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

High level of soluble tumor necrosis factor receptors is associated with lower residual diuresis volume in patients on hemodialysis: An exploratory study

OBJECTIVE

Patients on hemodialysis commonly present with elevated inflammatory markers. It is noteworthy, however, that higher levels of these markers may deteriorate residual renal function in in these individuals. Further investigation is essential to clarify the potential link between systemic chronic inflammatory parameters and residual diuresis volume in this population, particularly when accounting for confounding variables such as body composition. This study aimed to explore the possible relationship between inflammatory parameters and residual diuresis volume in patients on hemodialysis.

METHODS

Blood samples were collected from patients on hemodialysis for the analysis of soluble receptors: 1) tumor necrosis factor receptor 1 (sTNFR1), 2) tumor necrosis factor receptor 2 (sTNFR2), and 3) leptin. Confounding variables, such as gender, age, duration of hemodialysis, Kt/V (a measure of dialysis adequacy), and body composition assessed using the dual-energy X-ray absorptiometry (DXA), were also evaluated. Data analyses were conducted using both single and multiple regression models, adjusted for the confounding parameters.

RESULTS

Of the total sixty participants, 27 (45%) were classified as anuric, and 33 (55%) as non-anuric. High sTNFR1 plasma levels were associated with a lower residual diuresis volume, irrespective of adjustments for confounding parameters (R² = 25.4%; β = 0.504; p < 0.001).

CONCLUSION

This study supports the hypothesis that higher systemic levels of sTNFR1 may deteriorate residual renal function, as evidenced by the lower residual diuresis volume observed in patients on hemodialysis. These findings suggest that interventions aimed at reducing systemic inflammation may be beneficial in preserving residual renal function and improving clinical outcomes in these patients. Chronic Kidney Disease (CKD) is characterized by any persistent alteration or abnormality in kidney structure or function lasting over ninety days [1]. CKD's subtle onset complicates diagnosis, and once established, it often progresses irreversibly [2]. Recognized globally as a major public health issue [3], CKD affects 10-13% of adults in economically advanced countries [1]. In Brazil, CKD poses significant healthcare challenges, causing over 35,000 deaths annually and incurring substantial treatment costs [4]. Projections indicate around 10 million CKD cases in Brazil, with about 90,000 individuals requiring dialysis [5,6]. This data underscores the urgent need to address CKD as a critical health challenge and develop comprehensive strategies to mitigate its impact on public health and healthcare costs.

Comprehensive Insights into Sarcopenia in Dialysis Patients: Mechanisms, Assessment, and Therapeutic Approaches

Sarcopenia, defined as the progressive loss of muscle mass, strength, and function, is largely prevalent but still clinically underrecognized among patients undergoing chronic dialysis therapy. The pathogenesis involves a complex interplay of chronic inflammation, oxidative stress, metabolic acidosis, hormonal imbalances, protein waste, malnutrition, and reduced physical activity. This multifactorial condition profoundly impairs quality of life and may lead to significant clinical consequences, including frailty, an increased risk of falls and hospitalization, and elevated mortality. Despite its clinical relevance, sarcopenia often remains underdiagnosed due to inconsistent diagnostic criteria and challenges in assessing body composition in dialysis populations. Therapeutic strategies, including tailored exercise programs, nutritional interventions, and pharmacological treatments, are essential to mitigate muscle loss and improve patient outcomes. Early identification and routine sarcopenia assessment in clinical practice could play a pivotal role in enhancing the management of dialysis patients. A multidisciplinary, personalized approach is necessary to address the diverse factors contributing to sarcopenia and to improve the overall prognosis and quality of life for this vulnerable population.

Quality matters: chronic kidney disease progression is associated with reduced muscle strength independently of changes in skeletal muscle mass: an observational study

Background

Chronic kidney disease (CKD) is commonly associated with multifactorial neuromuscular impairments. Few studies have investigated CKD-induced changes in maximal voluntary force (MVF), and even fewer have longitudinal follow-up. The aim of this study is to investigate whether CKD progression modifies the relationship between skeletal muscle mass and force, and the prevalence of sarcopaenia and sarcopenic obesity.

Methods

The data used were prospectively collected during routine check-ups in a network of nutritional centres in Mexico and retrospectively analysed. From a dataset of 5430 patients, we selected 1098 patients with available anthropometric, kidney function, handgrip and bioimpedance data. The relationship between appendicular skeletal muscle mass (ASM) and MVF was investigated using mixed models and adjusted for age, sex, body mass index, physical activity level and CKD aetiology. Sarcopaenia prevalence were tested across period of follow-up using the Cochran-Mantel-Haenzen for repeated measures and across CKD stages using the Chi-2 test.

Results

After normalization with ASM, MVF was higher in CKD G1-G3 compared with G4 and G5 (P ≤ .001, Cohen's d = 0.270-0.576). Slopes between MVF and ASM were lower in CKD G3, G4 and G5 than in CKD G1-G2 [-2.268 (-3.927, -0.609), P  = .008; -2.694 (-4.593, -0.794), P  = .006; -3.675 (-5.326, -1.725), P  < .001, respectively]. The prevalence of sarcopaenia and sarcopaenic obesity did not differ across CKD stages, but recovery was most commonly observed in CKD G1-G2. Slope analysis showed an independent interaction between the slopes of kidney function and ASM on MVF evolution over time.

Conclusions

CKD negatively, progressively and independently affects the neuromuscular system, and force production is reduced for any given muscle mass as CKD progresses. While no association was found between CKD stage and prevalence of sarcopaenia, recovery was more frequent in the early CKD stages. These results suggest the importance of early rehabilitation programs to improve musculoskeletal health, quality of life and survival in CKD patients.

Sarcopenia is associated with survival in patients awaiting kidney transplant

BACKGROUND

The relationship of sarcopenia to frailty and other survival determinants in patients waitlisted for kidney transplant is not well characterized. Our goal was to evaluate the relationship of muscle area to functional and frailty metrics and its impact on survival in patients waitlisted for kidney transplant.

METHODS

Among 303 consecutively listed transplant candidates, 172 had a computed scan within 3 months of frailty and biochemical testing that permitted muscle area evaluation. Third lumbar level psoas muscle indices (total bilateral psoas area/height2) were calculated. Testing included frailty metrics, treadmill and pedometer ability, troponin, and brain natriuretic peptide levels. Associations between muscle area, demographic, biochemical, and frailty measures were analyzed. Log-rank test was used to evaluate waitlist survival on the basis of muscle area, and multivariate Cox proportional hazards modeling was used to evaluate factors independently associated with survival.

RESULTS

Demographic factors associated with third lumbar level psoas muscle indices include male sex (P < .001), race (P = .02), age (P = .004), and body mass index (P < .0001). Grip strength, treadmill ability, and Sit-Stands positively correlated with third lumbar level psoas muscle indices (P < .01). Brain natriuretic peptide and Up and Go negatively correlated with third lumbar level psoas muscle indices (P < .01). Survival was significantly associated with third lumbar level psoas muscle indices (P = 0.02). Treadmill ability, Sit-Stands, Up and Go, race and muscle area were most closely associated with waitlist survival on multivariate modeling.

CONCLUSION

Sarcopenia as assessed with muscle area measurements is independently associated with kidney waitlist survival. Functional ability and muscle area may be overlapping, but noncongruent, determinants of waitlist outcomes and may need to be individually assessed to create the most predictive survival model.

Utility of ultrasound in measuring quadriceps muscle thickness in patients receiving maintenance hemodialysis: comprehensive systematic review and meta-analysis

BACKGROUND

Muscle wasting, a prevalent issue in hemodialysis patients, is effectively assessed by measuring quadriceps muscle thickness, a crucial health indicator. This meta-analysis integrates findings from various studies on the application of ultrasonography (US) for measuring the thickness of quadriceps muscles in patients undergoing maintenance hemodialysis.

DESIGN AND METHODS

We conducted a thorough literature search across PubMed, Scopus, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science up to April 2023. The R software's Meta package was used for mean difference analysis of quadriceps rectus femoris thickness (QRFT) and quadriceps vastus intermedius thickness (QVIT) between hemodialysis patients and healthy controls. All of the patients entered the meta-analysis are Caucasians. Sub-group analyses based on measurement sites and pre- and post-dialysis comparisons were performed.

RESULTS

Among 15 studies with 1584 patients, a significant decrease in QRFT and QVIT was observed in hemodialysis patients compared to healthy controls (mean difference = 0.40 cm, 95% CI: -0.49 to -0.31 and 0.46 cm, respectively). Right and left QRFT were notably thinner in hemodialysis patients (RT: mean difference = 0.39 cm; LT: mean difference = 0.42 cm). Similarly, right and left QVIT were notably thinner in hemodialysis patients (RT: mean difference = 0.45 cm; LT: mean difference = 0.47 cm). No significant pre- and post-dialysis QRFT differences were found.

CONCLUSION

Ultrasonography is a reliable, accessible tool for assessing quadriceps muscle thickness in hemodialysis patients, revealing consistent muscle thickness reduction. These findings emphasize the need for routine muscle health monitoring in this population and support ultrasound use for regular assessments.

Association between muscle strength and echogenicity using greyscale ultrasound software: a diagnostic accuracy study in kidney transplant candidates

BACKGROUND

Advanced chronic kidney disease disrupts the delicate equilibrium between protein anabolism and catabolism, leading to alterations in muscle quantity, quality, and function. Musculoskeletal ultrasound emerges as a promising assessment tool due to its widespread availability and high reliability.

AIM

To evaluate the efficacy of rectus femoris (RF) echogenicity, measured using greyscale software, in identifying diminished muscle quality and strength in candidates for kidney transplant.

DESIGN

Post-hoc diagnostic accuracy study.

SETTING

Outpatients in a multimodal prehabilitation program pre kidney transplantation (KT).

POPULATION

Patients on the waiting list for KT.

METHODS

Sensitivity, specificity, likelihood ratios and area under the curve (AUC) for diagnostic efficacy of echogenicity (index test) assessed with the ImageJ software greyscale as a potential marker of quadriceps muscle weakness (reference test) were calculated. Muscle weakness was considered as maximal voluntary isometric contraction of the quadriceps (Q-MVIC) <40% of body weight. Other variables included body composition parameters derived from multifrequency electrical bioimpedance, upper limb muscle strength (handgrip), and RF thickness assessed by ultrasound. Statistical tests: Chi-square, t-Student, Pearson correlation coefficients (r), bivariate and multivariate logistic regression models. Statistical significance level ≤0.05.

