Physical inactivity and protein energy wasting play independent roles in muscle weakness in maintenance haemodialysis patients

Exercise for patients with chronic kidney disease: from cells to systems to function

Chronic kidney disease (CKD) is among the leading causes of death and disability, affecting an estimated 800 million adults globally. The underlying pathophysiology of CKD is complex creating challenges to its management. Primary risk factors for the development and progression of CKD include diabetes mellitus, hypertension, age, obesity, diet, inflammation, and physical inactivity. The high prevalence of diabetes and hypertension in patients with CKD increases the risk for secondary consequences such as cardiovascular disease and peripheral neuropathy. Moreover, the increased prevalence of obesity and chronic levels of systemic inflammation in CKD have downstream effects on critical cellular functions regulating homeostasis. The combination of these factors results in the deterioration of health and functional capacity in those living with CKD. Exercise offers protective benefits for the maintenance of health and function with age, even in the presence of CKD. Despite accumulating data supporting the implementation of exercise for the promotion of health and function in patients with CKD, a thorough description of the responses and adaptations to exercise at the cellular, system, and whole body levels is currently lacking. Therefore, the purpose of this review is to provide an up-to-date comprehensive review of the effects of exercise training on vascular endothelial progenitor cells at the cellular level; cardiovascular, musculoskeletal, and neural factors at the system level; and physical function, frailty, and fatigability at the whole body level in patients with CKD.

The Impact of Combined Nutrition and Exercise Interventions in Patients with Chronic Kidney Disease

Combined nutrition and exercise interventions potentially improve protein-energy wasting/malnutrition-related outcomes in patients with chronic kidney disease (CKD). The aim was to systematically review the effect of combined interventions on nutritional status, muscle strength, physical performance and QoL. MEDLINE, Cochrane, Embase, Web of Science and Google Scholar were searched for studies up to the date of July 2023. Methodological quality was appraised with the Cochrane risk-of-bias tool. Ten randomized controlled trials (nine publications) were included (334 patients). No differences were observed in body mass index, lean body mass or leg strength. An improvement was found in the six-minute walk test (6-MWT) (n = 3, MD 27.2, 95%CI [7 to 48], p = 0.008), but not in the timed up-and-go test. No effect was found on QoL. A positive impact on 6-MWT was observed, but no improvements were detected in nutritional status, muscle strength or QoL. Concerns about reliability and generalizability arise due to limited statistical power and study heterogeneity of the studies included.

Muscle strength performed better than muscle mass in identifying cognitive impairment risk in maintenance hemodialysis patients

OBJECTIVES

The association between muscle mass and cognitive impairment (CI) is conflicting. We aimed to evaluate and compare the associations of muscle strength, muscle mass and CI risk in maintenance hemodialysis (MHD) patients.

METHODS

We conducted a multicenter, cross-sectional study. Cognitive function was assessed with the Mini-Mental State Examination (MMSE) score. Muscle strength was assessed by hand grip strength (HGS), muscle mass was assessed by lean tissue mass (LTM). Education status was divided into two groups: lower education status (senior middle school and below) and higher education status (high school and above). Multivariable logistic regression models and subgroup analyses were performed. Receiver-operating characteristic (ROC) analyses were conducted to compare their predictive power in discriminating CI.

RESULTS

2827 adult MHD patients were included in our final analysis. Patients in the lowest quartile of HGS was 2.82-fold as likely to have CI as compared to those in the highest quartile, while participants in the lowest quartile of LTM group were 1.52-fold as likely to have CI, when compared with the highest quartile group of LTM after adjusting for age, gender and education level. The association persisted in all subgroups except for women and well-educated participants. There was a significant interaction between HGS and education status on CI and age played an interactive role in the association between LTM and incident CI (P for interaction < 0.05). The AUC value of the HGS was significantly higher than that of LTM (0.69 VS 0.63, P < 0.001).

CONCLUSIONS

Muscle strength performed better than muscle mass in identifying individuals at high risk of CI, particularly in male and less educated Chinese MHD patients.

LEVEL OF EVIDENCE

Level V, cross-sectional study.

Sarcopenia and cardiovascular risk indices: Its impact on cardiovascular events and mortality in dialysis patients

BACKGROUND

Sarcopenia is a common complication in end-stage renal disease. Low muscle strength and muscle mass are risk factors for cardiovascular disease and mortality in patients undergoing dialysis. We studied the relation between sarcopenia and pre-atherosclerotic markers and its effect on cardiovascular events and death in dialysis patients.

