Screening for muscle wasting and dysfunction in patients with chronic kidney disease

Seven months of aerobic intradialytic exercise training can prevent muscle loss in haemodialysis patients: an ultrasonography study

PURPOSE

This study aimed to evaluate the effects of 7-month intradialytic exercise training (IDE) on vastus lateralis (VL) muscle architecture, functional capacity and quality of life in stable haemodialysis (HD) patients.

METHODS

44 HD patients were randomly assigned into an Exercise Group (EG = 21), which they received 7 months of IET, at 60% of pre-assessed maximum aerobic power, 3/week) or into a Control Group (CG = 23, no exercise). VL architecture was evaluated with ultrasonography, functional capacity was assessed using a series of functional tests (6 min walking test, 5 repetitions sit-to-stand, sit-to-stand 60 s, handgrip strength), and maximal aerobic power determined with a modified version of the Åstrand test. Quality of life and fatigue levels were evaluated using validated questionnaires.

RESULTS

VL fascicle angle and length did not change significantly in both groups (P > 0.05). Muscle thickness decreased in CG (P = 0.02) while it was fully preserved in the EG. Functional capacity increased only in the EG (6 min walking test 15.79 ± 12.35%, P < 0.001; max aerobic power 26.36 ± 1.24%, P < 0.001; STS-60rep: 10.23 ± 1.60%, P < 0.000; hand grip strength: 5.14 ± 28.30%, P < 0.02).

CONCLUSION

Intradialytic aerobic exercise training, improves functional capacity and prevents thigh muscle mass loss in HD patients. It is evident that muscle ultrasonography could play a pivotal role in assessing muscle quality changes in haemodialysis patients. A higher level of training intensity or combination with resistance exercises may be required to further improve anabolism and influence muscle architecture in this patient population.

CLINICAL TRIAL REGISTRY NUMBER

NCT03905551.

Association analysis of body composition with survival among prevalent peritoneal dialysis patients

PURPOSE

Progressive decline in lean mass and gain of fat mass are common in patients treated with peritoneal dialysis (PD). It is unclear whether body composition or its longitudinal changes contribute to increased mortality among prevalent PD patients.

METHODS

This was a retrospective cohort study. Body composition was assessed using bioelectrical impedance spectroscopy (BIS). Lean and fat tissue indices were derived from lean and fat mass indexed to height-squared, respectively. The patient's baseline BIS results were used to explore its mortality risk prediction for the entire cohort. Among patients with subsequent BIS measurements, changes of lean and fat mass over time were also examined with survival outcomes.

RESULTS

Among all participants (n = 555, PD vintage 38 months), higher baseline lean tissue index was associated with lower mortality after adjusting for fat tissue index and confounders (HR 0.90; 95% CI 0.84-0.97, p = 0.01). However, this association was no longer significance after the final adjustment with serum albumin level (p = 0.06). A total of 136 patients had repeated BIS data. After the interval of 10.1 months during two consecutive BIS measurements, there was a strong inverse correlation between the percentage changes of lean and fat tissue indices (r = - 0.73, p < 0.001). The longitudinal changes in lean mass, either high or low categories, were not significantly associated with all-cause mortality. In contrast, patients who were classified as having low values of fat tissue index (below median) from baseline to the next BIS measurements had a lower odds of death in the univariable (HR 0.32; 95% CI 0.12-0.84, p = 0.02) but not in the adjusted models.

CONCLUSION

Among prevalent PD patients, higher baseline lean mass was independently associated with better survival. However, the longitudinal changes in lean mass were not significantly associated with mortality. In contrast, the maintenance of low fat status over time appeared to be associated with a lower likelihood of death among PD population.

Application of Magnetic Resonance Imaging in the Evaluation of Nutritional Status: A Literature Review with Focus on Dialysis Patients

Magnetic resonance imaging (MRI) is indispensable in clinical medicine for the morphological and tomographic evaluation of many parenchymal organs. With varied imaging methods, diverse biological information, such as the perfusion volume and measurements of metabolic products, can be obtained. In addition to conventional MRI for morphological assessment, diffusion-weighted MRI/diffusion tensor imaging is used to evaluate white matter structures in the brain; arterial spin labeling is used for cerebral blood flow evaluation; magnetic resonance elastography for fatty liver and cirrhosis evaluation; magnetic resonance spectroscopy for evaluation of metabolites in specific regions of the brain; and blood oxygenation level-dependent imaging for neurological exploration of eating behavior, obesity, and food perception. This range of applications will continue to expand in the future. Nutritional science is a multidisciplinary and all-inclusive field of research; therefore, there are many different applications of MRI. We present a literature review of MRI techniques that can be used to evaluate the nutritional status, particularly in patients on dialysis. We used MEDLINE as the information source, conducted a keyword search in PubMed, and found that, as a nutritional evaluation method, MRI has been used frequently to comprehensively and quantitatively evaluate muscle mass for the determination of body composition.

Using the theoretical domains framework to inform strategies to support dietitians undertaking body composition assessments in routine clinical care

BACKGROUND

Malnutrition, sarcopenia and cachexia are clinical wasting syndromes characterised by muscle loss. Systematic monitoring by body composition assessment (BCA) is recommended for the diagnosis, treatment and monitoring of the syndrome(s). This study investigated practices, competency, and attitudes of Australian dietitians regarding BCA, to inform a local implementation process.

METHODS

Applying the Action cycle in the Knowledge to Action framework, surveys were distributed to the 26 dietitians of an 800-bed tertiary hospital. The survey assessed barriers and enablers to performing routine BCA in clinical care. Results were categorised using the Theoretical Domains Framework (TDF) and suitable interventions mapped using the Behaviour Change Wheel.

RESULTS

Twenty-two dietitians (84.6%) completed the survey. Barriers to BCA were identified in all TDF domains, particularly in Knowledge, Skills, Social/professional role and identity, Beliefs about capabilities, and Environmental context and resources. Enablers existed in domains of: Skills; Beliefs about consequences; Goals; Environmental context and resources; Social influences; Intentions; Optimism; Reinforcement.

CONCLUSIONS

This study showed that hospital dietitians experience individual, team, and organisational barriers to adopt BCAs in clinical practice. We were able to formulate targeted implementation strategies to overcome these barriers to assist BCA adoption into routine practice.

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

Background

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

Methods

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

Results

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

Conclusion

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

Evolution of body composition and wasting indicators by time of day of haemodialysis

BACKGROUND

It has been a long-standing clinical concern that haemodialysis (HD) patients on afternoon shifts (ASs) are more prone to protein-energy wasting (PEW) than those on morning shifts (MSs), as their dialysis scheme and post-dialysis symptoms may interfere with meal intake. We evaluated the effect of time of day of HD on the evolution of body composition changes and PEW surrogates.

METHODS

We conducted a retrospective study among 9.963 incident HD patients treated in NephroCare centres (2011-16); data were routinely collected in the European Clinical Database. The course of multi-frequency bioimpedance determined lean and fat tissue indices (LTI and FTI) between patients in MSs/ASs over 2 years were compared with linear mixed models. Secondary PEW indicators were body mass index, albumin, creatinine index and normalized protein catabolic rate. Models included fixed (age, sex, vascular access and diabetes mellitus) and random effects (country and patient).

RESULTS

Mean baseline LTI and FTI were comparable between MSs (LTI: 12.5 ± 2.9 kg/m2 and FTI: 13.7 ± 6.0 kg/m2) and ASs (LTI: 12.4 ± 2.9 kg/m2 and FTI: 13.2 ± 6.1 kg/m2). During follow-up, LTI decreased and FTI increased similarly, with a mean absolute change (baseline to 24 months) of -0.3 kg/m2 for LTI and +1.0 kg/m2 for FTI. The course of these malnutrition indicators did not differ between dialysis shifts (P for interaction ≥0.10). We also did not observe differences between groups for secondary PEW indicators.

CONCLUSIONS

This study suggests that a dialysis shift in the morning or in the afternoon does not impact the long-term nutritional status of HD patients. Regardless of time of day of HD, patients progressively lose muscle mass and increase body fat.

