understood. There is a paucity of data regarding interval change in muscle in pre-dialysis and dialysis-dependant patients. This study aimed to examine muscle and fat mass change and elucidate associations with muscle wasting in advanced CKD. 134 patients were studied (60 HD, 28 PD, 46 CKD 4-5) and followed up for two years. Groups were similar in age, sex and diabetes prevalence. Soft tissue cross-sectional area (CSA) was measured annually on 3 occasions by a standardised multi-slice CT thigh. Potential determinants of muscle and fat CSA were assessed. Functional ability was assessed by sit-to-stand testing. 88 patients completed follow-up (40 HD, 16 PD, 32 CKD). There was a significant difference in percentage change in muscle CSA (MCSA) over year 1, dependant on treatment modality (χ(2) = 6.46; p = 0.039). Muscle loss was most pronounced in pre-dialysis patients. Muscle loss during year 1 was partially reversed in year 2 in 39%. Incident dialysis patients significantly lost MCSA during the year which they commenced dialysis, but not the subsequent year. Baseline MCSA, change in MCSA during year 1 and dialysis modality predicted year 2 change in MCSA (adjusted R(2) = 0.77, p<0.001). There was no correlation between muscle or fat CSA change and any other factors. MCSA correlated with functional testing, although MCSA change correlated poorly with change in functional ability. These data demonstrate marked variability in MCSA over 2 years. Loss of MCSA in both pre-dialysis and established dialysis patients is reversible. Factors previously cross-sectionally shown to correlate with MCSA did not correlate with wasting progression. The higher rate of muscle loss in undialysed CKD patients, and its reversal after dialysis commencement, suggests that conventional indicators may not result in optimal timing of dialysis initiation.

Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism

Protein energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with adverse clinical outcomes, especially in individuals receiving maintenance dialysis therapy. A multitude of factors can affect the nutritional and metabolic status of CKD patients requiring a combination of therapeutic maneuvers to prevent or reverse protein and energy depletion. These include optimizing dietary nutrient intake, appropriate treatment of metabolic disturbances such as metabolic acidosis, systemic inflammation, and hormonal deficiencies, and prescribing optimized dialytic regimens. In patients where oral dietary intake from regular meals cannot maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is shown to be effective in replenishing protein and energy stores. In clinical practice, the advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic strategies such as anabolic steroids, growth hormone, and exercise, in combination with nutritional supplementation or alone, have been shown to improve protein stores and represent potential additional approaches for the treatment of PEW. Appetite stimulants, anti-inflammatory interventions, and newer anabolic agents are emerging as novel therapies. While numerous epidemiological data suggest that an improvement in biomarkers of nutritional status is associated with improved survival, there are no large randomized clinical trials that have tested the effectiveness of nutritional interventions on mortality and morbidity.

Inflammatory factors and exercise in chronic kidney disease

Patients with chronic kidney disease frequently present with chronic elevations in markers of inflammation, a condition that appears to be exacerbated by disease progression and onset of haemodialysis. Systemic inflammation is interlinked with malnutrition and muscle protein wasting and is implicated in a number of morbidities including cardiovascular disease: the most common cause of mortality in this population. Research in the general population and other chronic disease cohorts suggests that an increase in habitual activity levels over a prolonged period may help redress basal increases in systemic inflammation. Furthermore, those populations with the highest baseline levels of systemic inflammation appear to have the greatest improvements from training. On the whole, the activity levels of the chronic kidney disease population reflect a sedentary lifestyle, indicating the potential for increasing physical activity and observing health benefits. This review explores the current literature investigating exercise and inflammatory factors in the chronic kidney disease population and then attempts to explain the contradictory findings and suggests where future research is required.

Combined walking exercise and alkali therapy in patients with CKD4-5 regulates intramuscular free amino acid pools and ubiquitin E3 ligase expression