METHODS

We measured muscle strength, muscle mass, carotid intima-media thickness, and pulse wave velocity in 106 patients. Sarcopenia was diagnosed according to the EWGSOP-2 suggestions. Patients with low muscle strength and low muscle mass were considered sarcopenic. The follow-up period for cardiovascular events and mortality was 24 months.

RESULTS

The mean age and dialysis duration were 57.4 ± 16.6 and 6.5 ± 4.9 years, respectively. Of all patients, 53 (50%) were male and 70 (66%) were on hemodialysis treatment. Sarcopenia and low muscle strength were seen in 47.1% and 88.7%, respectively. Hemodialysis patients were more likely to be sarcopenic than peritoneal dialysis patients (p = 0.001). Ferritin and Kt/V levels were higher, and body mass index was lower significantly in sarcopenic patients (p < 0.001). There was no significant difference in carotid intima-media thickness and pulse wave velocity measurements between the groups (p = 0.62 and p = 0.68, respectively). There was no statistically significant difference in cardiovascular events and mortality in cases with and without sarcopenia (p = 0.43 and p = 0.17, respectively).

CONCLUSION

There was no association between sarcopenia and pre-atherosclerotic markers, cardiovascular events, and all-cause mortality in dialysis patients. Techniques to detect low muscle strength and muscle mass need standardization, and new specific cut-off levels must be defined for dialysis patients.

Association of Physical Performance, Muscle Strength and Body Composition with Self-Assessed Quality of Life in Hemodialyzed Patients: A Cross-Sectional Study

(1) Patients on chronic hemodialysis (HD) experience impaired quality of life (QoL). We analyzed HD’s relationship with physical performance, body composition, and muscle strength; (2) QoL was assessed with the Short Form-36, composed of physical (PCS) and mental (MCS) health dimensions. Physical performance was assessed with the Short Physical Performance Battery (SPPB), body composition (lean tissue mass% (LTM%), fat tissue mass% (FTM%), and skeletal muscle mass% (SMM%)) was assessed with bioelectrical impedance, and lower extremity strength was assessed with a handheld dynamometer; and (3) we enrolled 76 patients (27 F, 49 M), age 62.26 ± 12.81 years, HD vintage 28.45 (8.65−77.49) months. Their QoL score was 53.57 (41.07−70.64); their PCS and MCS scores were 52.14 (38.69−65.95) and 63.39 (44.64−76.79) and strongly correlated (p < 0.0001, R = 0.738). QoL correlated positively with SPPB (R = 0.35, p ≤ 0.001), muscle strength (R from 0.21 to 0.41, p < 0.05), and LTM% (R = 0.38, p < 0.001) and negatively with FTM% (R = −0.32, p = 0.006). PCS correlated positively with SPPB (R = 0.42 p < 0.001), muscle strength (R 0.25−0.44, p < 0.05), and LTM% (R = 0.32, p = 0.006) and negatively with FTM% (R = −0.25, p = 0.031). MCS correlated positively with SPPB (R = 0.23, p = 0.047), SMM% (R = 0.25; p = 0.003), and LTM% (R = 0.39, p < 0.001) and negatively with FTM% (R = −0.34; p = 0.003). QoL was unrelated to sex (p = 0.213), age (p = 0.157), HD vintage (p = 0.156), and BMI (p = 0.202); (4) Better physical performance, leaner body composition, and higher muscle strength are associated with better mental and physical QoL in HD.

Effect of Intradialytic Supine Ergometer Exercise on Hemodialysis Patients with Different Nutritional Status

OBJECTIVE

It is important for hemodialysis patients to exercise while their nutritional status is being monitored. This study aimed to examine the difference in physical exercise function and the effect of exercise intervention in hemodialysis patients who were divided into two groups (high-nutrition and low-nutrition groups) based on the serum albumin levels.

METHOD

A total of 26 outpatients (18 men and 8 women) undergoing hemodialysis (age: 66 ± 10 years) were included in this study. The patients' body composition data (weight, body mass index, percentage of body fat, fat-free mass, and total body water) and physical functions (grip strength, knee extensor strength, open-eyed one-legged standing time, long sitting trunk anteflexion, and 6-minute walking distance [6MWD] test) were measured. The intervention was supine ergometer exercise during hemodialysis, and the patients exercised for 30 minutes during hemodialysis thrice a week. The intervention period was three months.

RESULTS

Compared to the high-nutrition group, the low-nutrition group showed a significant decrease in muscle strength. Furthermore, long sitting trunk anteflexion in the high-nutrition group and 6MWD in the low-nutrition group improved significantly after the intervention.