Quantitative Muscle Ultrasonography Using 2D Textural Analysis: A Novel Approach to Assess Skeletal Muscle Structure and Quality in Chronic Kidney Disease

Chronic kidney disease (CKD) is characterized by progressive reductions in skeletal muscle function and size. The concept of muscle quality is increasingly being used to assess muscle health, although the best means of assessment remains unidentified. The use of muscle echogenicity is limited by an inability to be compared across devices. Gray level of co-occurrence matrix (GLCM), a form of image texture analysis, may provide a measure of muscle quality, robust to scanner settings. This study aimed to identify GLCM values from skeletal muscle images in CKD and investigate their association with physical performance and strength (a surrogate of muscle function). Transverse images of the rectus femoris muscle were obtained using B-mode 2D ultrasound imaging. Texture analysis (GLCM) was performed using ImageJ. Five different GLCM features were quantified: energy or angular second moment (ASM), entropy, homogeneity, or inverse difference moment (IDM), correlation, and contrast. Physical function and strength were assessed using tests of handgrip strength, sit to stand-60, gait speed, incremental shuttle walk test, and timed up-and-go. Correlation coefficients between GLCM indices were compared to each objective functional measure. A total of 90 CKD patients (age 64.6 (10.9) years, 44% male, eGFR 33.8 (15.7) mL/minutes/1.73 m2) were included. Better muscle function was largely associated with those values suggestive of greater image texture homogeneity (i.e., greater ASM, correlation, and IDM, lower entropy and contrast). Entropy showed the greatest association across all the functional assessments (r = -.177). All GLCM parameters, a form of higher-order texture analysis, were associated with muscle function, although the largest association as seen with image entropy. Image homogeneity likely indicates lower muscle infiltration of fat and fibrosis. Texture analysis may provide a novel indicator of muscle quality that is robust to changes in scanner settings. Further research is needed to substantiate our findings.

Short-term intradialytic NMES targeting muscles of the legs improves the phase angle: A pilot randomized clinical trial

PURPOSE

Neuromuscular electrical stimulation (NMES) elicits muscle contraction and has been shown to attenuate muscle atrophy when physical activity is not possible. Thus, we hypothesized that intradialytic NMES would attenuate the loss leg lean mass and improve the phase angle in patients undergoing hemodialysis (HD).

METHODS

A randomized controlled trial was performed with twenty-one adult HD patients (n = 8 F, n = 13 M; 45.8 ± 10.6 y) randomly assigned to usual care (control group, n = 11; 4F/7M) or to the NMES group (n = 10; 4F/6M). NMES was applied bilaterally at the origin and insertion points of the quadriceps or gastrocnemius muscles for 40 min during each HD session (3x/wk for one month). Pre-and post-intervention, we measured leg lean mass using dual-energy x-ray absorptiometry and phase angle using bioelectrical impedance analysis.

RESULTS

NMES did not change leg lean mass compared to the control group. Phase angle increased in the NMES compared to the control group (Δ: +0.71 ± 0.27° vs. -0.46 ± 0.23°, p = 0.004) with interaction time x treatment (ANOVA p = 0.004).

CONCLUSION

Short-term intradialytic NMES targeting muscles of the legs improved the phase angle but did not change leg lean mass.

BRAZILIAN REGISTRY OF CLINICAL TRIALS UNDER THE CODE

RBR-98wzgn.

Ultrasound for Non-invasive Assessment and Monitoring of Quadriceps Muscle Thickness in Critically Ill Patients With Acute Kidney Injury

Background and aims: Critically ill patients with acute kidney injury (AKI) undergo major muscle wasting in the first few days of ICU stay. An important concern in this clinical setting is the lack of adequate tools for routine bedside evaluation of the skeletal muscle mass, both for the determination of nutritional status at admission, and for monitoring. In this regard, the present study aims to ascertain if ultrasound (US) is able to detect changes in quadriceps muscle thickness of critically ill patients with acute kidney injury (AKI) over short periods of time. Methods: This is a prospective observational study with a follow-up at 5 days. All adult patients with AKI hospitalized at the Renal ICU of the Parma University Hospital over 12 months, with a hospital stay before ICU admission no longer than 72 h, and with a planned ICU stay of at least 5 days, were eligible for the study. An experienced investigator assessed quadriceps rectus femoris and vastus intermedius thickness (QRFT and QVIT) at baseline and after 5 days of ICU stay. Results: We enrolled 30 patients with 74 ± 11 years of age and APACHE II score of 22 ± 5. Muscle thickness decreased by 15 ± 13% within the first 5 days of ICU stay (P < 0.001 for all sites as compared to ICU admission). Patients with more severe muscle loss had lower probability of being discharged home (OR: 0.04, 95%CI: 0.00-0.74; P = 0.031). Conclusions: In critically ill patients with AKI, bedside muscle US identifies patients with accelerated muscle wasting.

Accelerated decline in quadriceps area and Timed Up and Go test performance are associated with hip fracture risk in older adults with impaired kidney function

OBJECTIVE

This study aimed to examine whether an accelerated decline in quadriceps cross-sectional area (CSA), attenuation (a surrogate of quality), and strength, as well as lower limb muscular function, are associated with hip fractures in older adults with impaired kidney function.

DESIGN

Prospective population-based study.

SETTING

Community-dwelling old population in Reykjavik, Iceland.

SUBJECTS

A total of 875 older adults (mean baseline age 76 years) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study with impaired kidney function.

METHODS

Quadriceps CSA and density were determined using computed tomography (CT), knee extension strength was measured with an isometric dynamometer chair, and muscular function was assessed using the Timed Up and Go (TUG) test. All muscle-related measurements were assessed twice over a mean follow-up of 5.2 years. Data on hip fracture incidence was obtained from medical records during a maximum of 8.4 years of follow-up time.

RESULTS

Fully adjusted cox-proportional hazard regression models showed that a faster decline in quadriceps CSA and TUG test performance were significantly associated with increased hip fracture risk (HR = 1.55, 95% CI = 1.02-2.36, and HR = 1.80, 95% CI = 1.19-2.72, respectively). A faster decrease in quadriceps density and isometric knee extension strength were not associated with fracture risk.

CONCLUSIONS

Accelerated decline in CT-derived quadriceps CSA and muscular function, as measured by the TUG test's performance, are predictive of hip fracture risk in older adults with impaired kidney function. TUG test is a simple measure and easily included in routine medical examinations, compared to CT scans, which seems to be useful for identifying a subgroup of individuals with high risk of fracture.

Clinical and predictive value of simplified creatinine index used as muscle mass surrogate in end-stage kidney disease haemodialysis patients-results from the international MONitoring Dialysis Outcome initiative

Background

Protein-energy wasting, muscle mass (MM) loss and sarcopenia are highly prevalent and associated with poor outcome in haemodialysis (HD) patients. Monitoring of MM and/or muscle metabolism in HD patients is of paramount importance for timely detection of muscle loss and to intervene adequately. In this study we assessed the reliability and reproducibility of a simplified creatinine index (SCI) as a surrogate marker of MM and explored its predictive value on outcome.

Method

We included all in-centre HD patients from 16 European countries with at least one SCI. The baseline period was defined as 30 days before and after the first multifrequency bioimpedance spectroscopy measurement; the subsequent 7 years constituted the follow-up. SCI was calculated by the Canaud equation. Multivariate Cox proportional hazards models were applied to assess the association of SCI with all-cause mortality. Using backward analysis, we explored the trends of SCI before death. Bland–Altman analysis was performed to analyse the agreement between estimated and measured MM.

Results

We included 23 495 HD patients; 3662 were incident. Females and older patients have lower baseline SCI. Higher SCI was associated with a lower risk of mortality [hazard ratio 0.81 (95% confidence interval 0.79–0.82)]. SCI decline accelerated ∼5–7 months before death. Lean tissue index (LTI) estimated by SCI was correlated with measured LTI in both sexes (males: R² = 0.94; females: R² = 0.92; both P < 0.001). Bland–Altman analysis showed that measured LTI was 4.71 kg/m² (±2 SD: −12.54–3.12) lower than estimated LTI.

Conclusion

SCI is a simple, easily obtainable and clinically relevant surrogate marker of MM in HD patients.

Frequency of Intradialytic Hypotension Events Do Not Increase with Oral Nutritional Supplementation during Hemodialysis Treatment: A Randomized Controlled Trial

OBJECTIVE

This study aimed to compare the effect of the use of a renal-specific oral nutritional supplement (RS-ONS) during hemodialysis sessions and the use of RS-ONS at home on the incidence of intradialytic hypotension.

METHODS

A single-center, 12-week, open-label, randomized controlled clinical trial was conducted. The intervention was a RN-ONS divided into two portions: 100 and 137 mL. The first portion was given after 1 hour of hemodialysis (HD) treatment, while the second portion was given 45 minutes before the end of HD. The research staff registered the baseline and final nutritional parameters and systolic arterial pressure (SAP) from the screen of the HD device during 36 HD sessions. Hypotension symptoms were also recorded every hour during each HD session. The nutritional and functional status was also assessed.

RESULTS

We registered a total of 16 hypotensive events during 1082 HD sessions: 9 were in patients supplemented at home (551 HD sessions) and 7 occurred in patients supplemented during HD P = .668. Incidence of intradialytic hypotension (IH) during 1082 HD sessions was 1.4%. The total malnutrition inflammation score (MIS) decreased in both groups (P < .01), and the percentage of cachexia improved in the supplemented-during-HD group (P < .05).