Muscle-wasting in chronic kidney disease (CKD) arises from several factors including sedentary behaviour and metabolic acidosis. Exercise is potentially beneficial but might worsen acidosis through exercise-induced lactic acidosis. We studied the chronic effects of exercise in CKD stage 4-5 patients (brisk walking, 30 min, 5 times/week), and non-exercising controls; each group receiving standard oral bicarbonate (STD), or additional bicarbonate (XS) (Total n = 26; Exercising + STD n = 9; Exercising +XS n = 6; Control + STD n = 8; Control + XS n = 3). Blood and vastus lateralis biopsies were drawn at baseline and 6 months. The rise in blood lactate in submaximal treadmill tests was suppressed in the Exercising + XS group. After 6 months, intramuscular free amino acids (including the branched chain amino acids) in the Exercising + STD group showed a striking chronic depletion. This did not occur in the Exercising + XS group. The effect in Exercising + XS patients was accompanied by reduced transcription of ubiquitin E3-ligase MuRF1 which activates proteolysis via the ubiquitin-proteasome pathway. Other anabolic indicators (Akt activation and suppression of the 14 kDa actin catabolic marker) were unaffected in Exercising + XS patients. Possibly because of this, overall suppression of myofibrillar proteolysis (3-methylhistidine output) was not observed. It is suggested that alkali effects in exercisers arose by countering exercise-induced acidosis. Whether further anabolic effects are attainable on combining alkali with enhanced exercise (e.g. resistance exercise) merits further investigation.

Frailty and protein-energy wasting in elderly patients with end stage kidney disease

Older people constitute an increasingly greater proportion of patients with advanced CKD, including those patients undergoing maintenance dialysis treatment. Frailty is a biologic syndrome of decreased reserve and resistance to stressors that results from cumulative declines across multiple physiologic systems and causes vulnerability to adverse outcomes. Frailty is common in elderly CKD patients, and it may be associated with protein-energy wasting (PEW), sarcopenia, dynapenia, and other complications of CKD. Causes of frailty with or without PEW in the elderly with CKD can be classified into three categories: causes primarily caused by aging per se, advanced CKD per se, or a combination of both conditions. Frailty and PEW in elderly CKD patients are associated with impaired physical performance, disability, poorer quality of life, and reduced survival. Prevention and treatment of these conditions in the elderly CKD patients often require a multifaceted approach. Here, we examine the causes and consequences of these conditions and examine the interplay between frailty and PEW in elderly CKD patients.

Habitual physical activity measured by accelerometer and survival in maintenance hemodialysis patients

BACKGROUND AND OBJECTIVES

The association between mortality and physical activity based on self-report questionnaire in hemodialysis patients has been reported previously. However, because self-report is a subjective assessment, evaluating true physical activity is difficult. This study investigated the prognostic significance of habitual physical activity on 7-year survival in a cohort of clinically stable and adequately dialyzed patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 202 Japanese outpatients who were undergoing maintenance hemodialysis three times per week at the hemodialysis center of Sagami Junkanki Clinic (Japan) from October 2002 to February 2012 were followed for up to 7 years. Physical activity was evaluated using an accelerometer at study entry and is expressed as the amount of time a patient engaged in physical activity on nondialysis days. Cox proportional hazard regression was used to assess the contribution of habitual physical activity to all-cause mortality.

RESULTS

The median patient age was 64 (25th, 75th percentiles, 57, 72) years, 52.0% of the patients were women, and the median time on hemodialysis was 40.0 (25th, 75th percentiles, 16.8, 119.3) months at baseline. During a median follow-up of 45 months, 34 patients died. On multivariable analysis, the hazard ratio for all-cause mortality per 10 min/d increase in physical activity was 0.78 (95% confidence interval, 0.66-0.92; P=0.002).

CONCLUSIONS

Engaging in habitual physical activity among outpatients undergoing maintenance hemodialysis was associated with decreased mortality risk.

The effects of high-load strength training with protein- or nonprotein-containing nutritional supplementation in patients undergoing dialysis

OBJECTIVE

The aim of this study was to investigate the effects of high-load strength training and protein intake in patients undergoing dialysis with a focus on muscle strength, physical performance, and muscle morphology.

DESIGN

This was a randomized controlled study conducted in three dialysis centers.

SUBJECTS

Subjects for the study included 29 patients undergoing dialysis.

INTERVENTION

The participants went through a control period of 16 weeks before completing 16 weeks of strength training. Before the training period, the participants were randomly assigned to receive a protein or a nonprotein drink after every training session.

MAIN OUTCOME MEASURE

Muscle strength and power were tested using the good strength equipment and the leg extensor power rig. Physical performance and function were assessed using a chair stand test and the Short Form 36 questionnaire. Muscle fiber type size and composition were analyzed in biopsies obtained from the m. vastus lateralis.