RESULTS

Of 112 patients (mean age: 63.6, 76% male), 72 (63.7%) exhibited quadriceps weakness, while 80 (70.8%) had some degree of overhydration (extracellular water/total body water ratio >0.390). The echogenicity cut-off point of highest concordance with muscle weakness was 70, boasting a sensitivity of 83%, specificity of 57%, and AUC of 0.671 (CI 95% 0.570-0.772 [P=0.003]). Echogenicity >70 was associated with a 3.4-fold higher risk of muscle weakness (crude OR = 3.4 [CI95% 1.4 to 8.0]), which persisted after adjusting for age, height, weight and RF thickness.

CONCLUSIONS

The RF echogenicity exhibits fair validity in identifying muscle weakness among candidates for KT. However, it cannot be endorsed as a standalone diagnostic tool in this population.

CLINICAL REHABILITATION IMPACT

Early identification of muscle weakness would advance efforts to mitigate morbidity and mortality through targeted measures.

Thresholds of handgrip strength for all-cause mortality in patients with chronic kidney disease: a secondary systematic review with dose-response meta-analysis

BACKGROUND

Although handgrip strength is associated with all-cause mortality in patients with chronic kidney disease (CKD), whether this relationship is dose-related is unknown. Therefore, we examined dose-response relationships between handgrip strength and all-cause mortality in CKD patients based on previous studies by meta-analysis.

METHODS

Data sources included three electronic databases (PubMed, Web of Science, and Embase) from inception through October 2023. The included cohort was a CKD population not limited to disease stage, and their handgrip strength was objectively measured. Two researchers independently screened studies, extracted data, and assessed the risk of bias. We utilized estimates of handgrip strength categories using robust-error meta-regression (REMR), pooled study-specific estimates, and established dose-response relationships. Outcomes of interest included only all-cause mortality.

RESULTS

A total of 18 studies with 4810 participants (aged 47-71 years) were included. REMR modeling showed a U-shaped trend of association between handgrip strength and all-cause mortality in patients with CKD. Higher handgrip strength values, from 10 kg to approximately 28 kg, were associated with lower mortality risk. After that, the risk of death increased slightly.

CONCLUSION

A U-shaped association exists between handgrip strength and all-cause mortality risk in CKD patients. Future studies with quantitative measurements for each CKD stage will help to determine precise relative risk estimates between handgrip strength and mortality risk in patients with different stages of CKD.

Perceptions of healthcare providers on benefits, risks and barriers regarding intradialytic exercise among haemodialysis patients

PURPOSE

Clinical guidelines call for the inclusion of exercise interventions in every patient's dialysis session, but these recommendations are rarely adopted. Healthcare providers play a key role in this. Therefore, the aim of this study was to explore how healthcare providers perceive the benefits, risks and barriers of intradialytic exercise (IDE).

METHODS

We conducted 21 individual, semi-structured interviews with 11 nurses, 5 nephrologists, 3 training assistants and 2 managers from two dialysis centres in Slovakia. Verbatim transcripts of digitally recorded interviews were thematically analysed using MAXQDA®.

RESULTS

Participants reported the benefits of IDE as improvements in patients' physical and psychosocial functioning, independence and self-efficacy, clinical profile and quality of therapy. As risks of IDE, they most frequently reported exercise-related damage to vascular access, insufficient individualization of training and musculoskeletal injuries. The presence of psychological problems among patients was reported as a major barrier for initiating and maintaining patients' exercise. Other reported barriers included limitations in financial and personnel resources of haemodialysis care.

CONCLUSIONS

Safe and sustainable implementation of IDE, which might improve a patient's well-being, need to be prescribed in alignment with the patient's clinical profile, be delivered individually according to the patient's characteristics and requires adjustments in the available resources.

Validation of Ultrasound Measurement of Vastus Lateralis for Appendicular Skeletal Muscle Mass in Chronic Kidney Disease Patients with Hemodialysis

BACKGROUND

Chronic kidney disease patients undergoing hemodialysis (HD) are at a high risk of developing sarcopenia. This study aimed to validate the performance of ultrasound (US) measurements of the vastus lateralis (VL) for estimating muscle mass and diagnosing sarcopenia in CKD patients with HD.

METHODS

Forty-six patients were enrolled in this study. Muscle thickness (MT) and echo intensity (EI) of VL, physical performance, and biochemical markers were collected to establish a linear regression model for predicting appendicular skeletal muscle mass (ASM), using dual-energy X-ray absorptiometry (DXA) as the reference standard. The model's performance was validated, and its diagnostic accuracy for sarcopenia was also evaluated.

RESULTS

An ASM prediction model was derived: -20.17 + 1.90 × MT_VL (cm) + 1.58 × male + 0.16 × Height (cm) + 0.09 × Weight (kg) + 0.05 × Age (year), with a standard estimated error of 1.44 kg and adjusted R-squared of 0.84. The model exhibited high correlation and an acceptable limit of agreement, compared to DXA measurement. EI displayed a negative correlation with ASM and MT.

CONCLUSIONS

The ASM adjusted with BMI demonstrated superior performance in diagnosing sarcopenia compared to the ASM adjusted with height. Ultrasound provides a cost-effective bedside tool for evaluating muscle conditions in HD patients.

Myosteatosis: an underrecognized risk factor for mortality in non-dialysis chronic kidney disease patients

BACKGROUND

Low muscle mass quantity and quality (myosteatosis) can be evaluated by computed tomography (CT) by measuring skeletal muscle area and muscular attenuation, respectively, at the third lumbar vertebra. We aimed to define cut-off points of skeletal muscle area and muscular attenuation to predict mortality in non-dialysis chronic kidney disease (CKD) patients.

METHODS

We conducted a retrospective study including non-dialysis CKD patients over two years, who underwent an opportunistic computed tomography within a two year period, and for whom creatinine was measured within 90 days of CT. Skeletal muscle area was normalized for stature to calculate the skeletal muscle index. Area under the receiver operating characteristic (AuROC) curve and Youden's index were used, to identify the cut-point, separately according to sex.

RESULTS

One hundred sixty-seven patients (50.9% male, mean age of 68.3 ± 16.4 years) were included, most with CKD stages 3 and 4. During a median follow-up of 4.9 (4.2) years, 39 (23.4%) patients died. Muscular attenuation showed a better ability to predict mortality (AuROC curve 0.739 [95% CI 0.623-0.855] in women and 0.744 in men [95% CI 0.618-0.869]) than skeletal muscle index (AuROC curve 0.491 [95% CI 0.332-0.651] in women and 0.711 [95% CI 0.571-0.850] in men). For muscular attenuation, the best cut-off values to predict mortality were 27.56 Hounsfield units in women and 24.58 Hounsfield units in men. For skeletal muscle index, the best cut-off values were 38.47 cm2/m2 in women and 47.81 cm2/m2 in men. In univariable Cox-regression both low muscle mass and myosteatosis were associated with increased mortality. In multivariable Cox-regression models only myosteatosis maintained a significant association with mortality (Hazard Ratio 2.651 (95% CI 1.232-5.703, p = 0.013)).

CONCLUSIONS

We found sex-specific cut-off values for muscle parameters using CT analysis in non-dialysis CKD patients that were associated with mortality. In this population, myosteatosis may be more closely associated with mortality than muscle quantity.

Comparing bioimpedance spectrometry and traditional creatinine kinetics methods for the assessment of muscle mass in peritoneal dialysis patients

Background

Sarcopenia is a common and serious problem in patients receiving peritoneal dialysis (PD). Lean tissue mass (LTM) by bioimpedance spectrometry is a reasonably accurate method for measuring muscle mass. Fat-free edema-free body mass (FEBM) as determined by the creatinine kinetics method is a traditional method but evidence to support its use is limited.

Methods

We studied 198 new PD patients. Their serial LTM and FEBM were reviewed and compared by the Bland and Altman method. Multi-variable regression model was used to determine factors associated with the disparity between the two methods.

Results

There was a significant but moderate correlation between LTM and FEBM (r = 0.309, P < .0001). LTM was consistently higher than FEBM, with an average difference 13.98 kg (95% confidence interval -5.90 to 33.86 kg), and the difference strongly correlated with LTM (r = 0.781, P < .0001). By multivariable linear regression analysis, LTM and residual renal function were independent predictors of the LTM-FEBM difference. Where the measurements were repeated in 12 months, there was no significant correlation between ∆LTM and ∆FEBM (r = -0.031, P = .799).

Conclusion

There is a significant difference between LTM and FFBM. This discrepancy correlated with LTM and residual renal function, highlighting the limitations of FFBM in assessing skeletal muscle mass.

Correlation of physical function and physical activity with muscle mass measured with computed tomography in adult hemodialysis patients

Introduction

Background: muscle mass (MM) plays an important role in the physical function of hemodialysis patients; however, muscle mass measurement can be unreliable and expensive. In contrast, the measurement of physical function (PF) is simple and inexpensive and may serve as an alternative. The aim of this study was to correlate the measurement of MM by computed tomography (CT) with physical function measurements and physical activity (PA) levels in HD patients. Methods: this was a cross-sectional study that included 38 HD patients from a single HD clinic. Each participant had a CT scan to measure mid-thigh muscle mass. Physical function tests were assessed using the six-minute walk test (SMWT), handgrip strength (HGS) test, 5 x sit-to-stand test (STS5), timed up and go test (TUGT) and Short Physical Performance Battery (SPPB), while physical activity levels were measured using the Godin-Shephard leisure-time physical activity questionnaire. Correlation analysis was used to examine the relationship between variables. Results: handgrip strength was strongly positively correlated with thigh muscle area (r = 0.656, p ≤ 0.001) and weakly correlated with arm muscle area (r = 0.396, p = 0.002), SMWT (r = 0.373, p = 0.004), SPPB (r = 0.269, p = 0.041) and physical activity (r = 0.323, p = 0.013). There was also a trend for an inverse correlation between handgrip strenght and TUGT (r = -0.235, p = 0.076). Positive correlations were found between the thigh muscle area and the SPPB (r = 0.339, p = 0.009) and PA (r = 0.293, p = 0.025), while there was a trend for an inverse correlation between thigh muscle area and STS5 (r = -0.256, p = 0.052). Conclusion: several measures of PF and strenght were correlated with objectives measurements of MM, thus provide options for low-cost measurements related to muscle mass.