CONCLUSION

The result of this study may indicate that 6MD can be improved by exercise during dialysis, regardless of nutritional status. It is said that low nutritional status has a negative impact on survival rate; thus, considering the impact on survival rate, it is hemodialysis patients with a low nutritional status that should be considered to introduce more active exercise during dialysis.

Does the interference phenomenon affect strength development during same-session combined rehabilitation program in hemodialysis patients?

INTRODUCTION

This study aimed to assess if an interference effect could blunt the neuromuscular gains induced by a same-session combined rehabilitation in hemodialysis (HD) patients.

METHODS

Patients exercised twice a week, for 16 weeks, over their HD sessions. They were either always trained with resistance and endurance exercises (continuous training, "CONT") or alternatively with 1 week of resistance alternated with 1 week of endurance (discontinuous training, "DISC"). Adherence and workload were continuously recorded. Short Physical Performance Battery (SPPB) score, one-leg balance test, and handgrip and quadriceps strength were evaluated before and after training intervention.

RESULTS

Adherence to both programs was high (>90%). SPPB score had significantly improved (CONT: +1.5 point, DISC: +1.2 pt, p < 0.001), like one-leg balance test (CONT: +3.7 s, DISC: +5.5 s, p < 0.05), handgrip strength of exercised (CONT: +5.5 kg, DISC: +5.6 kg, p < 0.001) and of nonexercised arm (CONT: +4.4 kg, DISC: +2.8 kg, p < 0.01) as well as maximal quadriceps strength (+22 N·m for dominant and +29 N·m for nondominant leg in both groups, p < 0.001) bearing no difference between the trainings.

CONCLUSION

Same-session combined training does not induce an interference effect in HD patients and temporal separation of exercises does not optimize strength gains. These practical data may be relevant for clinicians and practitioners to alternate endurance and resistance exercises.

Longitudinal Assessment of Physical Activity, Fitness, Body Composition, Immunological Biomarkers, and Psychological Parameters During the First Year After Diagnosis in Women With Non-Metastatic Breast Cancer: The BEGYN Study Protocol

Background

Moderate physical activity is associated with an improved prognosis and psychosocial outcome in breast cancer patients. Although exercise and physical activity are associated with multiple physiological and psychological effects, many of the underlying mechanisms remain obscure. The BEGYN study (Influence of physical activity in breast cancer patients on physiological and psychological parameters and on biomarkers) aims at identifying potential associations between the extent of physical activity, fitness, body composition, immunological biomarkers, psycho-emotional parameters, and the course of treatment during the first year after diagnosis of breast cancer.

Methods

The prospective observational BEGYN study will include 110 non-metastatic breast cancer patients. The patients will be assessed during a base line visit prior to the initiation of the antineoplastic therapy and after 3, 6, 9 and 12 months. The physical activity will be measured using a fitness tracker and a self-assessment diary during the entire study. Each visit will include the assessment of (i) cardiorespiratory fitness measured by spiroergometry, (ii) body composition, (iii) psycho-emotional parameters (quality of life, mental health, fatigue, depression, distress, anxiety, well-being), and (iv) extensive blood tests including routine laboratory, vitamin D, selenium and immunologically relevant biomarkers (e.g., leukocyte subpopulations and cytokine profiles).

Discussion

Whereas most studies investigating the influence of physical activity in breast cancer patients focus on specific activities for three months or less, the BEGYN study will quantify the daily physical activity and cardiorespiratory fitness of breast cancer patients based on objective measurements in the context of the oncological therapy for 12 months after diagnosis. The study will reveal potential associations between exercise, immune status and physical as well as psycho-emotional outcome and the clinical course of the disease. Moreover, complementary therapies such as Vit D and Selenium supplementation and parameters investigating the motivation of the patients are part of the study. Due to this holistic approach, the BEGYN study will guide towards confirmatory studies on the role of physical activity in breast cancer patients to develop individualized counselling regarding the recommended type and extent of exercise.

Trial Registration

This study has been registered at the German Clinical Trials Register DRKS00024829.