CONCLUSIONS

In this randomized controlled trial, intradialytic hypotension events did not increase with the RS-ONS during HD treatment. This strategy appears to be a safe anabolic nutritional strategy for the prevention of PEW, selecting stable patients and administering a fractioned volume of the supplement after the first hour of HD treatment. More studies with larger samples size are required to confirm these findings.

Protein-Energy Wasting and Mortality Risk Prediction Among Peritoneal Dialysis Patients

OBJECTIVES

Protein-energy wasting (PEW) is defined as the loss of body protein and energy reserves associated with kidney disease. However, the extent to which PEW contributes to increased mortality among peritoneal dialysis (PD) patients remains unclear.

METHODS

This is a retrospective cohort study from 2012 to 2020. The PEW was diagnosed by applying at least 3 of the 4 following criteria: (1) altered serum biochemistry indicated by a serum albumin level of <3.5 g/L; (2) decreased body mass status identified by a body mass index (BMI) of <23 kg/m² or <10% total body fat; (3) muscle wasting defined by the lean tissue index, calculated as a lean tissue mass normalized to the height-squared in the <10th percentile of the reference population; and (4) low dietary protein intake determined by the normalized protein equivalent of a total nitrogen appearance of <0.8 g/kg/day. The Malnutrition Inflammation Score (MIS) was also examined as an alternative tool for assessment of PEW.

RESULTS

The average age of the 555 participants was 57.5 ± 12.6 years. The prevalence of PEW was 27.3%, with 196 deaths observed during the mean follow-up of 25.5 months. Patients with PEW who fulfilled at least 3 of the 4 listed criteria had a higher risk of death in the unadjusted model (hazard ratio 1.61, 95% confidence interval 1.19-2.18, P = .002). However, these associations were attenuated after adjusting for potential confounders. Regarding the individual PEW criterion, decreased serum albumin and low muscle mass were significantly associated with mortality in the multivariable models. In contrast, decreased body mass and low protein intake were not associated with a higher risk of death. High MIS (≥5 points) and each one-point increase in the MIS were also significantly associated with higher risk of death in both unadjusted and adjusted models.

CONCLUSIONS

Among PD patients, the presence of PEW was not a better predictor of all-cause mortality than either the altered serum biochemistry (albumin) or low muscle mass criteria. The MIS performed well as an independent predictor of death and might be an option for assessment of PEW status in the PD population.

Utility of Ultrasound as a Valid and Accurate Diagnostic Tool for Sarcopenia: Sex-Specific Cutoff Values in Chronic Kidney Disease

OBJECTIVES

Patients with chronic kidney disease (CKD) have aberrant changes in body composition, including low skeletal muscle mass, a feature of "sarcopenia." The measurement of the (quadriceps) rectus femoris (RF) cross-sectional area (CSA) is widely used as a marker of muscle size. Cutoff values are needed to help discriminate the condition of an individual's muscle (eg, presence of sarcopenia) quickly and accurately. This could help distinguish those at greater risk and aid in targeted treatment programs.

METHODS

Transverse images of the RF were obtained by B-mode 2-dimensional ultrasound imaging. Sarcopenic levels of muscle mass were defined by established criteria (1, appendicular skeletal muscle mass [ASM]; 2, ASM/height² ; and 3, ASM/body mass index) based on the ASM and total muscle mass measured by a bioelectrical impedance analysis. The discriminative power of RF-CSA was assessed by receiver operating characteristic curves, and optimal cutoffs were determined by the maximum Youden index (J).

RESULTS

One hundred thirteen patients with CKD (mean age [SD], 62.0 [14.1] years; 48% male; estimated glomerular filtration rate, 38.0 [21.5] mL/min/1.73m² ) were included. The RF-CSA was a moderate predictor of ASM (R² = 0.426; P < .001) and total muscle mass (R² = 0.438; P < .001). With a maximum J of 0.47, in male patients, an RF-CSA cutoff of less than 8.9 cm² was deemed an appropriate cutoff for detecting sarcopenic muscle mass. In female patients, an RF-CSA cutoff of less than 5.7 cm² was calculated on the basis of ASM/height² (J = 0.71).

CONCLUSIONS

Ultrasound may provide a low-cost and simple means to diagnose sarcopenia in patients with CKD. This would allow for early management and timely intervention to help mitigate the effects in this group.

Is peritoneal dialysis suitable technique CKD patients over 65 years? A prospective multicenter study

BACKGROUND

Chronic kidney disease (CKD) is increasing in patients older than 65years and is related to morbidity, frailty, and dependence. Peritoneal dialysis (PD) has classically been associated with young patients with an active life.

HYPOTHESIS

PD should be offered to patients over 65years. We search for any unfavorable results that may advice not to recommend PD therapy for this group.

OBJECTIVE

To describe PD treatment and outcomes in patients >65years, to compare their results with patients <65years and to identify areas with room for improvement in a real-life study.

STUDY

Prospective, observational, and multicenter study performed in incident PD patients, from January 2003 until January 2018.

RESULTS

We included 2,435 PD patients, 31.9% were older than 65years; there was a difference of 25years between both groups. Median follow up was 2.1years. Older than 65years group had more comorbidity: Diabetes (29.5% vs 17.2%; p<0.001), previous CV events 34.5% vs 14.0%; p<0.001), Charlson index (3.8 vs 3.0; p<0.001). We did not find differences in efficacy and PD adequacy objectives fulfillment, anaemia management or blood pressure during follow-up. Peritonitis rate was higher in older 65years group (0.65 vs 0.45 episodes/patient/year; p<0.001), but there was not differences in germs, admission rate and follow up. Mortality was higher in older 65years group (28.4% vs 9.4%) as expected. PD permanence probability was similar (2.1years). The main cause of PD withdrawal was transplant in group <65years (48.3%) and transfer to HD in group >65years. The main reason was caregiver or patient fatigue (20.2%), and not technique failure (7.3%). Multivariate Cox regression analysis showed a relation (HR [95%CI]) between mortality and age>65years 2.4 [1.9-3.0]; DM 1.6 [1.3-2.1]; CV events 2.1 [1.7-2.7]. Multivariate Cox regression analysis identify a relation between technique failure and age>65years 1.5 [1.3-1.9]; DM 1.6 [1.3-1.9] and previous transplant 1.5 [1.2-2.0].

CONCLUSION

Patients older than 65years fulfilled PD adequacy criteria during the follow up. We believe PD is a valid option for patients older 65years. It is necessary to try to prevent infections and patient/caregiver fatigue, to avoid HD transfer for reasons not related to technique failure.

Establishing Reference Values for Lean Muscle Mass in the Pediatric Patient

OBJECTIVES

Adults with decreased muscle mass experience worse outcomes and more frequent complications. The effects of sarcopenia on pediatric outcomes are unknown. Our objective was to define reference values for lean muscle mass in a healthy pediatric population to facilitate future studies on the impact of lean muscle mass on pediatric outcomes.

PATIENTS AND METHODS

Bilateral psoas muscle surface area was measured by computed tomography in a healthy pediatric population undergoing evaluation after trauma. Pearson correlation coefficients (PCCs) were calculated for age, weight, height, body mass index (BMI), total psoas muscle area, and psoas muscle index (PMI; defined as psoas muscle area divided by height squared). Quantile regression was used to determine age- and sex-specific percentiles of psoas muscle area and PMI.

RESULTS

Analysis of 494 male and 288 female patients with available imaging (median age: 9.3 years, interquartile range: 5.4-13.4; 63.1% male) was performed. For males, age correlated strongly with total psoas volume (PCC = 0.87), height (0.95), and weight (0.88) and poorly with BMI (0.45). In females, age correlated strongly with total psoas volume (0.88), height (0.92), weight (0.88) and poorly with BMI (0.19). Gender-specific curves and charts were created using output from the quantile regression from reference values of the total psoas muscle area corresponding to the 25th, 50th, and 75th percentiles across all ages.

CONCLUSIONS

We created gender-specific reference charts for total and height-normalized psoas muscle area in healthy children based on age. These results can be used in future studies to establish the effects of sarcopenia in pediatric patients.

QT Prolongation in Dialysis Patients: An Epidemiological Study with a Focus on Malnutrition

BACKGROUND/AIMS

QT prolongation is a known risk factor for ventricular fibrillation and ventricular tachycardia. Therefore, more refined management is necessary to reduce sudden cardiac death secondary to such arrhythmias.

METHODS

Electrocardiographic findings were reviewed in 224 patients, and the associations of QT prolongation with various clinical parameters were examined, including the nutritional state. Correlations were also examined between QT prolongation and body composition measurements determined by multifrequency bioelectrical impedance analysis.