Modified creatinine index as a marker of skeletal muscle mass in peritoneal dialysis patients

Background

Sarcopenia is common in peritoneal dialysis (PD) patients. Modified creatinine index (MCrI) by the Canaud's formula and single-pool Kt/V value is an accurate surrogate marker for muscle mass in hemodialysis patients. However, the method of calculation and validity of MCrI has not been tested in PD.

Methods

In the exploratory cohort, we studied 138 consecutive patients converted from PD to hemodialysis. Their MCrI during PD, calculated by the Canaud's formula with total weekly Kt/V, and the conventional MCrI after conversion to HD, were compared by the Bland-Altman method. Their correlation with muscle mass as determined by bioimpedance spectroscopy and creatinine kinetic methods was explored. The result was then validated in a second cohort of 605 incident PD patients.

Results

In the exploratory cohort, the average bias of computing MCrI during PD and hemodialysis was 0.758 mg/kg/day (95%CI -4.356 to 5.873 mg/kg/day). The MCrI during PD significantly correlated with the muscle mass by creatinine kinetics (r = .684, P < .0001) and by bioimpedance spectroscopy (r = .641, P < .0001), but not with protein nitrogen appearance, overhydration, or adipose tissue mass, and the result was similar in the validation cohort. For incident PD patients, MCrI quartile was significantly associated with the risk of death from all cause in 12 months (Gray's test, P = .013) but not conversion to chronic hemodialysis (P = .14).

Conclusion

In PD patients, MCrI computed by the Canaud's formula and total weekly Kt/V is a simple and reliable marker of skeletal muscle mass and may serve as a short-term prognostic indicator.

Effect of low muscle mass on total mortality related to metabolic disease in chronic kidney disease patients

Low muscle mass is a risk factor for mortality in patients with chronic kidney disease (CKD). However, it is not clear to what extent low muscle mass contributes to this risk, either independently or in combination with metabolic abnormalities and frailty. This study used data from the National Health and Nutrition Examination Survey 1999-2006 and 2011-2018. Low muscle mass was defined as Appendicular Skeletal Mass Index < 7 kg/m2 in men or < 5.5 kg/m2 in women. The follow-up duration was from the first anthropometric and clinical measurements to death or the last follow-up. This study enrolled 2072 patients with CKD. Low muscle mass was associated with a lower risk of metabolic abnormalities, but was associated with an elevated mortality risk. Conversely, central obesity was associated with a higher likelihood of metabolic abnormalities and frailty, yet showed no significant association with mortality risk. Subsequently conducted mediation analysis indicated that the effect of low muscle mass on mortality was direct, not mediated by frailty and metabolic abnormalities. In spite of the inverse relationship between low muscle mass and metabolic abnormalities, low muscle mass are directly associated with an increased risk of all-cause mortality. Low muscle mass may directly contribute to mortality in patients with CKD, independent of metabolic abnormalities and frailty in these patients.

Impact of high fat and low lean mass phenotype on bone mineral content: A cross-sectional study of Chinese adolescent population

BACKGROUND AND OBJECTIVE

Research on body composition phenotypes and bone health in adolescents is limited. Hence, this study aimed to analyze the relationship between different body composition phenotypes, bone mineral content, and bone metabolism markers in Chinese adolescents.

METHODS

In this cross-sectional study, 1852 adolescents aged 12 to 18 years were selected from six schools in Yinchuan City between 2017 and 2020 using stratified cluster random sampling. The participant's body composition and bone mineral content (BMC) were measured using bioelectrical impedance analysis (BIA). Serum bone metabolic markers (OC, CTX, and Ca) were measured. Based on their FMI and LMI, individuals were categorized into four body composition phenotypes: low fat mass-low lean mass (LFMI-LLMI), low fat mass-high lean mass (LFMI-HLMI), high fat mass-high lean mass (HFMI-HLMI), high fat mass-low lean mass (HFMI-LLMI).

RESULTS

There was a statistically significant difference between the four different body composition phenotypes with BMC, CTX and Ca in boys (all P < 0.05), similar conclusions were found in girls, except the OC and CTX. After adjusting for age, gender, smoking, drinking, and others, compared with the LFMI-HLMI reference group, the two high FMI groups (HFMI-LLMI and HFMI-HLMI) had a greater negative correlation with BMC, while the low BMC risk of the HFMI-LLMI group was the highest (OR = 33.28; 95%CI: 11.12-99.63; P < 0.001). The correlation between BMC of different body composition phenotypes in boys was greater than that in girls. HFMI-HLMI is a risk phenotype negatively associated with Ca content (β = -0.12; 95%CI: -0.19 to -0.04; P < 0.05). Regardless of body composition level, BMC was always negatively correlated with fat mass (LLMI: β = -0.27; 95%CI: -0.32-0.21; HLMI: β = -0.52, 95%CI: -0.65-0.40) and positively correlated with lean mass (LFMI: β =0.24; 95%CI: 0.20-0.28; HFMI: β =0.23, 95%CI:0.13-0.33) (all P < 0.001). The fat mass showed different correlations with OC and CTX in girls and boys based on LLMI or HLMI (all P < 0.05).

CONCLUSION

HFMI-LLMI is a risk phenotype of low BMC in Chinese adolescents, and the relationship between fat mass and bone metabolism markers is affected by lean body mass and gender.

Effects of additional physical exercise on the nutritional status and disease progression during the low-protein diet in Chronic Kidney Disease Patients: a systematic review and meta-analysis

Low-protein diet (LPD) is the core of dietary and nutritional therapy for non-dialysis chronic kidney disease (CKD) patients. In addition, physical exercise could prevent and treat various illnesses and chronic diseases. The objective of the study was to search for and appraise evidence on the effect of additional physical exercise on patients' nutritional status and indicators of disease progression when compared with the LPD alone. PubMed Central, Embase, Cochrane, and Web of Knowledge for randomized controlled trials (published between January 1, 1956 and May 17, 2023) were searched. A total of 8698 identified studies, 9 were eligible and were included in our analysis (N = 250 participants). Compared with the LPD alone, additional physical exercise reduced serum creatinine by a mean of -0.21 mg/dL (95% CI -0.39 to -0.03) in CKD patients. Similarly, blood pressure decreased after physical exercise, with systolic blood pressure decreasing by -7.05 mm Hg (95% CI -13.13 to -0.96) and diastolic blood pressure decreasing by -5.31 mm Hg (95% CI -7.99 to -2.62). Subgroup analyses revealed that resistance exercise (RE) was effective in decreasing estimated glomerular filtration rate (eGFR) of -1.71 mL/min per 1.73 m² (95% CI -3.29 to -0.14). In addition, the VO2peak increasing by 2.41 mL/kg/min (95% CI 0.13 to 4.70) when physical exercise was continued for 24 weeks. The above results suggest that the LPD with additional physical exercise care is more beneficial for patients with CKD.

Impact of Serum Creatinine- and Cystatin C-Based Sarcopenia Index on Renal Outcomes in Non-Dialysis-Dependent Chronic Kidney Disease Patients: Results From the KNOW-CKD Study

OBJECTIVE

To evaluate the impact of the serum creatinine- and cystatin C-based new sarcopenia index (SI) on renal outcomes in non-dialysis-dependent patients with chronic kidney disease (CKD).

METHODS

In this observational Korean Cohort Study for Outcome in Patients With CKD (KNOW-CKD), 1957 patients with CKD stage 1 to stage 4 were analyzed from 2011 to 2019. Men and women were separately assigned to quartile groups according to their SI. The primary outcome was a composite renal outcome consisting of 50% reduction in estimated glomerular filtration rate or end-stage kidney disease. With use of Fine and Gray subdistribution hazard models, the association between the SI and the primary outcome was analyzed.

RESULTS

During a median follow-up of 6.0 (4.2 to 7.7) years, the primary composite renal outcome occurred in 528 (28.6%) patients within a median of 3.0 (1.8 to 5.0) years. In unadjusted and adjusted models, lower SI groups had a poor primary outcome compared with the highest group (quartile 4). The hazard ratios for quartiles 1, 2, and 3 compared with quartile 4 in the fully adjusted model were 4.47 (95% CI, 3.05 to 6.56; P<.001), 3.08 (95% CI, 2.13 to 4.48; P<.001), and 2.09 (95% CI, 1.45 to 3.01; P<.001), respectively. Restricted cubic spline regression analyses found a relatively inverse linear relationship between the SI and the composite renal outcome.

CONCLUSION

The new SI is an independent predictor of renal outcomes. A low SI is associated with poor renal outcome.

Predictors of Skeletal Muscle Index for Patients Treated With Hemodialysis

OBJECTIVE

There is an increased risk of skeletal muscle mass (SMM) loss among patients with stage 5 chronic kidney disease treated with maintenance hemodialysis (MHD). The reduced SMM considerably influences the development of protein-energy wasting (PEW). Patients who develop PEW have higher hospitalization and mortality rates than those without PEW. This study determined if key variables could predict SMM Index (SMM adjusted for height) in patients receiving MHD.

METHODS

We conducted a secondary analysis of cross-sectional data obtained from the Rutgers Nutrition and Kidney Database (n = 178). Data were used to calculate both SMM and SMM Index. Univariate and multiple linear regression models explored the relationship between SMM Index and the following variables: serum albumin, urea clearance normalized treatment ratio, normalized protein catabolic rate, serum creatinine, and urea reduction ratio (URR).

RESULTS

Most participants were Black/African American (82.9%), male (59.1%), and obese (39%), with a mean age of 55.9 ± 11.9 years. The median Subjective Global Assessment score was 5, indicating a lower risk of malnutrition. Participants had a mean SMM of 26.4 kg and a median SMM Index of 8.9 kg/m2. Univariate regression modeling found URR to be a significant predictor of SMM Index, with increases in the percentage of URR predicting lower SMM Index values. The adjusted regression modeling found similar results, with increases in URR percentage predicting declines in SMM Index.