Skeletal Muscle Phenotype in Patients Undergoing Long-Term Hemodialysis Awaiting Kidney Transplantation

BACKGROUND AND OBJECTIVES

Age and comorbidity-related sarcopenia represent a main cause of muscle dysfunction in patients on long-term hemodialysis. However, recent findings suggest muscle abnormalities that are not associated with sarcopenia. The aim of this study was to isolate functional and cellular muscle abnormalities independently of other major confounding factors, including malnutrition, age, comorbidity, or sedentary lifestyle, which are common in patients on maintenance hemodialysis. To overcome these confounding factors, alterations in skeletal muscle were analyzed in highly selected patients on long-term hemodialysis undergoing kidney transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In total, 22 patients on long-term hemodialysis scheduled for kidney transplantation with few comorbidities, but with a long-term uremic milieu exposure, and 22 age, sex, and physical activity level frequency-matched control participants were recruited. We compared biochemical, functional, and molecular characteristics of the skeletal muscle using maximal voluntary force and endurance of the quadriceps, 6-minute walking test, and muscle biopsy of vastus lateralis. For statistical analysis, mean comparison and multiple regression tests were used.

RESULTS

In patients on long-term hemodialysis, muscle endurance was lower, whereas maximal voluntary force was not significantly different. We observed a transition from type I (oxidative) to type II (glycolytic) muscle fibers, and an alteration of mitochondrial structure (swelling) without changes in DNA content, genome replication (peroxisome proliferator activator receptor γ coactivator-1α and mitochondrial transcription factor A), regulation of fusion (mitofusin and optic atrophy 1), or fission (dynamin-related protein 1). Notably, there were autophagosome structures containing glycogen along with mitochondrial debris, with a higher expression of light chain 3 (LC3) protein, indicating phagophore formation. This was associated with a greater conversion of LC3-I to LC3-II and the expression of Gabaralp1 and Bnip3l genes involved in mitophagy.

CONCLUSIONS

In this highly selected long-term hemodialysis population, a low oxidative phenotype could be defined by a poor endurance, a fiber-type switch, and an alteration of mitochondria structure, without evidence of sarcopenia. This phenotype could be related to uremia through the activation of autophagy/mitophagy.

CLINICAL TRIAL REGISTRATION NUMBERS

NCT02794142 and NCT02040363.

Creatinine index as a predictive marker of sarcopenia in patients under hemodialysis

PURPOSE

Sarcopenia is a clinical condition that comprises declined skeletal muscle (SM) mass and SM strength, and is a risk factor for physical disability, impaired quality of life, and advanced morbidity and mortality in patients on hemodialysis (HD). The existing difficulty in evaluating SM mass and consequently of sarcopenia, with affordable and practical methods in clinical practice, is well established. The purpose of this study is to examine the creatinine index (CrI), a surrogate of SM mass, as a potential predictive marker of sarcopenia.

METHODS

In this cross-sectional study, we included 130 patients on HD with a mean age of 66.17 ± 12.47 years. SM mass and SM strength were evaluated with CrI and hand grip strength, respectively. Anthropometric, adiposity, nutritional, and biochemical assessments were also performed. Partial correlation and multivariate regression analyses were applied to investigate the association between CrI and SM strength.

RESULTS

Correlation analysis showed that mid-arm circumference, calf circumference, Geriatric nutritional index, and albumin-to-total protein ratio were positively associated with SM strength. Multivariate model indicated that CrI (β = 2.05, p < 0.001) and dialysis duration (β =- 0.53, p = 0.001) were independently related to SM strength. The significant positive correlation between CrI and SM strength remained unaffected even after adjusting for potential confounders.

CONCLUSIONS

Creatinine Index was significantly associated with SM strength highlighting its value as a new emerging practical in clinical setting sarcopenia predictive marker in HD patients.

Dynapaenia and sarcopaenia in chronic haemodialysis patients: do muscle weakness and atrophy similarly influence poor outcome?

BACKGROUND

Sarcopaenia, defined as a decline in both muscle mass and function, has been recognized as a major determinant of poor outcome in haemodialysis (HD) patients. It is generally assumed that sarcopaenia is driven by muscle atrophy related to protein-energy wasting. However, dynapaenia, defined as weakness without atrophy, has been characterized by a different disease phenotype from sarcopaenia. The aim of this study was to compare the characteristics and prognosis of sarcopaenic and dynapaenic patients among a prospective cohort of chronic HD (CHD) patients.

METHODS

Two hundred and thirty-two CHD patients were enrolled from January to July 2016 and then followed prospectively until December 2018. At inclusion, weakness and atrophy were, respectively, evaluated by maximal voluntary force (MVF) and creatinine index (CI). Sarcopaenia was defined as the association of weakness and atrophy (MVF and CI below the median) while dynapaenia was defined as weakness not related to atrophy (MVF below the median, and CI above the median).