RESULTS

Prolongation of the corrected QT (QTc) interval over 0.44 s was seen in 140 patients (62.5%). QT prolongation was independent of age and dialysis therapy duration and was more frequent in diabetics (70.1%) than in nondiabetics (54.2%, p = 0.014) and more frequent in women (78.8%) than in men (53.5%, p < 0.001). Serum levels of albumin (p < 0.001) and Cr (p < 0.001) and the Geriatric Nutritional Risk Index (GNRI, p < 0.001) were negatively correlated with QTc interval; no significant correlation was noted with total protein, urea nitrogen, or uric acid. Negative correlations with QTc interval were found for BMI(p < 0.01), percent total body water (%TBW; p < 0.05), and percent intracellular water (%ICW; p < 0.01) but not with the percent extracellular water/TBW ratio or edema ratio. The longer the QTc interval, the lower the fat-free mass (FFM; p < 0.01) and muscle mass (MM; p < 0.01), but there was no significant correlation with percent fat.

CONCLUSION

These results suggest that QT prolongation is a common complication and is more frequent in women and diabetic patients. The decreases in serum albumin and Cr levels, GNRI, BMI, %TBW, %ICW, FFM, and MM together coincided with malnutrition and thus suggest a close relationship of QT prolongation with malnutrition. Management of QT prolongation may be achieved better in the future by understanding these biochemical and biophysical changes, particularly those regarding malnutrition.

Physical Function in Kidney Transplantation: Current Knowledge and Future Directions

Purpose of review

Low physical function (PF) is common among individuals with end-stage kidney disease. In this review, we explore data on the impacts of PF on access to kidney transplantation (KT) and KT outcomes. We also discuss the latest interventions to improve PF in pre- and post-KT settings.

Recent Findings

Many US KT programs measure PF or related constructs when assessing KT candidacy. Although carefully selected KT candidates with low PF can benefit from KT with respect to survival and quality of life, low PF decreases the likelihood of being listed for KT and increases the risk of adverse post-KT outcomes. Recent trials suggest that exercise is a promising strategy to improve PF among KT candidates and recipients.

Summary

PF is a potentially modifiable risk factor for adverse pre- and post-KT outcomes. Research is needed to determine the ideal PF metric for use in KT evaluations and interventions to improve PF.

Preliminary Study of the Effects of Eccentric-Overload Resistance Exercise on Physical Function and Torque Capacity in Chronic Kidney Disease

The purpose of this preliminary study was to describe changes in physical function and torque capacity in adults with chronic kidney disease (CKD) in response to a novel progressive eccentric-overload resistance exercise (ERE) regime. Participants included men (n = 4) diagnosed with CKD according to estimated glomerular filtration rate (eGFR) between 59 and 15 mL/kg/1.73 m2 and not requiring dialysis. Physical function was determined by the Short Physical Performance Battery (SPPB), five repetitions of a sit-to-stand (STS) task, and timed-up and go (TUG). Knee extensor strength was assessed using both isometric and isokinetic contractions and performance fatigability indexes were calculated during a 30-s maximal isometric test and a 30-contraction isokinetic test at 180°/second. None of the patients exhibited significant worsening in their health status after training. Participants demonstrated improvements in several measures of physical function and torque capacity following 24 sessions of ERE. Following training, performance fatigability remained relatively stable despite the increases in torque capacity, indicating the potential for greater fatigue resistance. These findings provide initial evidence for ERE as a potential treatment option to combat declines in physical function and neuromuscular impairments in people with CKD. Future research is required to determine optimal progression strategies for maximizing specific neuromuscular and functional outcomes when using ERE in this patient population.

Sarcopenia predicts prognosis of patients with renal cell carcinoma: A systematic review and meta-analysis

Sarcopenia, a concept reflecting the loss of skeletal muscle mass, was reported to be associated with the prognosis of several tumors. However, the prognostic value of sarcopenia in patients with renal cancer remains unclear. We carried out this metaanalysis and systematic review to evaluate the prognostic value of sarcopenia in patients with renal cell carcinomas. We comprehensively searched PubMed, Embase, and Cochrane Library from inception to December 2018. Hazard ratio (HR) and 95% confidence interval (CI) were pooled together. A total of 5 studies consisting of 771 patients were enrolled in this quantitative analysis, 347 (45.0%) of which had sarcopenia. Patients with sarcopenia had a worse OS compared with those without sarcopenia (HR=1.76; 95%CI, 1.35-2.31; P <0.001). In the subgroup of patients with localized and advanced/metastatic diseases, sarcopenia was also associated with poor OS (HR=1.48, P=0.039; HR=2.14, P <0.001; respectively). With a limited sample size, we did not observe difference of PFS between two groups (HR=1.56, 95% CI, 0.69-3.50, P=0.282). In the present meta-analysis, we observed that patients with sarcopenia had a worse OS compared with those without sarcopenia in RCC. Larger, preferably prospective studies, are needed to confirm and update our findings.

Nonalcoholic fatty liver disease and sarcopenia: pathophysiological connections and therapeutic implications

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is currently one of the most common liver diseases worldwide. Recent data suggest that loss of skeletal muscle mass and function (i.e. sarcopenia) is highly prevalent and frequently overlooked in NAFLD patients. Experimental and clinical data suggest that the relationship between NAFLD and sarcopenia is pathophysiologically complex and bi-directional and there is a growing interest in unveiling how sarcopenia could influence NAFLD development and progression.

AREAS COVERED

PubMed/MEDLINE was searched for articles related to concomitant occurrence of NAFLD and sarcopenia between January 2013 and April 2020. Areas covered in this review include: (1) updated sarcopenia diagnosis strategy, (2) discussion of current data on pathophysiological connections between NAFLD and sarcopenia, and (3) analysis of current and future therapeutic implications of this knowledge.

EXPERT OPINION

Clinical studies describe a consistent association between NAFLD and sarcopenia, although a cause-effect relation remains to be determined. Active implementation of current diagnosis algorithms and optimized treatment can prevent sarcopenia related complications in subjects with NAFLD. Pathogenic pathways implicated in this relation are multiple and complex, a better understanding of them can provide novel biomarkers and targeted therapies that will hopefully have an important impact in NAFLD management.

Association of Ultrasound-Derived Metrics of the Quadriceps Muscle with Protein Energy Wasting in Hemodialysis Patients: A Multicenter Cross-Sectional Study

This study aimed to assess muscle wasting and risk of protein energy wasting (PEW) in hemodialysis (HD) patients using an ultrasound (US) imaging method. PEW was identified using the ISRNM criteria in 351 HD patients. Quadriceps muscle thickness of rectus femoris (RF) and vastus intermedius (VI) muscles and cross-sectional area (CSA) of the RF muscle (RF_CSA) were measured using US and compared with other physical measures. Associations of US indices with PEW were determined by logistic regression. Irrespective of gender, PEW vs. non-PEW patients had smaller RF, VI muscles, and RF_CSA (all p < 0.001). US muscle sites (all p < 0.001) discriminated PEW from non-PEW patients, but the RF_CSA compared to bio-impedance spectroscopy had a greater area under the curve (AUC, 0.686 vs. 0.581), sensitivity (72.8% vs. 65.8%), and specificity (55.6% vs. 53.9%). AUC of the RF_CSA was greatest for PEW risk in men (0.74, 95% CI: 0.66–0.82) and women (0.80, 95% CI: 0.70–0.90) (both p < 0.001). Gender-specific RF_CSA values (men < 6.00 cm²; women < 4.47 cm²) indicated HD patients with smaller RF_CSA were 8 times more likely to have PEW (AOR = 8.63, 95% CI: 4.80–15.50, p < 0.001). The US approach enabled discrimination of muscle wasting in HD patients with PEW. The RF_CSA was identified as the best US site with gender-specific RF_CSA values to associate with PEW risk, suggesting potential diagnostic criteria for muscle wasting.

Comparison between dual-energy x-ray absorptiometry and bioelectrical impedance for body composition measurements in adults with chronic kidney disease: A cross-sectional, longitudinal, multi-treatment analysis

OBJECTIVE

The aim of this study was to evaluate the agreement between bioelectrical impedance spectroscopy (BIS) and dual-energy x-ray absorptiometry (DXA) for assessment of body composition in patients with chronic kidney disease (CKD).

METHODS

We performed cross-sectional and prospective analyses by DXA and BIS in whole body (BISWB) and segmental (BISSEG) protocols in CKD non-dialysis-dependent (n = 81), hemodialysis (n = 83), peritoneal dialysis (n = 24), and renal transplantation (n = 80) patients. Intraclass correlation coefficient (ICC) and Bland-Altman plots were evaluated. Linear regression analysis was performed for bias assessment and development of equations. Receiver operating characteristics curve was constructed for diagnosis of inadequate error tolerance (DXA - BIS >±2kg).