CONCLUSION

This study found that URR was a predictor of SMM Index in patients receiving MHD. Further research is required to explore these relationships and provide clinicians with a more extensive array of tools to recognize early signs of SMM loss to prevent the progression of PEW.

A Prospective Cohort Study Evaluating Impact of Sarcopenia on Hospitalization in Patients on Continuous Ambulatory Peritoneal Dialysis

Data regarding the association of sarcopenia with hospitalization has led to inconclusive results in patients undergoing dialysis. The main goal of this research was to investigate the association between sarcopenia and hospitalization in Chinese individuals on continuous ambulatory peritoneal dialysis (CAPD). Eligible patients on CAPD were prospectively included, and followed up for 48 weeks in our PD center. Sarcopenia was identified utilizing the criteria set by the Asian Working Group on Sarcopenia in 2019 (AWGS 2019). Participants were categorized into sarcopenia (non-severe sarcopenia + severe sarcopenia) and non-sarcopenia groups. The primary outcome was all-cause hospitalization during the 48-week follow-up period. Association of sarcopenia with all-cause hospitalization was examined by employing multivariate logistic regression models. The risk of cumulative incidence of hospitalization in the 48-week follow-up was estimated using relative risk (RR and 95% CI). The cumulative hospitalization time and frequency at the end of 48-week follow-up were described as categorical variables, and compared by χ2 test or fisher's exact test as appropriate. Subgroup and sensitivity analyses were also conducted to examine whether the potential association between sarcopenia and hospitalization was modified. A total of 220 patients on CAPD (5 of whom were lost in follow-up) were included. Prevalences of total sarcopenia and severe sarcopenia were 54.1% (119/220) and 28.2% (62/220) according to AWGS 2019, respectively. A total of 113 (51.4%) participants were hospitalized during the 48-week follow-up period, of which, the sarcopenia group was 65.5% (78/119) and the non-sarcopenia group was 34.7% (35/101), with an estimated RR of 1.90 (95%CI 1.43-2.52). The cumulative hospitalization time and frequency between sarcopenia and non-sarcopenia groups were significantly different (both P < 0.001). Participants with sarcopenia (OR = 3.21, 95%CI 1.75-5.87, P < 0.001), non-severe sarcopenia (OR = 2.84, 95%CI 1.39-5.82, P = 0.004), and severe sarcopenia (OR = 3.66, 95%CI 1.68-8.00, P = 0.001) demonstrated a significant association with all-cause hospitalization compared to individuals in non-sarcopenia group in the 48-week follow-up. Moreover, participants in subgroups (male or female; < 60 or ≥ 60 years) diagnosed with sarcopenia, as per AWGS 2019, were at considerably high risk for hospitalization compared to those with non-sarcopenia. In sensitivity analyses, excluding participants lost in the follow-up, the relationships between sarcopenia and hospitalization (sarcopenia vs. non-sarcopenia; severe sarcopenia/non-severe sarcopenia vs. non-sarcopenia) were consistent. This research involving Chinese patients on CAPD demonstrated a significant association between sarcopenia and incident hospitalization, thereby emphasizing the importance of monitoring sarcopenia health in this population.

Phase Angle as Surrogate Marker of Muscle Weakness in Kidney Transplant Candidates Referred to Prehabilitation

Phase angle (PhA), a marker of nutritional status obtained by bioelectrical impedance analysis (BIA), is associated with the integrity of cell membranes. Damage to muscle fiber membranes can impact muscle strength, which is related to adverse outcomes in adults with advanced chronic kidney disease (CKD). The main objective of this study was to determine the usefulness of the PhA in identifying muscle weakness in candidates for kidney transplants (KTs). Secondly, it aimed to examine the associations of PhA with other parameters of body composition, exercise performance, and muscle structure. Sensitivity, specificity, and area under the receiver operating characteristics curve were used to evaluate the PhA (index test) as a biomarker of muscle weakness. Muscle strength was estimated with maximal voluntary isometric contraction of the quadriceps (MVCI-Q) of the dominant side. Muscle weakness was defined as MVIC-Q < 40% of body weight. A total of 119 patients were evaluated (mean age 63.7 years, 75.6% men). A phase angle cut-off of 5.1° was identified to classify men with a higher likelihood of having low muscle strength in upper limbs (MVIC-Q 40% of their body weight). Male KT candidates with PhA < 5.1° had poorer exercise capacity, lower muscle strength, less muscle mass, and smaller muscle size. A PhA < 5.1° was significantly associated with an eight-fold higher muscle weakness risk (OR = 8.2, 95%CI 2.3-29.2) in a binary regression model adjusted by age, frailty, and hydration status. Remarkably, PhA is an easily obtainable objective parameter in CKD patients, requiring no volitional effort from the individual. The associations of PhA with aerobic capacity, physical activity, muscle mass, and muscle size underscore its clinical relevance and potential utility in the comprehensive evaluation of these patients.

Beyond sarcopenia: frailty in chronic haemodialysis patients

Background

Frailty, characterized by vulnerability, reduced reserves and increased susceptibility to severe events, is a significant concern in chronic haemodialysis (HD) patients. Sarcopenia, corresponding to the progressive loss of muscle mass and strength, may contribute to frailty by reducing functional capacity, mobility and autonomy. However, consensus lacks on the optimal bedside frailty index for chronic HD patients. This study investigated the influence of frailty on chronic HD patient survival and explored the associated factors.

Methods

A total of 135 patients were enrolled from January to April 2019 and then followed up prospectively until April 2022. At inclusion, frailty was assessed by the Timed Up and Go (TUG) and Short Physical Performance Battery (SPPB) tests including gait speed, standing balance and lower limb muscle strength.

Results

From a total of 114 prevalent chronic HD patients (66% men, age 67.6 ± 15.1 years), 30 died during the follow-up period of 23.7 months (range 16.8-34.3). Deceased patients were older, had more comorbidities and a higher sarcopenia prevalence (P < .05). The TUG and SPPB test scores were significantly reduced in patients who had died [SPPB total score: 7.2 ± 3.3 versus 9.4 ± 2.5; TUG time 8.7 ± 5.8 versus 13.8 ± 10.5 (P < .05)]. Multivariate analysis showed that a higher SPPB score (total value >9) was associated with a lower mortality risk [hazard ratio 0.83 (95% confidence interval 0.74-0.92); P < .03). Each component of the SPPB test was also associated with mortality in univariate analysis, but only the SPPB balance test remained protective against mortality in multivariate analysis. Older age, lower handgrip strength and lower protein catabolic rate were associated with SPPB total scores <9, SPPB balance score and TUG time >10 s.

Conclusions

Screening for frailty is crucial in chronic HD patients, and incorporating SPPB, especially the balance test, provides valuable insights. Diminished muscle strength and inadequate protein intake negatively influence the SPPB score and balance in chronic HD patients. Effective identification and management of frailty can therefore improve outcomes.

CLINICAL TRIAL REGISTRATION ClinicalTrialsgov

NCT03845452.

Prevalence and risk factors of sarcopenia in patients on maintenance hemodialysis: a retrospective cohort study

BACKGROUND

This study aimed to explore the prevalence and related risk factors of sarcopenia in patients on maintenance hemodialysis (MHD).

METHODS

This cohort study enrolled 165 patients on MHD. The patients were divided into sarcopenia and non-sarcopenia groups based on the presence of sarcopenia or not. Sarcopenia was diagnosed according to the consensus of the Asian Sarcopenia Working Group that considers reduced muscle mass and decreased muscle strength (19). The muscle mass was measured using the multi-frequency bioelectrical impedance (Inbody260) and skeletal muscle index (SMI) was used: <7.0 kg/m2 (male); <5.7 kg/m2 (female) - with muscle mass reduction. The electronic grip dynamometer was used for measuring dominant handgrip strength (HGS) to reflect muscle strength. Male patients with HGS < 28 kg and female patients with HGS < 18 kg were considered with a decrease in muscle strength. The demographic characteristics, laboratory indexes, anthropometrical measurements, body compositions, and InBody score were compared between groups. The multivariate logistic regression was used to explore the risk factors for sarcopenia.

RESULTS

Of the 165 patients on MHD, 36 had sarcopenia, and the prevalence was 21.82%. Patients in the sarcopenia group had higher ages and lower body mass index, serum albumin level, circumference of waist, hip, and biceps, handgrip strength, total water content, protein inorganic salt concentrations, skeletal muscle mass, basal metabolic rate, obesity degree, SMI, and body fat content. The multivariate logistic regression showed that age, waist circumference, handgrip strength, and InBody score were influencing factors for sarcopenia in patients on hemodialysis.

CONCLUSION

The prevalence of sarcopenia was high in patients on MHD. Higher age, lower waist circumference, lower handgrip strength, and lower InBody score were independent risk factors for sarcopenia in such patients.

Novel equations incorporating the sarcopenia index based on serum creatinine and cystatin C to predict appendicular skeletal muscle mass in patients with nondialysis CKD

BACKGROUND & AIMS

Skeletal muscle mass measurements are important for customizing nutritional strategies for patients with chronic kidney disease (CKD). The serum creatinine-to-cystatin C ratio (Cr/CysC) is a potential indicator of sarcopenia. We developed simple equations to predict the appendicular skeletal muscle mass (ASM) of patients with CKD using readily available parameters and Cr/CysC.

METHODS

Overall, 573 patients with nondialysis CKD stages 3-5 were included for developing and validating the equations. The participants were randomly divided into development and validation groups in a 2:1 ratio. ASM was measured using the Body Composition Monitor (BCM), a multifrequency bioelectrical impedance spectroscopy device. The height, weight, anthropometric data, and handgrip strength (HGS) of the participants were obtained. Equations were generated using stepwise multiple linear regression models. The prognostic significance of the predicted ASM was evaluated in a CKD registry comprising 1043 patients.