RESULTS

From a total of 187 prevalent CHD patients [65% of men, age 65.3 (49.7-82.0) years], 44 died during the follow-up period of 23.7 (12.4-34.9) months. Sarcopaenia and dynapaenia were observed in 33.7 and 16% of the patients, respectively. Compared with patients with sarcopaenia, patients with dynapaenia were younger and with a lower Charlson score. In contrast, mortality rate was similar in both groups (38 and 27%, respectively). After adjustment for age, sex, lean tissue index, serum albumin, high-sensitivity C-reactive protein (hs-CRP), haemoglobin (Hb), normalized protein catabolic rate (nPCR), dialysis vintage and Charlson score, only patients with dynapaenia were at increased risk of death [hazard ratio (HR) = 2.99, confidence interval 1.18-7.61; P = 0.02].

CONCLUSIONS

Screening for muscle functionality is highly warranted to identify patients with muscle functional impairment without muscle atrophy. In contrast to sarcopaenia, dynapaenia should appear as a phenotype induced by uraemic milieu, characterized by young patients with low Charlson score and poor prognosis outcome independently of serum albumin, hs-CRP, Hb, nPCR and dialysis vintage.

Snow removal maintained a high level of physical activity in patients undergoing hemodialysis in heavy snowfall areas

Background

Physical activity is an essential parameter associated with the prognosis of hemodialysis patients. Physical activity has regional characteristics; for example, snow removal is imperative in snowbelts during the winter. This study investigated the effects of removing snow on the physical activity levels of hemodialysis patients living in a snowbelt.

Methods

This study retrospectively examined 28 patients who underwent hemodialysis (age 69.6 ± 15.4 years, 19 males) in Uonuma Kikan Hospital between December 2019 and March 2020. Physical activity was assessed using the International Physical Activity Questionnaire. Patients were divided into a snow remover group and a non-snow remover group. We examined whether there were differences in physical or mental functioning and physical activity between the two groups. We also investigated the factors that influence high levels of physical activity among hemodialysis patients using multivariate linear regression analysis.

Results

The snow remover group had significantly greater grip strength, higher sit-to-stand test scores and gait speed, and a lower prevalence of frailty than the non-snow remover group. The level of physical activity was also significantly higher in the snow remover group. One of the patients in the snow remover group was frail. The univariate linear regression analysis showed that physical activity was related to age, grip strength, sit-to-stand test score, gait speed, and snow removal. In the multivariate linear regression analysis, snow removal and grip strength were significantly associated with a high level of physical activity.

Conclusions

Among hemodialysis patients living in a snowbelt, the snow remover group had significantly better physical functioning and a higher level of physical activity.

Uraemic toxins impair skeletal muscle regeneration by inhibiting myoblast proliferation, reducing myogenic differentiation, and promoting muscular fibrosis

Uraemic toxins increase in serum parallel to a decline in the glomerular filtration rate and the development of sarcopenia in patients with chronic kidney disease (CKD). This study analyses the role of uraemic toxins in sarcopenia at different stages of CKD, evaluating changes in the muscular regeneration process. Cultured C₂C₁₂ cells were incubated with a combination of indoxyl sulphate and p-cresol at high doses (100 µg/mL) or low doses (25 µg/mL and 10 µg/mL) resembling late or early CKD stages, respectively. Cell proliferation (analysed by scratch assays and flow cytometry) was inhibited only by high doses of uraemic toxins, which inactivated the cdc2-cyclin B complex, inhibiting mitosis and inducing apoptosis (analysed by annexin V staining). By contrast, low doses of uraemic toxins did not affect proliferation, but reduced myogenic differentiation, primed with 2% horse serum, by inhibiting myogenin expression and promoting fibro-adipogenic differentiation. Finally, to assess the in vivo relevance of these results, studies were performed in gastrocnemii from uraemic rats, which showed higher collagen expression and lower myosin heavy chain expression than those from healthy rats. In conclusion, uraemic toxins impair the skeletal muscular regeneration process, even at low concentrations, suggesting that sarcopenia can progress from the early stages of CKD.

Adherence and barriers to general and respiratory exercises in cystic fibrosis

OBJECTIVES

To investigate the adherence and the self-reported barriers to general and respiratory exercises reported by individuals with cystic fibrosis (CF).

STUDY DESIGN

An exploratory, experimental study.