RESULTS

The agreement with DXA was greater for BISWB than BISSEG; for fat mass (FM; ICC men = 0.894; women = 0.931) than fat-free mass (FFM; ICC men = 0.566; women = 0.525), with greater bias for FFM as muscle increases and for FM in body fat extremes. The agreement was lower for body change analysis (ICC FFM men = 0.196; women = 0.495; ICC FM men = 0.465; women = 0.582). The ratio of extra- to intracellular water (ECW/ICW), body mass index, fat mass index, waist circumference, resistance, and reactance interfered in bias between methods. An ECW/ICW cutoff point of ≥0.7250 for inadequate error tolerance was determined. New prediction equations for FFM (r² = 0.913) and FM (r² = 0.887) presented adequate error tolerance in 55% and 63% compared with 30% and 39% of the original equation, respectively.

CONCLUSION

For body composition evaluation in patients with CKD, BIS applied using the whole body protocol, in normal hydration patients with CKD is as reliable as DXA; BIS must be used with caution in overhydration patients with ECW/ICW ≥ 0.7250. The newly developed equations are indicated for greater precision.

Association of SARC-F Questionnaire and Mortality in Prevalent Hemodialysis Patients

Sarcopenia is common in patients undergoing chronic hemodialysis, which leads to poor outcomes. SARC-F (sluggishness, assistance in walking, rising from a chair, climb stairs, falls), a self-report questionnaire, is recommended as an easily applied tool for screening sarcopenia in older people. However, there are limited data regarding its use in patients undergoing chronic hemodialysis. Therefore, we aimed to evaluate the association between SARC-F and mortality in these patients. SARC-F questionnaire was applied in 271 hemodialysis patients (mean age 64.4 ± 14.3 years) at baseline. The association between SARC-F and mortality during a 24-month follow-up was analyzed. During this follow-up period, 40 patients (14.8%) died. The discriminative power of SARC-F score for predicting mortality was 0.716 (95% confidence interval (CI) = 0.659–0.769; p < 0.001). The best cut-off was a score ≥1, which provided 85.0% sensitivity, 47.2% specificity, 21.8% positive predictive value, and 94.8% negative predictive value. Kaplan–Meier curves showed that patients with SARC-F ≥ 1 exhibited a higher risk of mortality than those with SARC-F < 1 (p < 0.001). Moreover, a stepwise decline in survival with higher SARC-F scores was also observed. After full adjustments, SARC-F ≥ 1 was independently associated with increased mortality (hazard ratio = 2.87, 95% CI = 1.11–7.38; p = 0.029). In conclusion, SARC-F applied for sarcopenia screening predicted mortality in patients undergoing chronic hemodialysis.

The cut-off values of handgrip strength and lean mass index for sarcopenia among patients on peritoneal dialysis

Background

Sarcopenia is common and contributes to a high risk of mortality among general population. There is no consensus regarding the cut-off values for sarcopenia in terms of mortality among chronic kidney disease patients. This study aimed to explore and validate cut-off points of handgrip strength (HGS) and lean mass index (LMI) for estimating the risk of mortality in peritoneal dialysis (PD) patients.

Methods

This single-center prospective cohort study enrolled 1089 incident PD patients between October 2002 and July 2019. All patients were followed until death, transfer to hemodialysis, receiving renal transplantation or the end date of study (December 2019). All participants were randomly sampled to development cohort (70% participants) and validation cohort (30% participants), matched by gender and diabetes. Lean body mass was calculated by using the equation published by our center. Cubic spline regression analysis was used to examine the relationship between HGS or LMI values and mortality, and explore the cut-off points after adjusting for age, diabetes, cardiovascular disease and serum albumin in the development cohort. The derived cut-off values were verified by the agreement rate for predicting mortality and then compared with cut-off values from various clinical guidelines in the validation cohort.

Results

All 1089 patients were followed up with the median of 36.0 (18.0, 71.0) months. In the development cohort, cut-off points for predicting the higher mortality were derived as 24.5 kg and 14 kg of HGS for males and females, 16.7 kg/m² and 13.8 kg/m² of LMI for males and females respectively. In the validation cohort, these cut-off values significantly predicted worse outcomes, with HR 1.96 (1.35, 2.84) of HGS and HR 1.76 (1.26, 2.47) of LMI for all-cause mortality after multivariate adjustment. The newly derived cut-off points of HGS have numerically higher prognostic values in all-cause mortality compared with those from current clinical guidelines, and agreement rates of HGS were 65.2 versus 62.5–64.6 respectively.

Conclusions

The derived cut-off values of HGS and LMI have sufficient and better prognostic value in predicting all-cause mortality in PD patients compared with the cut-off values in the existing guidelines. These cut-off values are only validated in a single population, thus limiting the generalizability.

Feasibility of computed tomography-based assessment of skeletal muscle mass in hemodialysis patients

BACKGROUND

Sarcopenia is a major health issue especially in patients on maintenance hemodialysis. Low skeletal muscle mass is included in the diagnostic criteria for sarcopenia. The skeletal muscle mass is usually evaluated by modalities such as bioimpedance analysis (BIA) or dual-energy X-ray absorptiometry, however the assessment of skeletal muscle mass using computed tomography (CT) images has not been established. The purpose of the study was to investigate the feasibility of the assessment of skeletal muscle mass using CT images in hemodialysis patients.

METHODS

Skeletal muscle mass index (SMI) was measured by BIA and psoas muscle index (PMI) was measured by cross-sectional CT images in 131 patients. The relationship between SMI and PMI and the diagnostic ability of PMI for low muscle mass were evaluated. Furthermore, the patients were followed up and long-term survival in patients with low and high PMI were compared.

RESULTS

PMI measured at the L3 vertebral level was strongly correlated with SMI (r = 0.597, p < 0.001). Age, sex, and SMI were the influencing factors for PMI. Patients with low PMI showed higher incidence rates of mortality during the follow up.

CONCLUSIONS

PMI assessed by CT image can be an alternative to BIA in patients on hemodialysis.

Myostatin and muscle atrophy during chronic kidney disease

Chronic kidney disease (CKD) patients often exhibit a low muscle mass and strength, leading to physical impairment and an increased mortality. Two major signalling pathways control protein synthesis, the insulin-like growth factor-1/Akt (IGF-1/Akt) pathway, acting as a positive regulator, and the myostatin (Mstn) pathway, acting as a negative regulator. Mstn, also known as the growth development factor-8 (GDF-8), is a member of the transforming growth factor-β superfamily, which is secreted by mature muscle cells. Mstn inhibits satellite muscle cell proliferation and differentiation and induces a proteolytic phenotype of muscle cells by activating the ubiquitin-proteasome system. Recent advances have been made in the comprehension of the Mstn pathway disturbance and its role in muscle wasting during CKD. Most studies report higher Mstn concentrations in CKD and dialysis patients than in healthy subjects. Several factors increase Mstn production in uraemic conditions: low physical activity, chronic or acute inflammation and oxidative stress, uraemic toxins, angiotensin II, metabolic acidosis and glucocorticoids. Mstn seems to be only scarcely removed during haemodialysis or peritoneal dialysis, maybe because of its large molecule size in plasma where it is linked to its prodomain. In dialysis patients, Mstn has been proposed as a biomarker of muscle mass, muscle strength or physical performances, but more studies are needed in this field. This review outlines the interconnection between Mstn activation, muscle dysfunction and CKD. We discuss mechanisms of action and efficacy of pharmacological Mstn pathway inhibition that represents a promising treatment approach of striated muscle dysfunction. Many approaches and molecules are in development but until now, no study has proved a benefit in CKD.

Sarcopenia in chronic kidney disease: what have we learned so far?

The term sarcopenia was first introduced in 1988 by Irwin Rosenberg to define a condition of muscle loss that occurs in the elderly. Since then, a broader definition comprising not only loss of muscle mass, but also loss of muscle strength and low physical performance due to ageing or other conditions, was developed and published in consensus papers from geriatric societies. Sarcopenia was proposed to be diagnosed based on operational criteria using two components of muscle abnormalities, low muscle mass and low muscle function. This brought awareness of an important nutritional derangement with adverse outcomes for the overall health. In parallel, many studies in patients with chronic kidney disease (CKD) have shown that sarcopenia is a prevalent condition, mainly among patients with end stage kidney disease (ESKD) on hemodialysis (HD). In CKD, sarcopenia is not necessarily age-related as it occurs as a result of the accelerated protein catabolism from the disease and from the dialysis procedure per se combined with low energy and protein intakes. Observational studies showed that sarcopenia and especially low muscle strength is associated with worse clinical outcomes, including worse quality of life (QoL) and higher hospitalization and mortality rates. This review aims to discuss the differences in conceptual definition of sarcopenia in the elderly and in CKD, as well as to describe etiology of sarcopenia, prevalence, outcome, and interventions that attempted to reverse the loss of muscle mass, strength and mobility in CKD and ESKD patients.