RESULTS

The optimal equation without anthropometric data and HGS (Equation 1) was as follows: ASM (kg) = -7.949 - 0.049 × Age (years) - 2.213 × Woman + 0.090 × Height (cm) + 0.210 × Weight (kg) + 1.141 × Cr/CysC. The modified equation (Equation 2) with anthropometric data and HGS was as follows: ASM (kg) = -4.468 - 0.050 × Age (years) - 2.285 × Woman+ 0.079 × Height (cm) + 0.228 × Weight (kg) - 0.127 × Mid-arm muscular circumference (cm) + 1.127 × Cr/CysC. Both equations exhibited strong correlations with the ASM measured via BCM in the validation cohort (r = 0.944 and 0.943 for Equations 1 and 2, respectively) with minimal bias. When Equation 1 was applied to the CKD registry, the estimated ASM index (ASM/Height2) significantly predicted overall mortality over a median of 54 months.

CONCLUSIONS

Novel ASM equations offer a simple method for predicting skeletal muscle mass and can provide valuable prognostic information regarding patients with nondialysis CKD.

Making the invisible visible: imaging techniques for assessing muscle mass and muscle quality in chronic kidney disease

Muscle wasting and low muscle mass are prominent features of protein energy wasting (PEW), sarcopenia and sarcopenic obesity in patients with chronic kidney disease (CKD). In addition, muscle wasting is associated with low muscle strength, impaired muscle function and adverse clinical outcomes such as low quality of life, hospitalizations and increased mortality. While assessment of muscle mass is well justified, the assessment of skeletal muscle should go beyond quantity. Imaging techniques provide the means for non-invasive, comprehensive, in-depth assessment of the quality of the muscle such as the infiltration of ectopic fat. These techniques include computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Dual energy X-ray absorptiometry is also an imaging technique, but one that only provides quantitative and not qualitative data on muscle. The main advantage of imaging techniques compared with other methods such as bioelectrical impedance analysis and anthropometry is that they offer higher precision and accuracy. On the other hand, the higher cost for acquiring and maintaining the imaging equipment, especially CT and MRI, makes these less-used options and available mostly for research purposes. In the field of CKD and end-stage kidney disease (ESKD), imaging techniques are gaining attention for evaluating muscle quantity and more recently muscle fat infiltration. This review describes the potential of these techniques in CKD and ESKD settings for muscle assessment beyond that of muscle quantity.

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.

Concordance between muscle mass assessed by bioelectrical impedance analysis and by muscle ultrasound: a cross-sectional study in a cohort of patients on chronic hemodialysis

BACKGROUND

Sarcopenia is a common problem in hemodialysis (HD) patients, and it is diagnosed by low muscle mass, strength and/or low physical performance. Muscle ultrasound (US) is a non-invasive portable tool that might be used for assessment of muscle mass. The aim of the current study was to investigate the concordance between muscle US and bioelectrical impedance analysis (BIA) in diagnosis of sarcopenia in HD patients.

METHODS

This cross-sectional study included 41 HD patients. Sarcopenia was diagnosed according to the European Working Group on Sarcopenia in Older People (EWGSOP). The skeletal mass index was measured by BIA and the muscle strength was measured by handgrip strength. Muscle US was used to measure cross-sectional area (CSA) and thickness of quadriceps and biceps muscles.

RESULTS

The current study included 41 patients on HD (25 males), with a mean (SD) age of 44.18 (13.11) years and a median HD duration of 48 months. Sarcopenia was diagnosed in 58.5% of the patients. Patients with sarcopenia had significantly lower quadriceps muscle CSA than those without sarcopenia. The optimal cut-offs of quadriceps muscle CSA for both males and females for the diagnosis of sarcopenia were 2.96 and 2.92 cm2, respectively.

CONCLUSION

Sarcopenia is prevalent among Egyptian HD patients. US on quadriceps muscle CSA could be used for diagnosis of sarcopenia in these patients.

Reliability and validity of the Patient Generated Index (PGI) in patients with chronic kidney disease (CKD) on dialysis, a new approach to quality of life

PURPOSE

To evaluate the test-retest reliability and validity of the Patient Generated Index (PGI) in individuals with Chronic Kidney Disease (CDK) undergoing hemodialysis.

METHODS

Through a non-experimental study with repeated measures, PGI was applied twice to assess internal consistency and test-retest reliability. Correlations with the Kidney Disease Quality of Life Short Form (KDQOL-SF), the Human Activity Profile (HAP) questionnaire, the Social Participation Scale, and the Glittre ADL Test were used.

RESULTS

91 individuals with CKD were evaluated. There was high reliability for the PGI (ICC= 0.97) PGI correlated with KQDOL - SF in Functional Capacity r = 0.38 (p < 0.001), Emotional Well-Being r = 0.31 (p = 0.003), Social Aspect r = 0.22 (p = 0.036), Emotional Function r = 0.22 (p = 0.038) and Effect of Kidney Disease r = 0.21 (p = 0.042), and Physical scores r = 0.24 (p = 0.021)), Mental r = 0.21 (p = 0.05) and General r = 0.22 (p = 0.037) summarized. There was a significant correlation between PGI and HAP r = 0.40 (p < 0.001) and the Social Participation Scale r = -0.36 (p < 0.001). There was no correlation between the PGI and Glittre ADL scores r = 0.12 (p = 0.247).

CONCLUSION

In adults receiving hemodialysis, the PGI proved to be an accurate and reliable instrument for the assessment of the quality of life from the perspective of the patient.IMPLICATIONS FOR REHABILITATIONAlthough hemodialysis treatment is associated with increased survival and symptom control, there is a significant change in the patient's lifestyle.In order to provide a more focused view of the individual, the Patient Generated Index (PGI) was created to evaluate the quality of life.PGI is reliable and correlates with KQDOL - SF and the Social Participation Scale in this population.

Possible sarcopenia and risk of chronic kidney disease: a four-year follow-up study and Mendelian randomization analysis

INTRODUCTION

Chronic kidney disease (CKD) is a common risk factor for sarcopenia. However, whether sarcopenia increases the risk of CKD remains unclear. To investigate the longitudinal and causal associations between possible sarcopenia and CKD, this study was performed.

METHODS

Possible sarcopenia was defined according to the Asian Working Group for Sarcopenia in 2019. Participants aged ≥ 40 years were recruited from the baseline survey of the China Health and Retirement Longitudinal Study and followed up for four years. Binary logistic regression was used to evaluate the cross-sectional and longitudinal associations between possible sarcopenia, low muscle strength, low physical performance and CKD. Propensity score matching was used to balance the intergroup differences. Subgroup and interactive analyses were adopted to identify potential interactive effects. Mendelian Randomization analysis was used to assess the causal association between appendicular lean mass (ALM) and CKD.

RESULTS

After data cleansing, a total of 7296 participants were included in the baseline survey. In the cross-sectional analyses, the odds ratios (ORs) of prevalent CKD were 1.50 (95% CI = 1.23-1.84, p < 0.001) for possible sarcopenia, 1.37 (95% CI = 1.10-1.70, p < 0.01) for low muscle strength and 1.42 (95% CI = 1.16-1.74, p < 0.001) for low physical performance in the full models. No significant interaction effects of covariates were detected (all P for interaction > 0.05). After four years of follow-up, an increased risk of incident CKD was also observed in participants with possible sarcopenia (OR = 1.66, 95% CI = 1.13-2.44, p = 0.010) and low physical performance (OR = 1.69, 95% CI = 1.16-2.45, p = 0.006), but not in participants with low muscle strength (OR = 1.19, 95% CI = 0.75-1.88, p = 0.469). In the Mendelian Randomization analysis, the inverse variance weighted estimator showed that a 1-standard deviation increase of genetically predicted ALM was associated with a lower risk of CKD (OR = 0.92, 95% CI = 0.85-0.99, p = 0.035). All the sensitivity analyses supported the main findings.

CONCLUSIONS

Possible sarcopenia is an independent risk factor for CKD and may serve as a predictor of CKD for early identification and intervention.

Effect of osteosarcopenia on longitudinal mortality risk and chronic kidney disease progression in older adults

INTRODUCTION

Chronic kidney disease (CKD) causes a progressive loss of muscle and bone mass, which frequently overlap with and affect clinical outcomes. However, the impact of sarcopenia, low bone mineral density (BMD; osteopenia or osteoporosis), and osteosarcopenia (sarcopenia and low BMD) on CKD progression is yet to be determined. We aimed to address these issues in patients with CKD without kidney replacement therapy (KRT).

METHODS

This prospective cohort study included 251 outpatients aged ≥65 years with CKD without KRT enrolled in our hospital between June 2016 and March 2017. Sarcopenia was defined according to the 2014 criteria of the Asian Working Group for Sarcopenia (AWGS), and low BMD was defined as a T-score of ≤-1.0. The patients were divided into four groups: normal (no sarcopenia/normal BMD), only low BMD (no sarcopenia/low BMD), only sarcopenia (sarcopenia/normal BMD), and osteosarcopenia (sarcopenia/low BMD). The primary outcome was a composite of all-cause deaths, initiating KRT, and admissions owing to major adverse cardiovascular and cerebrovascular events (MACEs). The secondary outcome was a kidney composite outcome that included a 30 % reduction in creatinine-based estimated glomerular filtration rate (eGFR) and initiating KRT. The outcome risk was determined using the Cox regression models adjusted for potential confounders.

RESULTS

Median age (25th-75th percentile) and eGFR of the outpatients (35 % women) were 76 (69-81) years and 32.1 (20.8-41.7) ml/min/1.73 m2, respectively. During a median follow-up period of 5.2 years, there were 22 deaths, 117 30 % eGFR reductions, 48 KRTs, and 18 admissions owing to MACEs. The osteosarcopenia group rather than the only low BMD or only sarcopenia groups exhibited a higher risk of the primary (hazard ratio [HR]: 3.28, 95 % confidence interval [CI]: 1.52-7.08) and kidney composite (HR: 2.07, 95 % CI: 1.10-3.89) outcomes. Among the osteosarcopenia-related body compositions and physical functions, low handgrip strength (HGS) was strongly associated with a high risk of primary and kidney composite outcomes (HR: 2.44, 95 % CI: 1.46-4.08; HR: 1.48, 95 % CI: 0.97-2.24, respectively). The increase in HGS but not the body mass index, skeletal muscle mass index, or BMD was associated with lower risks of primary and kidney composite outcomes (HR: 0.93, 95 % CI: 0.89-0.98; HR: 0.96, 95 % CI: 0.92-0.99 per 1 kg, respectively).