RESULTS

All variables remained unchanged during the control period. After training, muscle strength and power, physical performance, and physical function increased significantly. Muscle fiber composition was changed by a relative decrease in type 2x muscle fiber number whereas muscle size at the fiber level was unchanged. There were no effects of combining the training with protein intake.

CONCLUSIONS

High-load strength training is associated with improvements in muscle strength and power, physical performance, and quality of life. The effects were surprisingly not associated with muscle hypertrophy, and the results did not reveal any additional benefit of combining the training with protein intake. The positive results in muscle strength and physical performance have clinically relevant implications in the treatment of patients undergoing dialysis.

Exercise training in chronic kidney disease patients

Chronic kidney disease (CKD) is a major public health problem that affects an estimated 1.7 million Australians. Patients with CKD commonly progress to end-stage kidney disease (ESKD) requiring dialysis and/or kidney transplantation. They are at high risk of cardiovascular disease and many die from this prior to reaching ESKD. Few therapies are available to slow CKD progression and reduce cardiovascular morbidity and mortality. The benefit of exercise training has been well demonstrated in a range of disease conditions including ESKD and was recently highlighted by a systematic review in haemodialysis patients and a recent Cochrane review of all stages of CKD. However, the effects of exercise training in patients with CKD have not been extensively investigated. Our systematic search of the literature found only ten clinical trials in this area. The aim of this review is to review these studies, and to discuss the findings, safety considerations and suggest future areas of research. Overall, the majority of the studies are small, non-randomized, non-controlled trials. They have found that exercise training can increase exercise capacity, improve muscle strength and function, decrease blood pressure, and improve inflammation and oxidative stress biomarkers. The effects of exercise training on kidney function, cardiovascular disease and quality of life are unknown. Studies are needed to answer these questions and develop evidence-based exercise training guidelines for individuals with CKD.

Inflammation, diabetes, and chronic kidney disease: role of aerobic capacity

The persistent inflammatory state is common in diabetes and chronic kidney disease (CKD). These patients present exercise intolerance and increased arterial stiffness. Long-term aerobic exercise has been associated with better arterial compliance, antidiabetic and antiinflammatory benefits. We assessed the hypothesis that in patients with diabetes and CKD, better aerobic capacity is associated with less inflammatory state and arterial stiffness. Thirty-nine CKD patients (17 in hemodialysis) were evaluated. According to CKD etiology two patient groups were obtained: group of diabetics (GD) was formed by 11 patients and nondiabetics (GND) formed by 28 patients. Central blood pressure and arterial stiffness were evaluated by Sphygmocor device. Carotida intima-media thickness (CA-IMT) was evaluated by ultrasonography. Aerobic capacity was measured by estimated VO₂max according to treadmill test by Bruce protocol. The GD showed a higher frequency of C-reactive protein above laboratory cutoff (P = 0.044), higher frequency of male gender, and a non significant higher value of VO₂max (P = 0.099). The CA-IMT was similar. Only better aerobic capacity was associated with lower frequency of high C-reactive protein when adjusted to diabetes and gender in a logistic regression model. In conclusion, aerobic capacity was associated with inflammatory state, in CKD patients, independently of diabetes presence.

Sarcopenia: a major challenge in elderly patients with end-stage renal disease

Sarcopenia is a condition of multifaceted etiology arising in many elderly people. In patients with chronic kidney, the loss of muscle mass is much more intensive and the first signs of sarcopenia are observed in younger patients than it is expected. It is associated with the whole-body protein-energy deficiency called protein-energy wasting (PEW). It seems to be one of the major factors limiting patient's autonomy as well as decreasing the quality of life. If it cannot be treated with the simple methods requiring some knowledge and devotion, we will fail to save patients who die due to cardiovascular disease and infection, despite proper conduction of renal replacement therapy. Many factors influencing the risk of sarcopenia development have been evaluated in number of studies. Many studies also were conducted to assess the efficacy of different therapeutic strategies (diet, physical activity, hormones). Nevertheless, there is still no consensus on treatment the patients with PEW. Therefore, in the paper we present the reasons and pathophysiology of sarcopenia as an important element of protein energy wasting (PEW) in elderly patients suffering from chronic kidney disease. We also analyze possible options for treatment according to up-to-date knowledge.