The Glittre activities of daily living as a potential test for functional evaluation of patients on hemodialysis: a validation study

PURPOSE

To investigate the validity and within-day reliability of the Glittre activities of daily living test (Glittre ADL-test) in patients on hemodialysis.

METHODS

Ninety-one patients on hemodialysis were evaluated using Glittre ADL-test, functional tests, health-related quality of life, human activity profile, and social participation. Convergent validity was analyzed by the correlation analysis. The Glittre ADL-test results were compared among different levels of the functional tests, human activity profile, and participation (known-groups validity). Within-day reliability was examined by Intra-class Correlation Coefficient (ICC).

RESULTS

There was a significant moderate to strong correlation between Glittre ADL-test and functional tests (r = 0.62 to 0.66 and -0.70 to -0.44). A significant weak correlation was found between Glittre ADL-test, health-related quality of life (r = 0.28 to 0.32), and human activity profile (r=-0.33). There was no significant correlation with participation. Except for participation level, the Glittre ADL-test results were able to identify individuals with low performance in all evaluated tests and were able to differentiate among inactive and active individuals by human activity profile (p < 0.05). Within-day reliability was evaluated in 42 patients. The ICC was 0.97.

CONCLUSION

The Glittre ADL-test is a reliable test associated with functional parameters and physical aspects related to health-related quality of life, with potential value in the functional evaluation of patients on hemodialysis.Implications for rehabilitationFunctional impairment is a common clinical finding and is an important predictor of poor prognosis in patients on hemodialysis.The Glittre ADL-test has excellent within-day reliability and is a valid instrument for functional assessment in patients on hemodialysis.Activity limitations of patients on hemodialysis can be assessed by Glittre ADL-test.

Sarcopenia and inflammation in patients undergoing hemodialysis

Introduction

Introduction: in individuals with chronic kidney disease, sarcopenia is prevalent and is associated with increased morbidity and mortality, and the occurrence of cardiovascular complications. Objective: to verify the relationship between sarcopenia and inflammation in hemodialysis patients. Methods: a cross-sectional study with 209 patients in five hemodialysis units. Demographic, socioeconomic, body composition, clinical laboratory, and functional data were collected. Sarcopenia was diagnosed according to the European Working Group on Sarcopenia in Older People (grip strength < 27 kg for men and < 16 kg for women; DEXA muscle mass < 7.0 kg/m² for men and < 5.5 kg/m² for women). Inflammation was assessed by C-reactive protein. Results: mean age was 51.9 ± 15.0 years, with a predominance of males (59.3 %). The prevalence of sarcopenia was 29.1 % and that of inflammation was 50.2 %. A Poisson regression analysis showed that sarcopenia was associated with increased hsCRP values (PR: 1.06; 95 % CI: 1.01-1.10; p-value = 0.005); BMI (PR: 0.74; 95 % CI: 0.65-0.84; p-value < 0.001); age (PR: 1.02; 95 % CI: 1.00-1.03; p < 0.001); male (PR: 5.75; 95 % CI: 3.20-10.34; p-value < 0.001); presence of diabetes mellitus (DM) (PR: 1.87; 95 % CI: 1.27-2.74; p-value < 0.001); % body fat (PR: 1.07; 95 % CI: 1.04-1.09; p-value < 0.001). Conclusion: the prevalence of sarcopenia can be considered high in this study, as well as inflammation. Being inflamed, presence of DM, being male, increasing age, and % body fat were risk factors for sarcopenia. On the other hand, increased BMI had a protective role.

Risk Factors for Muscle Loss in Hemodialysis Patients with High Comorbidity

With expanding kidney transplantation programs, remaining hemodialysis patients are more likely to have a high comorbidity burden and may therefore be more prone to lose muscle mass. Our aim was to analyze risk factors for muscle loss in hemodialysis patients with high comorbidity. Fifty-four chronic hemodialysis patients (Charlson Comorbidity Index 9.0 ± 3.4) were followed for 20 weeks using 4-weekly measurements of lean tissue mass, intracellular water, and body cell mass (proxies for muscle mass), handgrip strength (HGS), and biochemical parameters. Mixed models were used to analyze covariate effects on LTM. LTM (-6.4 kg, interquartile range [IQR] -8.1 to -4.8), HGS (-1.9 kg, IQR -3.1 to -0.7), intracellular water (-2.11 L, IQR -2.9 to -1.4) and body cell mass (-4.30 kg, IQR -5.9 to -2.9) decreased in all patients. Conversely, adipose tissue mass increased (4.5 kg, IQR 2.7 to 6.2), resulting in no significant change in body weight (-0.5 kg, IQR -1.0 to 0.1). Independent risk factors for LTM loss over time were male sex (-0.26 kg/week, 95% CI -0.33 to -0.19), C-reactive protein above median (-0.1 kg/week, 95% CI -0.2 to -0.001), and baseline lean tissue index ³10th percentile (-1.6 kg/week, 95% CI -2.1 to -1.0). Age, dialysis vintage, serum albumin, comorbidity index, and diabetes did not significantly affect LTM loss over time. In this cohort with high comorbidity, we found universal and prominent muscle loss, which was further accelerated by male sex and inflammation. Stable body weight may mask muscle loss because of concurrent fat gain. Our data emphasize the need to assess body composition in all hemodialysis patients and call for studies to analyze whether intervention with nutrition or exercise may curtail muscle loss in the most vulnerable hemodialysis patients.

Alterations of body composition patterns in pre-dialysis chronic kidney disease patients

PURPOSE

Body mass index (BMI) might be an inaccurate estimate of detailed body composition because it does not differentiate muscle from fat mass. We sought to understand the effect of kidney function decline on alterations of body composition patterns among pre-dialysis CKD patients.

METHODS

Body composition was measured by multi-frequency bioelectrical impedance analysis (BIA). Low muscle mass was defined as appendicular muscle mass (kg) adjusted to the square of height in meters < 7.0 and 5.7 kg/m² in men and women, respectively. The designation of obesity by percent body fat was ≥ 25% in men and ≥ 30% in women. Alternative definition of obesity by BMI was ≥ 25 kg/m². Visceral fat area cut point was > 100 cm² as indication of abdominal obesity.

RESULTS

Mean age of participants was 61.3 ± 13.8 years (n = 103). The average glomerular filtration rate (GFR) was 34.0 ± 24.2 mL/min/1.73 m². By BIA, the prevalence of low muscle mass was 16.5% and was comparable between both sexes. Obesity by percent body fat was identified in 71.8% of patients and 38.2% had abdominal obesity. Using BMI criteria, the prevalence of obesity was less common (55.3%) and associated with under-identification of obesity by 27.0%. Low muscle mass and obesity by percent body fat were more prevalent in the more advanced stages of CKD. By multivariable regression analysis, a 10 mL/min/1.73 m² decline in GFR was associated with a 0.59 kg reduction of total body muscle mass (p = 0.01), but not fat mass or BMI, after adjusting for confounders.

CONCLUSION

Low muscle mass was prevalent among pre-dialysis CKD patients. BMI commonly classified obese CKD individuals by percent body fat criteria as non-obese. The reduction of muscle mass was associated with GFR decline.

Muscle mass assessment in renal disease: the role of imaging techniques

Muscle wasting is a frequent finding in patients with chronic kidney disease (CKD), especially in those with end-stage kidney disease (ESKD) on chronic dialysis. Muscle wasting in CKD is a main feature of malnutrition, and results principally from a vast array of metabolic derangements typical of the syndrome, that converge in determining reduced protein synthesis and accelerated protein catabolism. In this clinical setting, muscle wasting is also frequently associated with disability, frailty, infections, depression, worsened quality of life and increased mortality. On these grounds, the evaluation of nutritional status is crucial for an adequate management of renal patients, and consists of a comprehensive assessment allowing for the identification of malnourished patients and patients at nutritional risk. It is based essentially on the assessment of the extent and trend of body weight loss, as well as of spontaneous dietary intake. Another key component of this evaluation is the determination of body composition, which, depending on the selected method among several ones available, can identify accurately patients with decreased muscle mass. The choice will depend on the availability and ease of application of a specific technique in clinical practice based on local experience, staff resources and good repeatability over time. Surrogate methods, such as anthropometry and bioimpedance analysis (BIA), represent the most readily available techniques. Other methods based on imaging modalities [dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and whole body computed tomography (CT)] are considered to be the "gold standard" reference methods for muscle mass evaluation, but their use is mainly confined to research purposes. New imaging modalities, such as segmental CT scan and muscle ultrasound have been proposed in recent years. Particularly, ultrasound is a promising technique in this field, as it is commonly available for bedside evaluation of renal patients in nephrology wards. However, more data are needed before a routine use of ultrasound for muscle mass evaluation can be recommended in clinical practice.