CONCLUSIONS

Osteosarcopenia was associated with poor survival and kidney outcomes in older patients with CKD. Low HGS, which is common in patients with osteosarcopenia and CKD, was associated with increased mortality risk and kidney function decline. These findings can help the risk prediction and pathogenesis of the kidney-bone-muscle axis and improving muscle strength can help mitigate CKD progression.

Indoxyl sulfate inhibits muscle cell differentiation via Myf6/MRF4 and MYH2 downregulation

BACKGROUND

Chronic kidney disease (CKD) is associated with a significant decrease in muscle strength and mass, possibly related to muscle cell damage by uremic toxins. Here, we studied in vitro and in vivo the effect of indoxyl sulfate (IS), an indolic uremic toxin, on myoblast proliferation, differentiation and expression of myogenic regulatory factors (MRF)-myoblast determination protein 1 (MyoD1), myogenin (Myog), Myogenic Factor 5 (Myf5) and myogenic regulatory factor 4 (Myf6/MRF4)-and expression of myosin heavy chain, Myh2.

METHODS

C2C12 myoblasts were cultured in vitro and differentiated in myotubes for 7 days in the presence of IS at a uremic concentration of 200 µM. Myocytes morphology and differentiation was analyzed after hematoxylin-eosin staining. MRF genes' expression was studied using reverse transcription polymerase chain reaction in myocytes and 5/6th nephrectomized mice muscle. Myf6/MRF4 protein expression was studied using enzyme-linked immunosorbent assay; MYH2 protein expression was studied using western blotting. The role of Aryl Hydrocarbon Receptor (AHR)-the cell receptor of IS-was studied by adding an AHR inhibitor into the cell culture milieu.

RESULTS

In the presence of IS, the myotubes obtained were narrower and had fewer nuclei than control myotubes. The presence of IS during differentiation did not modify the gene expression of the MRFs Myf5, MyoD1 and Myog, but induced a decrease in expression of Myf6/MRF4 and MYH2 at the mRNA and the protein level. AHR inhibition by CH223191 did not reverse the decrease in Myf6/MRF4 mRNA expression induced by IS, which rules out the implication of the ARH genomic pathway. In 5/6th nephrectomized mice, the Myf6/MRF4 gene was down-regulated in striated muscles.

CONCLUSION

In conclusion, IS inhibits Myf6/MRF4 and MYH2 expression during differentiation of muscle cells, which could lead to a defect in myotube structure. Through these new mechanisms, IS could participate in muscle atrophy observed in CKD.

Development and validation of a nomogram model for predicting low muscle mass in patients undergoing hemodialysis

BACKGROUND

Muscle mass is important in determining patients' nutritional status. However, measurement of muscle mass requires special equipment that is inconvenient for clinical use. We aimed to develop and validate a nomogram model for predicting low muscle mass in patients undergoing hemodialysis (HD).

METHODS

A total of 346 patients undergoing HD were enrolled and randomly divided into a 70% training set and a 30% validation set. The training set was used to develop the nomogram model, and the validation set was used to validate the developed model. The performance of the nomogram was assessed using the receiver operating characteristic (ROC) curve, a calibration curve, and the Hosmer-Lemeshow test. A decision curve analysis (DCA) was used to evaluate the clinical practicality of the nomogram model.

RESULTS

Age, sex, body mass index (BMI), handgrip strength (HGS), and gait speed (GS) were included in the nomogram for predicting low skeletal muscle mass index (LSMI). The diagnostic nomogram model exhibited good discrimination with an area under the ROC curve (AUC) of 0.906 (95% CI, 0.862-0.940) in the training set and 0.917 (95% CI, 0.846-0.962) in the validation set. The calibration analysis also showed excellent results. The nomogram demonstrated a high net benefit in the clinical decision curve for both sets.

CONCLUSIONS

The prediction model included age, sex, BMI, HGS, and GS, and it can successfully predict the presence of LSMI in patients undergoing HD. This nomogram provides an accurate visual tool for medical staff for prediction, early intervention, and graded management.

Reserved gait capacity and mortality among patients undergoing hemodialysis

BACKGROUND

Patients undergoing hemodialysis (HD) have difficulty increasing their gait speed in daily life. The extent of the increase from the usual gait speed (UGS) to the maximum gait speed (MGS) is considered the reserved gait capacity (RGC). Little is known regarding the implications of RGC. This study aimed to investigate the association between RGC and all-cause mortality in patients undergoing HD.

METHODS

In this retrospective study, we assessed the usual and maximum 10-m walking speed of outpatients who underwent HD between October 2002 and August 2021. RGC was defined as the ratio of MGS to UGS. Patients were divided into three groups according to the tertiles of RGC (low, moderate and high). A Cox proportional hazards regression model was used to examine the association between RGC and all-cause mortality.

RESULTS

Of the 496 (median age 66.0 years; men 59%) participants, 186 patients died during the follow-up (incident ratio of 62.0 per 1000 person-years). The patients with moderate [hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.46-0.94] and high (HR 0.44, 95% CI 0.30-0.65) RGC had a lower risk of mortality than the low RGC group. Furthermore, even when restricted to a population with only UGS <1.0 m/s, the group with high RGC still had a lower risk of mortality than those with low RGC (HR 0.55, 95% CI 0.33-0.94).

CONCLUSIONS

Lower RGC was independently associated with an increased risk of all-cause mortality among patients on HD; high RGC had a survival advantage even with a slow UGS.

Dietary fatty acids intake and all-cause and cardiovascular mortality in patients on peritoneal dialysis

BACKGROUND & AIMS

The relationship between dietary fatty acids (FA) and clinical outcomes are relatively lacking in non-dialyzed and dialyzed chronic kidney disease (CKD) population, resulting in insufficient guide about the dietary FA intake in this population. In this study, we aimed to observe the association between the intake of total or different types of FA and all-cause and cardiovascular (CV) mortality in patients undergoing peritoneal dialysis (PD).

METHODS

This is a prospective cohort study with data retrospectively analyzed in 881 patients undergoing PD. Dietary FA intake measured by 3-day dietary records. The outcomes were defined as all-cause and CV death. Baseline FA intake and time-averaged FA intake were categorized by tertiles based on the distribution among the study population. We used univariate and multivariate Cox proportional regression models to determine the association between amounts and types of FA and all-cause and CV mortality.

RESULTS

During a median follow up of 45 months, 93 patients were still being maintained on PD, 467 had died, including 189 (40.5%) attributable to CV death. Compared to patients in the low tertile of total FA (TFA) intake at baseline group, the middle or/and high tertile groups were more likely to be male, younger, well-educated and better nutritional status (P < 0.05). At the baseline, no association was found between all-cause and CV death in either total or different types of FA after adjusting for nutritional variables. As for time-averaged analyses, the associations of TFA, saturated FA (SFA), monounsaturated FA (MUFA), ω-3 and ω-6 polyunsaturated FA (PUFA) and all-cause mortality were weakened after adjustment for laboratory and nutrients variables. However, PUFA independently reduced 5% of mortality even after adjustment for laboratory and nutrients variables [HR 0.95 (0.91, 0.99), P = 0.023], and the ratio of MUFA/PUFA was positively associated with the risk for all-cause mortality [HR 1.05 (1.01, 1.09), P = 0.008]. Furthermore, each 10% increase of the ratio of ω-6/ω-3 was only weakly associated with the risk for all-cause mortality [HR 1.02 (1.00, 1.04), P = 0.034]. As for CVD mortality, the impacts of total and each type of FA disappeared after adjustment for laboratory or nutrients variables.

CONCLUSIONS

Time-averaged PUFA intake was independently associated with a lower risk for all-cause mortality in our PD cohort, while the higher ratio of MUFA/PUFA and ω-6/ω-3 increased all-cause mortality. More observational and interventional researches are needed to determine these associations.

Handgrip strength and all-cause mortality in patients with chronic kidney disease: an updated systematic review and meta-analysis of cohort studies

OBJECTIVES

In observational studies, handgrip strength (HGS), a prognostic marker for healthy aging, has been associated with several chronic disease outcomes. The present systematic review and meta-analysis aimed to determine the quantitative relationship between HGS and the risk of all-cause mortality in patients with chronic kidney disease (CKD).

METHODS

Search PubMed, Embase, and Web of Science databases. The search was performed from inception to July 20, 2022, and the search was updated in February 2023. Cohort studies were included exploring the relationship between handgrip strength and the risk of all-cause mortality in patients with chronic kidney disease. Effect estimates and 95% confidence intervals (95% CI) were extracted from the studies to perform pooling. The quality of included studies was assessed using the Newcastle-Ottawa scale. We evaluated the overall certainty of evidence using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE).

RESULTS

This systematic review included 28 articles. A random-effects meta-analysis that included 16,106 patients with CKD showed that participants with lower HGS had an increased mortality risk of 96.1% compared to higher HGS (HR: 1.961; 95% CI 1.591-2.415) (GRADE: very low). Moreover, this association was independent of baseline mean age and follow-up time. In 2,967 patients with CKD, a random-effects model-based meta-analysis showed that for each 1-unit increase in HGS, the risk of death in patients with CKD was reduced by 3.9% (HR: 0.961; 95% CI 0.949-0.974) (GRADE: moderate).

CONCLUSIONS

In patients with CKD, better HGS is associated with a lower risk of all-cause mortality. This study supports using HGS as a strong predictor of mortality in this population.

All you need to know about sarcopenia: a short guide for an internal medicine physician in questions and answers

Sarcopenia is associated with social, economic, and individual burdens, including loss of independence, poor quality of life, and disability. In a short period of time, ideas about sarcopenia transformed from geriatric syndrome to disease. Initially, sarcopenia was considered in the context of gradual age-related deterioration in the functioning of all physiological systems. Over the years, it became clear that it can develop a second time, as a consequence of various diseases and pathological conditions.

To date, there have been no generally accepted diagnostic criteria for sarcopenia. There are several tests and tools available for screening sarcopenia, the choice of which depends on physical capabilities of the patient, capabilities of the medical institution, and the purpose for which it is detected (research or clinical practice).