METHODS

Community-dwelling individuals aged 16 years and over, diagnosed with CF, who were accompanied in referral centers were included. Information regarding adherence to exercises was obtained by a questionnaire and reported as a ratio between prescribed exercises and self-reported adherence. The weekly frequency was used to verify adherence to exercise initiation, and the amount of session duration concluded was used to verify adherence to exercise duration. Values above 0.70 were considered as high adherence. Eight demographic and clinical factors were examined to explore their relationships with adherence, and the barriers to exercises were also collected by questionnaire.

RESULTS

Thirty-four participants met the inclusion criteria. Overall, adherence to exercise initiation was 0.40 (standard deviation [SD] = 0.3) for general exercises and 0.63 (SD = 0.4) for respiratory exercises. Adherence to exercise duration was 0.76 (SD = 0.4) for general exercises and 0.73 (SD = 0.4) for respiratory exercises. Forced vital capacity (r = 0.39; P = .02) was associated with adherence to the duration of general exercises, and body mass index (r = -0.33; P = .05) was associated with adherence to the duration of respiratory exercises. The main reported barriers were lack of interest, motivation and time, tiredness, noncommitment, and do not recognize the benefits of exercises.

CONCLUSIONS

Individuals with CF minded completing the sessions of prescribed exercises once they have initiated it, but most of the days they did not practice general or respiratory exercises.

Quality of life of chronic kidney patients on hemodialysis and related factors

OBJECTIVE

to verify the association between the health-related quality of life of chronic renal patients on hemodialysis with sociodemographic, clinical, depression and medication adherence characteristics.

METHOD

a cross-sectional study with 183 chronic renal patients undergoing hemodialysis in the state of Rio Grande do Sul, Brazil. A sociodemographic and clinical questionnaire, Kidney Disease and Quality of Life Short-Form, Beck Depression Inventory and Morisky Medication Adherence Scale - eight items were used. Among the variables, comorbidities, complications of kidney disease and intercurrences during and after hemodialysis were evaluated. The analysis was performed with descriptive and analytical statistics.

RESULTS

55.2% of the patients were 60 years old or older, 35.0% were hypertensive, with regular quality of life, average of 62.61. Scores below average in the dimensions of quality of life were mainly associated with repetitive infections and edema as complications of the disease, pain during hemodialysis and weakness afterwards. Low drug adherence resulted in a worse quality of life, impacting ten of the 20 dimensions evaluated and depression in all, except for patient satisfaction.

CONCLUSION

reduced quality of life in this population is associated with depressive symptoms, complications such as repetitive infections, pain and anemia, weakness after the dialysis session and low medication adherence. Actions aimed at changing these factors can promote well-being.

Effect of a pedometer-based walking intervention on body composition in patients with ESRD: a randomized controlled trial

BACKGROUND

A randomized trial of a pedometer-based intervention with weekly activity goals led to a modest increase in step count among dialysis patients. In a secondary analysis, we investigated the effect of this intervention on body composition.

METHODS

Sixty dialysis patients were randomized to standard care or a 6-month program consisting of 3 months of pedometers and weekly step count targets and 3 months of post-intervention follow-up. We obtained bioelectrical impedance spectroscopy (BIS) data on 54 of these patients (28 control, 26 intervention) and used linear mixed-modeling (adjusted for sex and dialysis modality) to estimate differences in change in total-body muscle mass (TBMM) adjusted for height2, fat mass (kg), and body mass index (BMI) (kg/m2) between control and intervention groups.

RESULTS

The median age of participants was 57.5 years (53-66), and 76% were men. At baseline, there was no significant difference between groups in age, BMI, race, or body composition, but there were more men in the intervention group. After 3 months, patients in the intervention group increased their average daily steps by 2414 (95% CI 1047, 3782) more than controls (p < 0.001), but there were no significant differences in body composition. However, at 6 months, participants in the intervention had a significantly greater increase from baseline in TBMM of 0.7 kg/m2 (95% CI 0.3, 1.13), decrease in fat mass (- 4.3 kg [95% CI -7.1, - 1.5]) and decrease in BMI (- 1.0 kg/m2 [95% CI -1.8, - 0.2]) relative to controls. In post-hoc analysis, each increase of 1000 steps from 0 to 3 months was associated with a 0.3 kg decrease in fat mass (95% CI 0.05, 0.5) from 0 to 6 months, but there was no dose-response relationship with TBMM/ht2 or BMI.

CONCLUSION

A pedometer-based intervention resulted in greater decreases in fat mass with relative preservation of muscle mass, leading to a greater decrease in BMI over time compared with patients not in the intervention. These differences were driven as much by worsening in the control group as by improvement in the intervention group. Step counts had a dose-response relationship with decrease in fat mass.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02623348). 02 December 2015.