An appraisal of rehabilitation regimes used for improving functional outcome after total hip replacement surgery

This study aimed to systematically review the literature with regards to studies of rehabilitation programmes that have tried to improve function after total hip replacement (THR) surgery. 15 randomised controlled trials were identified of which 11 were centre-based, 2 were home based and 2 were trials comparing home and centre based interventions. The use of a progressive resistance training (PRT) programme led to significant improvement in muscle strength and function if the intervention was carried out early (< 1 month following surgery) in a centre (6/11 centre-based studies used PRT), or late (> 1 month following surgery) in a home based setting (2/2 home based studies used PRT). In direct comparison, there was no difference in functional measures between home and centre based programmes (2 studies), with PRT not included in the regimes prescribed. A limitation of the majority of these intervention studies was the short period of follow up. Centre based program delivery is expensive as high costs are associated with supervision, facility provision, and transport of patients. Early interventions are important to counteract the deficit in muscle strength in the affected limb, as well as persistent atrophy that exists around the affected hip at 2 years post-operatively. Studies of early home-based regimes featuring PRT with long term follow up are needed to address the problems currently associated with rehabilitation following THR.

[Is there a place for the physical activity in the prevention of the fractures of chronic kidney disease patients?]

The risk of non-traumatic fractures is greatly increased in kidney disease patients and well demonstrated in dialysis patients. If osteoporosis plays a major role in the general population, in chronic kidney disease renal osteodystrophy is associated with neurological and muscular disorders, which probably worsen the risk. The decrease in physical activity is a factor contributing to the loss of bone mass and the initiation of a rehabilitation program improves the prognosis. Despite the association between chronic renal disease and sedentary lifestyle, the relationship between physical inactivity and bones in dialysis patients and the effect of increased activity programs, are not well documented in the literature.

Exercise training for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a worldwide public health problem. In the National Kidney Foundation Disease Outcomes Quality Initiative guidelines it is stressed that lifestyle issues such as physical activity should be seen as cornerstones of the therapy. The physical fitness in adults with CKD is so reduced that it impinges on ability and capacity to perform activities in everyday life and occupational tasks. An increasing number of studies have been published regarding health effects of various regular exercise programmes in adults with CKD and in renal transplant patients.

OBJECTIVES

We aimed to: 1) assess the effects of regular exercise in adults with CKD and kidney transplant patients; and 2) determine how the exercise programme should be designed (e.g. type, duration, intensity, frequency of exercise) to be able to affect physical fitness and functioning, level of physical activity, cardiovascular dimensions, nutrition, lipids, glucose metabolism, systemic inflammation, muscle morphology and morphometrics, dropout rates, compliance, adverse events and mortality.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, CENTRAL, MEDLINE, EMBASE, CINAHL, Web of Science, Biosis, Pedro, Amed, AgeLine, PsycINFO and KoreaMed. We also handsearched reference lists of review articles and included studies, conference proceeding's abstracts. There were no language restrictions.Date of last search: May 2010.

SELECTION CRITERIA

We included any randomised controlled trial (RCT) enrolling adults with CKD or kidney transplant recipients undergoing any type of physical exercise intervention undertaken for eight weeks or more. Studies using less than eight weeks exercise, those only recommending an increase in physical activity, and studies in which co-interventions are not applied or given to both groups were excluded.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of study and data quality were performed independently by the two authors. Continuous outcome data are presented as standardised mean difference (SMD) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

Forty-five studies, randomising 1863 participants were included in this review. Thirty two studies presented data that could be meta-analysed. Types of exercise training included cardiovascular training, mixed cardiovascular and resistance training, resistance-only training and yoga. Some studies used supervised exercise interventions and others used unsupervised interventions. Exercise intensity was classed as 'high' or 'low', duration of individual exercise sessions ranged from 20 minutes/session to 110 minutes/session, and study duration was from two to 18 months. Seventeen per cent of studies were classed as having an overall low risk of bias, 33% as moderate, and 49% as having a high risk of bias.The results shows that regular exercise significantly improved: 1) physical fitness (aerobic capacity, 24 studies, 847 participants: SMD -0.56, 95% CI -0.70 to -0.42; walking capacity, 7 studies, 191 participants: SMD -0.36, 95% CI-0.65 to -0.06); 2) cardiovascular dimensions (resting diastolic blood pressure, 11 studies, 419 participants: MD 2.32 mm Hg, 95% CI 0.59 to 4.05; resting systolic blood pressure, 9 studies, 347 participants: MD 6.08 mm Hg, 95% CI 2.15 to 10.12; heart rate, 11 studies, 229 participants: MD 6 bpm, 95% CI 10 to 2); 3) some nutritional parameters (albumin, 3 studies, 111 participants: MD -2.28 g/L, 95% CI -4.25 to -0.32; pre-albumin, 3 studies, 111 participants: MD - 44.02 mg/L, 95% CI -71.52 to -16.53; energy intake, 4 studies, 97 participants: SMD -0.47, 95% CI -0.88 to -0.05); and 4) health-related quality of life. Results also showed how exercise should be designed in order to optimise the effect. Other outcomes had insufficient evidence.