From the point of view of human health, sarcopenia increases the risk of falls and fractures; impairs the ability to perform daily activities; is associated with the progression of major diseases and cognitive impairments; leads to movement disorders; contributes to a decrease in the quality of life, loss of independence or a need for long-term care. The presence of sarcopenia increases both the risk of hospitalization and hospitalization costs.

The aim of the literature review is to provide an analysis of up-to-date information on the causes, pathogenesis, screening, diagnosis, treatment, and consequences of sarcopenia, myosteatosis, and sarcopenic obesity. The search for literature containing information on relevant studies was conducted in PubMed and Google Scholar by the following keywords: sarcopenia, dynapenia, myosteatosis, sarcopenic obesity, nutritional status, malnutrition.

The Use of Practical Measures to Determine Body Composition of Older People

Background

Older adults frequently experience body composition changes-decreased lean body mass (LBM) and bone mineral content (BMC), along with increased body fat mass (FM)-which affect their health and independence. However, the need for standard complex and costly imaging modalities could delay the detection of these changes and retard treatment effectiveness. Thus, this study explored the ability of practical measures, including simple muscle strength tests and demographic data, to determine the body composition of older adults.

Methods

Participants (n = 111, with an average age of 77 years old) were cross-sectionally assessed for the outcomes of the study, including upper limb loading during a seated push-up test (ULL-SPUT), hand grip (HG) strength test and body composition.

Results

The ULL-SPUT significantly correlated with body composition (r or rs, = 0.370-0.781; P < 0.05), particularly for female participants and was higher than that found for the HG strength test (rs = 0.340-0.614; P < 0.05). The ULL-SPUT and HG strength test, along with gender and body mass index (BMI), could accurately determine the LBM and BMC of the participants up to 82%.

Conclusion

The ULL-SPUT along with gender and BMI can be used as a practical strategy to detect the LBM and BMC of older adults in various settings. Such a strategy would facilitate timely managements (i.e. standard confirmation or appropriate interventions) in various settings.

Analysis of the rate of force development reveals high neuromuscular fatigability in elderly patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) induces muscle wasting and a reduction in the maximum voluntary force (MVF). Little is known about the neuromuscular fatigability in CKD patients, defined as the reduction of muscle force capacities during exercise. Neuromuscular fatigability is a crucial physical parameter of the daily living. The quantification of explosive force has been shown to be a sensitive means to assess neuromuscular fatigability. Thus, our study used explosive force estimates to assess neuromuscular fatigability in elderly CKD patients.

METHODS

Inclusion criteria for CKD patients were age ≥ 60 years old and glomerular filtration rate (GFR) < 45 mL/min/1.73 m2 not on dialysis, and those for controls were GFR > 60 mL/min/1.73 m2 , age and diabetes matched. The fatigability protocol focused on a handgrip task coupled with surface electromyography (sEMG). Scalars were extracted from the rate of force development (RFD): absolute and normalized time periods (50, 75, 100, 150 and 200 ms, RFD50 , RFD75 , RFD100 , RFD150 and RFD200 , respectively), peak RFD (RFDpeak in absolute; NRFDpeak normalized), time-to-peak RFD (t-RFDpeak ) and the relative force at RFDpeak (MVF-RFDpeak ). A statistical parametric mapping approach was performed on the force, impulse and RFD-time curves. The integrated sEMG with time at 0-30, 0-50, 0-100 and 0-200 ms time intervals relative to onset of sEMG activity was extracted and groups were compared separately for each sex.

RESULTS

The cohort of 159 individuals had a median age of 69 (9IQR ) years and body mass index was 27.6 (6.2IQR ) kg/m2 . Propensity-score-matched groups balanced CKD patients and controls by gender with 66 males and 34 females. In scalar analysis, CKD patients manifested a higher decrement than controls in the early phase of contraction, regarding the NRFDpeak (P = 0.009; η2 p  = 0.034) and RFD75 and RFD100 (for both P < 0.001; η2 p  = 0.068 and 0.064). The one-dimensional analysis confirmed that CKD males manifest higher and delayed neuromuscular fatigability, especially before 100 ms from onset of contraction. sEMG was lower in CKD patients than controls in the 0-100 ms (at rest: P = 0.049, Cohen's d = 0.458) and 0-200 ms (at rest: P = 0.016, Cohen's d = 0.496; during exercise: P = 0.006, Cohen's d = 0.421) time windows. Controls showed greater decrease of sEMG than CKD patients in the 0-30 ms (P = 0.020, Cohen's d = 0.533) and 0-50 ms (P = 0.010, Cohen's d = 0.640) time windows. As opposite to females, males showed almost the same differences between groups.

CONCLUSIONS

Our study is the first to show that CKD patients have higher fatigability than controls, which may be associated with an impaired motor-unit recruitment, highlighting a neural drive disturbance with CKD. Further studies are needed to confirm these findings.

GLIM in chronic kidney disease: What do we need to know?

The lack of consensus on diagnostic criteria for malnutrition has hampered developments in research and clinical practice pertaining to nutrition. This opinion paper describes the applicability and other aspects of using the Global Leadership Initiative on Malnutrition (GLIM) criteria for diagnosing malnutrition in patients with chronic kidney disease (CKD). We examine the purpose of GLIM, the particularities of CKD that can affect the nutritional and metabolic status and the diagnosis of malnutrition. In addition, we make an appraisal of previous studies that used GLIM in the context of CKD and discuss the value and relevance of using the GLIM criteria in patients with CKD.

Effect of oral nutritional supplementation combined with impedance vectors for dry weight adjustment on the nutritional status, hydration status and quality of life in patients on chronic hemodialysis: A pilot study

BACKGROUND & AIMS

Protein energy wasting frequently affect hemodialysis patients and contribute to the development of overhydration. The objective of this study was to assess the effect of oral nutritional supplementation (ONS) combined with bioelectrical vector analysis (BIVA) on the nutritional and hydration status and the quality of life (QoL) in hemodialysis (HD) patients.

METHODS

Thirty-two chronic HD patients were included in a 6-month randomized pilot study. Patients in SUPL group received a simultaneous intervention consisting of a personalized diet, 245 mL/d ONS and dry weight adjustment through BIVA. Patients in CON group received a personalized diet and dry weight adjustment by BIVA. Anthropometrical, biochemical, dietary, QoL, handgrip strength (HGS) and bioimpedance measurements were performed. Malnutrition Inflammation Score (MIS) was applied.

RESULTS

At the end of the intervention, moderate undernutrition decreased by 43.8% in SUPL group while in CON group, severe undernutrition increased by 13% (p < 0.04 between groups). In the adjusted covariance analysis, SUPL compared to CON group, increased HGS (Δ 2.8 Kg vs Δ -1.8 Kg, p = 0.003), serum albumin (Δ 0.29 g/dL vs Δ -0.03 g/dL, p = 0.04) and serum transferrin (Δ 4.7 mg/dL vs Δ -0.7 mg/dL, p = 0.0007). The increase in QoL was significantly higher in SUPL group. Dry weight was achieved in 100% of patients in SUPL and 95% in CON group.

CONCLUSIONS

ONS combined with BIVA for dry weight adjustment, improved nutritional status, QoL and achieved dry weight in HD patients.

Muscle fat infiltration in chronic kidney disease: a marker related to muscle quality, muscle strength and sarcopenia

Muscle fat infiltration (MFI) also known as myosteatosis refers to any deposit of lipids found in the skeletal muscle. MFI is preferably assessed by image-based methods like computed tomography (CT), magnetic resonance image (MRI) and ultrasound, normally from muscle groups located in the legs, arms and in the trunk. MFI is understood as a marker of muscle quality, where a muscle with higher fat deposition has lower contraction power and capacity to produce force per unit of muscle mass. This concept supports the hypothesis that a decrease in muscle strength is not always explained by a decrease in muscle mass, but also by other factors, including lipid deposition in the muscle. In the general population, MFI is associated with older age, physical inactivity and with insulin resistance and inflammation. In chronic kidney disease (CKD), MFI has been associated with a decrease in muscle strength and impaired muscle quality as well as with metabolic abnormalities, cardiovascular disease and increased mortality. Interventions aimed at reducing MFI in CKD are incipient, but it seems that guided exercise can ameliorate muscle quality in patients on hemodialysis. The aim of this narrative review about MFI in CKD is to draw attention to a still not often addressed complication in CKD. We conclude that more studies are warranted to investigate mechanisms and factors promoting MFI in CKD. Thus, clinical trials aimed at understanding the type, frequency and intensity of exercise that can diminish MFI and improve the clinical condition of the patients are needed.

From MIA to FIFA: The vicious matrix of frailty, inflammation, fluid overload and atherosclerosis in peritoneal dialysis

Cardiovascular disease (CVD) is a major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Two decades ago, the common co-existence of malnutrition and systemic inflammation PD patients with atherosclerosis and CVD led to the proposed terminology of 'malnutrition-inflammation-atherosclerosis (MIA) syndrome'. Although the importance of malnutrition is well accepted, frailty represents a more comprehensive assessment of the physical and functional capability of the patient and encompasses the contributions of sarcopenia (a key component of malnutrition), obesity, cardiopulmonary as well as neuropsychiatric impairment. In recent years, it is also increasingly recognized that fluid overload is not only the consequence but also play an important role in the pathogenesis of CVD. Moreover, fluid overload is closely linked with the systemic inflammatory status, presumably by gut oedema, gastrointestinal epithelial barrier dysfunction and leakage of bacterial fragments to the systemic circulation. There are now a wealth of published evidence to show intricate relations between frailty, inflammation, fluid overload and atherosclerotic disease in patients with chronic kidney disease (CKD) and those on PD, a phenomenon that we propose the term 'FIFA complex'. In this system, frailty and atherosclerotic disease may be regarded as two patient-oriented outcomes, while inflammation and fluid overload are two inter-connected pathogenic processes. However, there remain limited data on how the treatment of one component affect the others. It is also important to define how treatment of fluid overload affect the systemic inflammatory status and to develop effective anti-inflammatory strategies that could alleviate atherosclerotic disease and frailty.