Real-time shear wave ultrasound elastography: a new tool for the evaluation of diaphragm and limb muscle stiffness in critically ill patients

BACKGROUND

Muscle weakness following critical illness is the consequence of loss of muscle mass and alteration of muscle quality. It is associated with long-term disability. Ultrasonography is a reliable tool to quantify muscle mass, but studies that evaluate muscle quality at the critically ill bedside are lacking. Shear wave ultrasound elastography (SWE) provides spatial representation of soft tissue stiffness and measures of muscle quality. The reliability and reproducibility of SWE in critically ill patients has never been evaluated.

METHODS

Two operators tested in healthy controls and in critically ill patients the intra- and inter-operator reliability of the SWE using transversal and longitudinal views of the diaphragm and limb muscles. Reliability was calculated using the intra-class correlation coefficient and a bootstrap sampling method assessed their consistency.

RESULTS

We collected 560 images. Longitudinal views of the diaphragm (ICC 0.83 [0.50-0.94]), the biceps brachii (ICC 0.88 [0.67-0.96]) and the rectus femoris (ICC 0.76 [0.34-0.91]) were the most reliable views in a training set of healthy controls. Intra-class correlation coefficient for inter-operator reproducibility and intra-operator reliability was above 0.9 for all muscles in a validation set of healthy controls. In critically ill patients, inter-operator reproducibility and intra-operator 1 and 2 reliability ICCs were respectively 0.92 [0.71-0.98], 0.93 [0.82-0.98] and 0.92 [0.81-0.98] for the diaphragm; 0.96 [0.86-0.99], 0.98 [0.94-0.99] and 0.99 [0.96-1] for the biceps brachii and 0.91 [0.51-0.98], 0.97 [0.93-0.99] and 0.99 [0.97-1] for the rectus femoris. The probability to reach intra-class correlation coefficient greater than 0.8 in a 10,000 bootstrap sampling for inter-operator reproducibility was respectively 81%, 84% and 78% for the diaphragm, the biceps brachii and the rectus femoris respectively.

CONCLUSIONS

SWE is a reliable technique to evaluate limb muscles and the diaphragm in both healthy controls and in critically ill patients.

TRIAL REGISTRATION

The study was registered (ClinicalTrial NCT03550222).

Indices calculated by serum creatinine and cystatin C as predictors of liver damage, muscle strength and sarcopenia in liver disease

Serum creatinine (Cr)-based glomerular filtration rate (CrGFR) is overestimated in liver disease. The present study evaluated whether the difference in CrGFR and cystatin C (CysC) GFR (dGFR) is significant in liver disease. The Cr-to-CysC ratio and sarcopenia index (SI) have been reported to correlate with muscle volume. An estimated total body muscle mass with Cr, CysC and calculated body muscle mass (CBMM) has also been reported to correlate with muscle mass. The applicability of dGFR, SI and CBMM for liver disease were evaluated. A total of 313 patients with liver damage were evaluated for Child-Pugh score, albumin-bilirubin (ALBI) score, model for end-stage liver disease, fibrosis-4, Cr, CysC, Cr-based estimated GFR (CreGFR), CysCGFR and grip strength. Of the 313 patients, 199 were evaluated using cross-sectional computed tomography (CT) of the third lumbar vertebra to determine the skeletal muscle (SM) mass. dGFR, CBMM and SI were compared to liver damage, muscle strength and muscle mass. In the 313 patients, dGFR was correlated with age, ALBI and grip strength; CBMM was correlated with body mass index (BMI) and grip strength; and SI was correlated with BMI and grip strength. In patients evaluated with CT, the correlation coefficients for CBMM and SI with SM were 0.804 and 0.293, respectively. Thus, CBMM and SI were associated with sarcopenia. The relationship between dGFR and ALBI does not differ with different grades of CrGFR-based chronic kidney disease (CKD). dGFR is a marker of liver damage and muscle strength regardless of CKD. CBMM and SI are markers for sarcopenia in liver disease.

Three compartment bioimpedance spectroscopy in the nutritional assessment and the outcome of patients with advanced or end stage kidney disease: What have we learned so far?