Intake of polyunsaturated fatty acids and ω-3 are protective factors for sarcopenia in kidney transplant patients

OBJECTIVES

The aim of this study was to associate dietary intake with sarcopenia and its components in kidney transplant patients (KTPs).

METHODS

A cross-sectional study was performed with 125 KTPs. Strength was evaluated by handgrip strength (HGS) and appendicular muscle mass was estimated by bioelectrical impedance. Functional capacity was assessed by 4-m walking test. Sarcopenia was diagnosed by revised European Consensus on Definition and Diagnosis (2019). Dietary assessment was carried out through two 24-h dietary recalls. It evaluated the consumption of energy (kcal), carbohydrates, protein (total and from animal and vegetable food sources), total fat, saturated fatty acids, monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and ω-3 (g) and ω-6 (g).

RESULTS

Intake of ω-3 was positively associated with appendicular skeletal muscle mass index (ASMI; kg/m²). The greater intake of PUFA (g and %) and ω-3 (g) was associated with lower chance to present low ASMI and sarcopenia. None of the other dietary components evaluated in the present study were associated with ASMI and sarcopenia. Walking speed and HGS were not associated with dietary variables.

CONCLUSIONS

Intake of ω-3 and PUFAs are protective factors for sarcopenia and low muscle mass, but not for strength and functional capacity, in KTPs.

An overview of frailty in kidney transplantation: measurement, management and future considerations

The construct of frailty was first developed in gerontology to help identify older adults with increased vulnerability when confronted with a health stressor. This article is a review of studies in which frailty has been applied to pre- and post-kidney transplantation (KT) populations. Although KT is the optimal treatment for end-stage kidney disease (ESKD), KT candidates often must overcome numerous health challenges associated with ESKD before receiving KT. After KT, the impacts of surgery and immunosuppression represent additional health stressors that disproportionately impact individuals with frailty. Frailty metrics could improve the ability to identify KT candidates and recipients at risk for adverse health outcomes and those who could potentially benefit from interventions to improve their frail status. The Physical Frailty Phenotype (PFP) is the most commonly used frailty metric in ESKD research, and KT recipients who are frail at KT (~20% of recipients) are twice as likely to die as nonfrail recipients. In addition to the PFP, many other metrics are currently used to assess pre- and post-KT vulnerability in research and clinical practice, underscoring the need for a disease-specific frailty metric that can be used to monitor KT candidates and recipients. Although frailty is an independent risk factor for post-transplant adverse outcomes, it is not factored into the current transplant program risk-adjustment equations. Future studies are needed to explore pre- and post-KT interventions to improve or prevent frailty.

Relation of Serum 25-Hydroxyvitamin D Status with Skeletal Muscle Mass and Grip Strength in Patients on Peritoneal Dialysis

The aim of this study was to investigate the association of serum 25-hydroxyvitamin D (25(OH)D) with skeletal muscle mass (SMM) and grip strength in patients on peritoneal dialysis. In this single center retrospective study, a total of 113 incident peritoneal dialysis patients (65 men, 48 women) were included. Serum concentrations of 25(OH)D were measured through radioimmunoassay. Hypovitaminosis was classified when the level of serum 25(OH)D was <20 ng/mL. SMM was assessed through bioelectrical impendence analysis, whereas grip strength was assessed through handgrip dynamometer. On the basis of expert consensus of the Asian Working Group for Sarcopenia, low muscle mass was defined as relative skeletal mass index (RSMI)<7.0 kg/m² for men and <5.7 kg/m² for women. The general linear and noncondition logistical regression model were employed to explore the association between vitamin D and both muscle mass and grip strength. The mean serum 25(OH)D level was 19.3(±8.4) ng/mL. Compared with 25(OH)D<20 ng/mL, the mean values of SMM, appendicular skeletal muscle mass (ASM), ASMI, and grip strength were higher for ≥20 ng/mL. Subjects (25(OH)D<20 ng/mL) had a greater proportion of low SMM (55.8%) and low grip strength (66.4%). After adjusting for multiple factors, serum 25(OH)D was positively associated with grip strength (β=0.18, p=0.009), ASM (β=0.14, p<0.001), and RSMI (β=0.07, p<0.001); 25(OH)D<20 ng/mL was significantly associated with low grip strength (OR=2.97, 95% CI: 1.17-7.55), and low SMM (OR=2.73, 95% CI: 1.15-6.45). The present study demonstrated a positive association between serum vitamin D status and skeletal muscle mass and grip strength in patients on peritoneal dialysis.

Differences between anthropometric and bioimpedance measurements of muscle mass in the arm and hand grip and pinch strength in patients with chronic kidney disease

BACKGROUND & AIMS

Chronic kidney disease (CKD) patients are at increased risk of sarcopenic muscle wasting, with increased mortality risk. Simple screening tests are required to detect sarcopenia to allow for interventional therapies. We wished to compare anthropometric and multifrequency bioimpedance (MFBIA) measurements of arm composition and muscle strength.

METHODS

We measured segmental MFBIA, mid arm upper circumference (MUAC) and triceps skin fold thickness (TSF), hand grip strength (HGS) and pinch strength (PS) in CKD patients attending out-patient review.

RESULTS

We reviewed 146 patients; 94 male (64.4%), 93 (63.7%) diabetic, mean age 70.5 ± 15 years, weight 77.6 ± 17.1 kg, with a mean HGS of 25.2 ± 10.4, and PS 5.0 ± 1.9 kg. HGS and PS were correlated (r = 0.63, p < 0.001). Male patients had greater HGS and PS (28.3 ± 10.1 vs 19.7 ± 7.0 kg; and 5.3 ± 2.0 vs 4.3 ± 1.1 kg, p < 0.05) with greater arm muscle (3.2 ± 0.7 vs 2.4 ± 0.7 kg, p < 0.05) and less arm fat (1.8 ± 1.3 vs 2.9 ± 1.8 kg, p < 0.05), whereas there was no difference in anthropometric measurements of mid upper arm muscle or fat area. Whereas both HGS and PS correlated positively with MFBIA arm lean mass (r = 0.55, r = 0.37, p < 0.001) and negatively for arm fat mass (r = -0.4, p < 0.001, r = -0.32, p = 0.001) respectively, there were no correlations with anthropometric derived estimates of upper arm muscle or fat.

CONCLUSIONS

In CKD patients, segmental MFBIA measurements of the arm, but not those derived from anthropometric measurements demonstrate gender differences and correlate with arm muscle strength, whereas there were no such correlations with anthropometric estimates of upper arm muscle or fat.

The Impact of Home-Based Exercise Program on Physical Function of Chronic Kidney Disease Patients: A Meta-Analysis of Randomized Controlled Trials

Background Home-based exercise program showed the potential in improving physical function of chronic kidney disease patients, and it might need low associated costs. We conducted a systematic review and meta-analysis to explore the impact of home-based exercise program on physical function of chronic kidney disease patients.

Methods PubMed, EMBASE, Web of science, EBSCO, and Cochrane library databases were systematically searched. This meta-analysis included randomized controlled trials (RCTs) assessing the effect of home-based exercise program on physical function of chronic kidney disease patients. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcomes were 6-min walk test and grip strength change.

Results Seven RCTs were included in the meta-analysis. Overall, compared with control intervention in chronic kidney disease patients, home-based exercise program could significantly improve 6-min walk test (MD=79.01; 95% CI=22.39–135.62; P=0.006) and grip strength (SMD=0.52; 95% CI=0.14–0.89; P=0.007), but showed no impact on pain scores (SMD=−1.43; 95% CI=−3.75 to 0.88; P=0.22), Kidney Disease Quality of life including symptom/problem list (SMD=1.92; 95% CI=−1.06 to 4.90; P=0.21), effects of kidney disease (SMD=−3.69; 95% CI=−8.56 to 1.19; P=0.14), or burden of kidney disease (SMD=1.04; 95% CI=−0.75 to 2.82; P=0.26).

Conclusions Home-based exercise program might improve physical function for chronic kidney disease, and more RCTs should be conducted to confirm this issue.

Abdominal Skeletal Muscle Index as a Potential Novel Biomarker in Adult Fontan Patients

Background

Fontan palliation results in a chronic multisystem disorder with diminished exercise capacity and increased risk of muscle wasting. The aims of this study were to assess the feasibility of skeletal muscle mass measurements in Fontan patients undergoing magnetic resonance imaging liver surveillance to compare muscle mass with a historic control and to assess its correlation with cardiorespiratory fitness.