AUTHORS' CONCLUSIONS

There is evidence for significant beneficial effects of regular exercise on physical fitness, walking capacity, cardiovascular dimensions (e.g. blood pressure and heart rate), health-related quality of life and some nutritional parameters in adults with CKD. Other outcomes had insufficient evidence due to the lack of data from RCTs. The design of the exercise intervention causes difference in effect size and should be considered when prescribing exercise with the aim of affecting a certain outcome. Future RCTs should focus more on the effects of resistance training interventions or mixed cardiovascular- and resistance training as these exercise types have not been studied as much as cardiovascular exercise.

Intradialytic exercise programs for hemodialysis patients

Although it is widely accepted that exercise is beneficial in patients with end-stage renal disease as in the general population, it is not easy to incorporate exercise programs into routine clinical practice. This review aimed to investigate the beneficial effects of exercise during hemodialysis and also to introduce various intradialytic exercise programs and their advantages as a first step in combining exercise programs into clinical practice. Aerobic and resistance exercise are beneficial not only in improving physical functioning, including maximal oxygen uptake and muscle strength, but also in improving anthropometrics, nutritional status, hematological indexes, inflammatory cytokines, depression, and health-related quality of life. However, it is not clear whether the beneficial effects of exercise are limited to only relatively healthy dialysis patients. Therefore, the effects of individualized exercise programs for elderly patients or patients with comorbid conditions need to be studied further.

Morphological, electrophysiological, and metabolic characteristics of skeletal muscle in people with end-stage renal disease: a critical review

PURPOSE

Fatigue is one of the most frequent debilitating symptoms reported by people with end-stage renal disease (ESRD) on haemodialysis (HD) therapy. A wide range of underlying abnormalities, including skeletal muscle weakness, have been implicated as causes of this fatigue. Skeletal muscle weakness is well established in this population, and such muscle weakness is amenable to physical therapy treatment. The purpose of this review was to identify morphological, electrophysiological, and metabolic characteristics of skeletal muscles in people with ESRD/HD that may cause skeletal muscle weakness.

METHOD

Electronic databases were searched for relevant literature from inception to March 2010. Inclusion criteria were English language; adult subjects with ESRD/HD; and the use of muscle biopsy, electromyography, and nuclear magnetic spectroscopy ((31)P-NMRS) techniques to evaluate muscle characteristics.

RESULTS

In total, 38 studies were included. All studies of morphological characteristics reported type II fibre atrophy. Electrophysiological characteristics included both neuropathic and myopathic skeletal muscle changes. Studies of metabolic characteristics revealed higher cytosolic inorganic phosphate levels and reduced effective muscle mass.

CONCLUSION

The results indicate an array of changes in the morphological, electrophysiological, and metabolic characteristics of skeletal muscle structure in people with ESRD/HD that may lead to muscle weakness.

Test-retest reliability and minimal detectable change scores for sit-to-stand-to-sit tests, the six-minute walk test, the one-leg heel-rise test, and handgrip strength in people undergoing hemodialysis

BACKGROUND

Determining the relative and absolute reliability of outcomes of physical performance tests for people undergoing hemodialysis is necessary to discriminate between the true effects of exercise interventions and the inherent variability of this cohort.

OBJECTIVE

The aims of this study were to assess the relative reliability of sit-to-stand-to-sit tests (the STS-10, which measures the time [in seconds] required to complete 10 full stands from a sitting position, and the STS-60, which measures the number of repetitions achieved in 60 seconds), the Six-Minute Walk Test (6MWT), the one-leg heel-rise test, and the handgrip strength test and to calculate minimal detectable change (MDC) scores in people undergoing hemodialysis.

DESIGN

This study was a prospective, nonexperimental investigation.