Bioimpedance spectroscopy (BIS) is an easily applicable tool to assess body composition. The three compartment model BIS (3C BIS) conventionally expresses body composition as lean tissue index (LTI) (lean tissue mass [LTM]/height in meters squared) and fat tissue index (FTI) (adipose tissue mass/height in meters squared), and a virtual compartment reflecting fluid overload (FO). It has been studied extensively in relation to diagnosis and treatment guidance of fluid status disorders in patients with advanced‐stage or end‐stage renal disease. It is the aim of this article to provide a narrative review on the relevance of 3C BIS in the nutritional assessment in this population. At a population level, LTI decreases after the start of hemodialysis, whereas FTI increases. LTI below the 10th percentile is a consistent predictor of outcome whereas a low FTI is predominantly associated with outcome when combined with a low LTI. Recent research also showed the connection between low LTI, inflammation, and FO, which are cumulatively associated with an increased mortality risk. However, studies toward nutritional interventions based on BIS data are still lacking in this population. In conclusion, 3C BIS, by disentangling the components of body mass index, has contributed to our understanding of the relevance of abnormalities in different body compartments in chronic kidney disease patients, and appears to be a valuable prognostic tool, at least at a population level. Studies assessing the effect of BIS guided nutritional intervention could further support its use in the daily clinical care for renal patients.

Associations between the measures of physical function, risk of falls and the quality of life in haemodialysis patients: a cross-sectional study

BACKGROUND

Impaired physical function due to muscle weakness and exercise intolerance reduces the ability to perform activities of daily living in patients with end-stage kidney disease, and by consequence, Health-Related Quality of Life (HRQoL). Furthermore, the risk of falls is an aggregate of physical function and, therefore, could be associated with HRQoL as well. The present study examined the associations between objective and subjective measures of physical function, risk of falls and HRQoL in haemodialysis patients.

METHODS

This cross-sectional multicentre study included patients on maintenance haemodialysis. Physical function (quadriceps force, handgrip force, Sit-to-Stand, and six-minute walking test), the risk of falls (Tinetti, FICSIT-4, and dialysis fall index) and HRQoL (PROMIS-29 and EQ-5D-3 L) were measured and analysed descriptively, by general linear models and logistic regression.

RESULTS

Of the 113 haemodialysis patients (mean age 67.5 ± 16.1, 57.5% male) enrolled, a majority had impaired quadriceps force (86.7%) and six-minute walking test (92%), and an increased risk of falls (73.5%). Whereas muscle strength and exercise capacity were associated with global HRQoL (R² = 0.32) and the risk of falls, the risk of falls itself was related to psycho-social domains (R² = 0.11) such as depression and social participation, rather than to the physical domains of HRQoL. Objective measures of physical function were not associated with subjective fatigue, nor with subjective appreciation of health status.

CONCLUSIONS

More than muscle strength, lack of coordination and balance as witnessed by the risk of falls contribute to social isolation and HRQoL of haemodialysis patients. Mental fatigue was less common than expected, whereas, subjective and objective physical function were decreased.

Effects of intradialytic aerobic exercise on hemodialysis patients: a systematic review and meta-analysis

OBJECTIVE

Intradialytic exercise (IDE) is not yet a routine practice for hemodialysis patients, the lack of guidelines supporting it being a major reason. This systematic review and meta-analysis of aerobic IDE interventions examined the efficacy of IDE regarding quality of life (QOL), serum phosphorus, dialysis efficiency, inflammatory status, vitamin D3, parathyroid hormone, intake of phosphate binders, mortality and hospitalization rate.

METHODS

Pubmed, Medline (Ovid), Embase (Ovid), Cochrane, and Cinahl (EBSCO) databases were searched to retrieve studies up to June 12, 2018. A manual reference search was also performed. Studies were included if they evaluated (a) aerobic IDE effect on at least one of our study parameters, (b) adult hemodialysis patients, (c) patients for > 1 month.

RESULTS

Twenty-two studies were retrieved (706 participants), of which 12 were eligible for meta-analysis. Aerobic IDE had a significant positive effect on the QOL physical component score (QOL-PSC) and on mental component score (QOL-MCS) of SF36, but not on serum phosphorus or Kt/V.

CONCLUSIONS

IDE incorporation into clinical practice has a significant positive effect on QOL-PSC and QOL-MCS. In the reviewed studies, IDE did not result in any health hazard in hemodialysis patients. Nevertheless, future research should assess the long-term effectiveness and safety of IDE. The limitations of this review include the lack of quality analysis of the studies, the limited number of studies that could be included in the meta-analysis, the diversity in the exercise intensity, duration and modality, and the limited data for several outcomes.

PROSPERO REGISTRATION ID

CRD42016052062.