Methods

Skeletal muscle area (SMA) and skeletal muscle index (SMI) were measured at T12 and L3. A young, healthy historic cohort was used as a comparison group.

Results

Forty patients with a Fontan circulation (mean age, 25.5 ± 7.9 years; 50% were men) were included. Measurements of SMA and SMI were feasible and highly reproducible. Mean SMA and SMI were significantly lower in women compared with men at both T12 (SMA: 25.1 ± 4.9 cm² vs 33.5 ± 8.4 cm², P < 0.001; SMI: 9.7 ± 2.1 cm²/m² vs 11.3 ± 2.7 cm²/m², P = 0.045) and L3 (SMA: 121 ± 12 cm² vs 162 ± 24 cm², P < 0.001; SMI: 46.9 ± 7.0 cm²/m² vs 54.5 ± 7.4 cm²/m², P = 0.002). Mean SMI at L3 was significantly lower in the male Fontan population compared with the healthy historic cohort (54.5 ± 7.4 cm²/m² vs 60.9 ± 7.8 cm²/m², P < 0.001), but was similar for women (46.9 ± 7.0 cm²/m² vs 47.5 ± 6.6 cm²/m², P = 0.692). SMI at L3, but not at T12, was positively correlated with peak oxygen consumption, oxygen pulse, and workload. Four patients (10%) met criteria for muscle wasting in the sarcopenic range based on L3 measurements.

Conclusions

Abdominal skeletal muscle mass can be reproducibly determined on surveillance liver magnetic resonance imaging scans. Muscle wasting appears to occur commonly in Fontan patients. Further research is needed to better define the value of SMI as a biomarker in the Fontan population.

Using Sonography to Objectively Gauge Muscle Wasting: A Multiple Case Report

End-stage renal disease (ESRD) is a prevalent disease that results from kidney failure in the last stage of chronic kidney disease. This disease has many chronic and debilitating symptoms, including muscle wasting. Unfortunately, current methods to diagnose muscle wasting, in this patient population, are rather imprecise and/or expensive. To develop a better method, this study examined the use of sonography across four separate patients with ESRD in a typical clinical setting. Multiple muscle measurements were taken in the patients’ upper arm via sonography, which were compared to laboratory test results and skinfold measurements. This multiple case comparison demonstrates the feasibility of using sonography to measure subcutaneous tissue and muscle mass in this patient population. It also has the potential to correlate with or support other clinical measures of disease severity. Further study is recommended to examine these correlations and to identify clinical implications for sonographic measurement of overall muscle wasting.

Identification of the most clinically useful skeletal muscle mass indices pertinent to sarcopenia and physical performance in chronic kidney disease

AIM

Patients with chronic kidney disease (CKD) are characterised by low skeletal muscle mass that negatively impacts physical performance. Operational definitions of 'low muscle mass' are inconsistent, and it is unknown how different skeletal muscle mass indices affect the relationship between muscle mass and physical function.

METHODS

Appendicular skeletal muscle mass (ASM) was measured by dual-energy X-ray absorptiometry in 72 CKD patients. Along with crude ASM, alternative muscle indices were calculated adjusting for height, height-squared, body mass, and BMI. Physical performance was assessed by handgrip strength, sit-to-stand tests, gait speed, the incremental shuttle walk test and 'Short Physical Performance Battery'.

RESULTS

Prevalence of 'low muscle mass' ranged from 26% to 35% of patients depending on the criteria used. The relationship between muscle mass indices and physical function differed for each criteria. Using average coefficients, the association with overall physical function and muscle indices were as follows: crude ASM (r = .258), ASM/height (r = .249), ASM/height-squared (r = .332), ASM/body mass (r = .249) and ASM/BMI (r = .206). Muscle adjusted for markers of adiposity (ASM/body fat %, r = .266; ASM/fat mass, r = .338) provided the best overall associations with physical function.

CONCLUSION

The use of alternative muscle mass indices provide different estimates of 'low muscle mass' prevalence, and the strongest (and most useful definition in regard to functional status) involves adjustment for either total or relative body fat. ASM adjusted for adiposity may be physiologically and clinically more relevant in patients with renal disease.

Comparative Analysis Between Computed Tomography and Surrogate Methods to Detect Low Muscle Mass Among Colorectal Cancer Patients

BACKGROUND

We aimed to evaluate the agreement between computed tomography (CT) and surrogate methods applied in clinical practice for the assessment of low muscle mass. In addition, we assessed the association between different muscle-assessment methods and nutrition status, as well as the prognostic value of low muscle mass on survival in patients with colorectal cancer (CRC).

METHODS

This is a cohort including 188 CRC patients with 17 months' follow-up (interquartile range: 12-23 months) for mortality. Low muscle mass was evaluated by corrected mid-upper arm muscle area (AMAc) and calf circumference, skeletal muscle mass by bioelectrical impedance analysis (BIA), muscle deficit by physical examination with the Patient-Generated Subjective Global Assessment (PG-SGA), and lumbar muscle cross-sectional area by CT (reference method).

RESULTS

The prevalence of low muscle mass ranged from 9.6% to 54.3% according to the method used. The physical examination had the highest κ coefficient compared with CT. Low muscularity was associated with the presence of malnutrition, lower body fat, and low phase angle. The Cox regression models-adjusted for age, sex, and treatment 3 months before study inclusion-showed that severe muscle loss measured by BIA and CT and low muscle mass measured by PG-SGA predicted higher mortality rates.

CONCLUSIONS

Compared with CT, the physical examination had the best agreement to assess low muscle mass. Low muscle mass assessed by PG-SGA, BIA, and CT showed similar prognostic values for survival.

Genetic and epigenetic Muller's ratchet as a mechanism of frailty and morbidity during aging: a demographic genetic model

Mutation accumulation has been proposed as a cause of senescence. During this process, age-related genetic and epigenetic mutations steadily accumulate. Cascading deleterious effects of mutations might initiate a steady "accumulation of deficits" in cells, despite the existence of repair mechanisms, leading to cellular senescence and functional decline of tissues and organs, which ultimately manifest as frailty and disease. Here, we investigate several of these aspects in differentiating cell populations through modeling and simulation using the Moran birth-death (demographic) process, under several scenarios of mutation accumulation. Deleterious mutations seem to rapidly accumulate particularly early in the course of life, during which the rate of cell division is high, thereby exerting a greater effect on subsequent cellular senescence. Our results are compatible with the principle of the Muller's ratchet taking place in asexually reproducing organisms. The ratchet speed in a given tissue depends on the size of the cell population, mutation rate and the impact of such mutations on cell phenotypes. It varies substantially among cells in different tissues and organs due to heterogeneity in relation to cell and organ-specific demographic features. Ratchet accelerates particularly after middle age, resulting in a synergistic fitness decay at the level of cell populations. We extend Fisher's average excess concept and rank order scale to interpret differential phenotypic effects of the increase of the mutation load among cell populations within a given tissue. We postulate that classical evolutionary genetic models can explain, at least in part, the origins of frailty, subclinical conditions, morbidity and the health consequences of senescence.

Serum creatinine to cystatin C ratio predicts skeletal muscle mass and strength in patients with non-dialysis chronic kidney disease

BACKGROUND & AIMS

Muscle wasting is highly prevalent in patients with chronic kidney disease (CKD). However, the assessment of skeletal muscle mass and strength in clinical settings is not commonly available. We aimed to evaluate the feasibility of serum creatinine/cystatin C (Cr/CysC) ratio in the assessment of muscle wasting.

METHODS

In 272 patients with CKD aged 66.5 ± 15.1 years, skeletal muscle mass and handgrip strength (HGS) were assessed. Skeletal muscle index (SMI) was calculated as skeletal muscle mass/height². Low muscle mass was defined as SMI below the sex-specific 10th percentile of study population and low handgrip strength as less than 26 Kg for men and 18 Kg for women.

RESULTS

The Cr/CysC ratio was significantly lower in both the low SMI and low HGS groups. Moreover, the Cr/CysC ratio correlated with SMI (r = .306, p < .001) and HGS (r = .341, p < .001). After adjusting for confounding factors, age, sex, waist circumference, body fat mass, and Cr/CysC ratio were independently associated with SMI, whereas age, sex, diabetes, hemoglobin, estimated glomerular filtration rate, urine protein/creatinine ratio, SMI, and Cr/CysC ratio were independently associated with HGS.

CONCLUSIONS

Cr/CysC ratio appears to be a promising surrogate marker for detecting muscle wasting in patients with CKD. Further studies are needed to extend our findings.