METHODS

Thirty-nine people undergoing hemodialysis at 2 clinics in Spain were contacted. Study participants performed the STS-10 (n=37), the STS-60 (n=37), and the 6MWT (n=36). At one of the settings, the participants also performed the one-leg heel-rise test (n=21) and the handgrip strength test (n=12) on both the right and the left sides. Participants attended 2 testing sessions 1 to 2 weeks apart.

RESULTS

High intraclass correlation coefficients (≥.88) were found for all tests, suggesting good relative reliability. The MDC scores at 90% confidence intervals were as follows: 8.4 seconds for the STS-10, 4 repetitions for the STS-60, 66.3 m for the 6MWT, 3.4 kg for handgrip strength (force-generating capacity), 3.7 repetitions for the one-leg heel-rise test with the right leg, and 5.2 repetitions for the one-leg heel-rise test with the left leg. Limitations A limited sample of patients was used in this study.

CONCLUSIONS

The STS-16, STS-60, 6MWT, one-leg heel rise test, and handgrip strength test are reliable outcome measures. The MDC scores at 90% confidence intervals for these tests will help to determine whether a change is due to error or to an intervention.

Benefits of wellness interventions for persons with chronic and disabling conditions: a review of the evidence

BACKGROUND

Persons living with the effects of chronic and disabling conditions are often at increased risk for the development of secondary conditions and disabilities that can lead to further decline in health status, independence, functional status, life satisfaction, and overall quality of life.

OBJECTIVE

The purpose of this study was to review the evidence for the benefits of wellness/health promotion interventions for persons with chronic and disabling conditions.

METHODS

The authors conducted a Medline search (1990-2007) using terms related to wellness and health promotion cross-referenced with general terms for chronic and disabling conditions, as well as 15 specific chronic and/or disabling conditions (e.g., multiple sclerosis, spinal cord injury). Selection of studies was limited to those published in English that reported randomized controlled trails or prospective studies that involved adult human subjects with a chronic and/or disabling condition. All selected studies focused on some aspect of a wellness or health promotion intervention and involved a comparison or control group. Of the 5,847 studies initially identified in the search using medical subject heading terms, 190 met the criteria for full review. Data were extracted from these publications and summarized using descriptive statistics.

RESULTS

Almost all studies (95%) explored the effects of wellness intervention in a sample diagnosed with a single condition (e.g., cancer, stroke, arthritis). Although the mean sample size was 100, the range in sample size varied widely (6-688); 25% of the studies had sample of 30 or fewer. Almost all studies (89.5%) reported positive effects of the wellness intervention, although the delivery and content of interventions as well as the measurement of outcomes, varied greatly.

CONCLUSIONS

Our findings support an immediate post-intervention positive impact of wellness interventions across persons with a wide variety of chronic and disabling conditions. Future research that clearly specifies primary study outcomes and follows the CONSORT guidelines will strengthen future reviews of the evidence and facilitate application of the evidence of practice.

Exercise as an anabolic intervention in patients with end-stage renal disease

Muscle wasting and accompanying structural derangements leading to abnormalities in muscle function, exercise performance, and physical activity are common in patients with end-stage renal disease. Therefore, several studies have been performed examining the effects of exercise in this particular patient population. Most of the studies have assessed the effects of cardiopulmonary fitness training, whereas a few have examined the role of resistance (i.e., strength) training. Despite the proven efficacy of resistance exercise as an anabolic intervention in the otherwise healthy elderly population and certain chronic disease states, recent studies in patients on maintenance hemodialysis have not been encouraging in terms of long-term improvements in markers of muscle mass. Preliminary studies indicated that a combination of simultaneous exercise and nutritional supplementation could augment the anabolic effects of exercise, at least in the acute setting. However, a recent randomized clinical trial failed to show further benefits of additional resistance exercise on long-term somatic protein accretion above and beyond nutritional supplementation alone. Further research is necessary to both understand the observed lack of obvious benefits and strategies to improve the exercise regimens in patients with end-stage renal disease.

Preserving residual renal function in dialysis patients: an update on evidence to assist clinical decision making

It has been documented that preservation of residual renal function in dialysis patients improves quality of life as well as survival. Clinical trials on strategies to preserve residual renal function are clearly lacking. While waiting for more results from clinical trials, patients will benefit from clinicians being aware of available knowledge. The aim of this review was to offer an update on current evidence assisting doctors in clinical practice.