Low-Plasma Insulin-Like Growth Factor-1 Associates With Increased Mortality in Chronic Kidney Disease Patients With Reduced Muscle Strength

OBJECTIVES

Chronic kidney disease (CKD) leads to metabolic and nutritional abnormalities including resistance to insulin-like growth factor-1 (IGF-1) action, and reduced muscle mass and strength. Low IGF-1 as well as low hand-grip muscle strength (HGS) are independent predictors of increased mortality in CKD patients.

METHODS

In 685 patients (CKD Stage 3-5, median age 58 years; 62% men), baseline measurements of IGF-1, HGS, subjective global assessment (SGA), lean body mass index (LBMI), and metabolic and inflammatory biomarkers potentially linked to IGF-1 were analyzed in relation to mortality during 5 years of follow-up. We compared survival in 4 groups with high or low (cut-offs defined by receiver operating characteristic curve analysis) levels of IGF-1 and HGS.

RESULTS

Patients with low IGF-1 were older; had lower BMI, HGS, and LBMI, were more likely to have diabetes, cardiovascular disease (CVD), and malnutrition (SGA >1); and had high-sensitivity C-reactive protein levels. During 5 years of follow-up, 208 patients died. The mortality rate was highest among patients with Low IGF-1 + Low HGS. In competing-risk regression analysis, Low IGF-1 + Low HGS was independently associated with 2.8 times higher all-cause mortality risk than Low IGF-1 + High HGS, after adjusting for Framingham's CVD risk score, presence of CVD, SGA, dialysis status, high-sensitivity C-reactive protein, albumin, LBMI, and sample time in freezer.

CONCLUSION

Low IGF-1 was associated with increased all-cause mortality in patients who also had low HGS but not in those with high HGS, suggesting that the association of IGF-1 with survival in CKD patients depends on nutritional status.

Age and sex differences in the effectiveness of intradialytic resistance training on muscle function

Previous research shows the beneficial effects of an intradialytic resistance training (IRT) on muscle function in haemodialysis patients. However, patients vary highly in their functional responses to IRT, may be due to effects of age and sex heterogeneities in adaptation. Therefore, the aim of this study was to investigate the degree to which the effects of IRT on the muscle function of haemodialysis patients vary by age and sex. We included 57 patients who completed a 12-week IRT (EXG) and 33 patients who received no IRT (CNG) during haemodialysis. Muscle function (MF) was assessed using dynamometry before and after a 12-week intervention and after a 12-week follow-up. After the 12-week intervention, we found a moderation effect of age in the relative (%) change (p = 0.011) and absolute (Δ) change (p = 0.027) of MF, and a moderation effect of sex in %MF (p = 0.001), but not in ΔMF (p = 0.069). Regarding patients' age, the change of MF was only significantly different between EXG and CNG patients aged 60-70 years (%MF, EXG: + 34.6%, CNG: - 20.1%, p < 0.001; ΔMF, EXG: + 44.4 N, CNG: - 22.1 N, p < 0.001). Regarding patients' sex, the change of MF was only significantly different between EXG and CNG female patients (%MF, EXG: + 23.9%, CNG: - 23.6%, p < 0.001). Age and sex did not significantly moderate changes in MF measures after 12 weeks of follow-up. We conclude that both age and sex of haemodialysis patients affect their functional response to IRT in the short term.Trial Registration: Intradialytic Resistance Training in Haemodialysis Patients (IRTHEP)-#NCT03511924, 30/04/2018, https://clinicaltrials.gov/ct2/show/NCT03511924 .

A Sarcopenia Index Derived from Malnutrition Parameters in Elderly Haemodialysis Patients

(1) Background: Persons with chronic kidney disease may have sarcopenia characterized by the loss of muscle mass and loss of muscle strength. However, EWGSOP2 criteria to diagnose sarcopenia are technically challenging, especially in elderly persons on hemodialysis. Sarcopenia may be associated with malnutrition. We aimed at defining a sarcopenia index derived from malnutrition parameters for use in elderly haemodialysis patients. (2) Methods: A retrospective study of 60 patients aged 75 to 95 years treated with chronic hemodialysis was conducted. Anthropometric and analytical variables, EWGSOP2 sarcopenia criteria and other nutrition-related variables were collected. Binomial logistic regressions were used to define the combination of anthropometric and nutritional parameters that best predict moderate or severe sarcopenia according to EWGSOP2, and performance for moderate and severe sarcopenia was assessed by the area under the curve (AUC) of receiver operating characteristic (ROC) curves. (3) Results: The combination of loss of strength, loss of muscle mass and low physical performance correlated with malnutrition. We developed regression-equation-related nutrition criteria that predicted moderate sarcopenia (elderly hemodialysis sarcopenia index-moderate, EHSI-M) and severe sarcopenia (EHSI-S) diagnosed according to EWGSOP2 with an AUC of 0.80 and 0.866, respectively. (4) Conclusions: There is a close relationship between nutrition and sarcopenia. The EHSI may identify EWGSOP2-diagnosed sarcopenia from easily accessible anthropometric and nutritional parameters.

Low Phase Angle Values Are Associated with Malnutrition according to the Global Leadership Initiative on Malnutrition Criteria in Kidney Transplant Candidates: Preliminary Assessment of Diagnostic Accuracy in the FRAILMar Study

Malnutrition has a negative impact on patients with chronic diseases and its early identification is a priority. The primary objective of this diagnostic accuracy study was to assess the performance of the phase angle (PhA), a bioimpedance analysis (BIA)-derived parameter, for malnutrition screening using the Global Leadership Initiative for Malnutrition (GLIM) criteria as the reference standard in patients with advanced chronic kidney disease (CKD) waiting for kidney transplantation (KT); criteria associated with low PhA in this population were also analyzed. Sensitivity, specificity, accuracy, positive and negative likelihood ratios, predictive values, and area under the receiver operating characteristic curve were calculated for PhA (index test) and compared with GLIM criteria (reference standard). Of 63 patients (62.9 years old; 76.2% men), 22 (34.9%) had malnutrition. The PhA threshold with the highest accuracy was ≤4.85° (sensitivity 72.7%, specificity 65.9%, and positive and negative likelihood ratios 2.13 and 0.41, respectively). A PhA ≤ 4.85° was associated with a 3.5-fold higher malnutrition risk (OR = 3.53 (CI95% 1.0-12.1)). Considering the GLIM criteria as the reference standard, a PhA ≤ 4.85° showed only fair validity for detecting malnutrition, and thus cannot be recommended as a stand-alone screening tool in this population.

Association between Urinary Creatinine Excretion and Hypothyroidism in Patients with Chronic Kidney Disease

While hypothyroidism increases serum creatinine (Cr) levels, it is uncertain whether the elevation is mediated via a decline in the glomerular filtration rate (GFR) or the reflection of enhanced Cr production from the muscles or both. In the present study, we explored an association between urinary Cr excretion rate (CER) and hypothyroidism. A total of 553 patients with chronic kidney disease were enrolled in a cross-sectional study. Multiple linear regression analysis was performed to explore the association between hypothyroidism and urinary CER. The mean urinary CER was 1.01 ± 0.38 g/day and 121 patients (22%) had hypothyroidism. The multiple linear regression analysis revealed explanatory variables with urinary CER, including age, sex, body mass index, 24 h Cr clearance (24hrCcr), and albumin while hypothyroidism was not considered an independent explanatory variable. In addition, scatter plot analysis with regression fit line representing the association between estimated GFR calculated using s-Cr (eGFRcre) and 24hrCcr revealed that eGFRcre and 24hrCcr had strong correlations with each other in hypothyroid patients as well as euthyroid patients. Collectively, hypothyroidism was not considered an independent explanatory variable for urinary CER in the present study and eGFRcre is a useful marker to evaluate kidney function regardless of the presence of hypothyroidism.

Low skeletal muscle mass is associated with mortality in kidney transplant recipients

Muscle wasting in chronic kidney disease is associated with increased cardiovascular events, morbidity, and mortality. However, whether pretransplantation skeletal muscle mass affects kidney transplantation (KT) outcomes has not been established. We analyzed 623 patients who underwent KT between 2004 and 2019. We measured the cross-sectional area of total skeletal muscle at the third lumbar vertebra level on pretransplantation computed tomography scan. The patients were grouped into low and normal skeletal muscle mass groups based on the sex-specific skeletal muscle mass index lowest quartile. During the entire follow-up period, 45 patients (7.2%) died and 56 patients (9.0%) experienced death-censored graft loss. Pretransplantation low skeletal muscle mass was independently associated with all-cause mortality (adjusted hazard ratio, 2.269; 95% confidence interval, 1.232-4.182). Low muscle mass was also associated with an increased risk of hospital readmission within 1 year after transplantation. Death-censored graft survival rates were comparable between the 2 groups. The low muscle group showed higher creatinine-based estimated glomerular filtration rates (eGFRs) than the normal muscle group. Although cystatin C-based eGFRs were measured in only one-third of patients, cystatin C-based eGFRs were comparable between the 2 groups. Pretransplantation low skeletal muscle mass index is associated with an increased risk of mortality and hospital readmission after KT.

Age, hemodialysis time, gait speed, but not mortality, are associated with muscle quality index in end-stage renal disease

BACKGROUND

The muscle quality index (MQI) has proven to be an interesting clinical measurement in hemodialysis (HD) patients. In clinical practice, its interpretation can be biased by fat mass (FM) distribution. This study aims to explore the arm MQI association with body composition, clinical factors, and mortality.

METHODS

It was analytical longitudinal and exploratory, that included patients from two-center, over 18 years old, of both genders in treatment by HD. The follow-up period was 32 months, and mortality was the clinical outcome. Demographical and clinical data were collected in the patient's medical records. Body composition was evaluated using octopolar multi-frequency bioelectrical impedance analysis (MF-BIA). Handgrip strength (HGS) was measured by a dynamometer and the time required to walk 3 m was applied to obtain gait speed. The baseline associations with MQI (HGS/arm muscle mass) were examined by multivariate linear regression. Cox regressions evaluated the associations with mortality.

RESULTS

A total of 97 patients in HD were included. Mean age was 50.93 ± 14.10 years, 71.13 % were male. Age (β = -0,096, p = 0.024), HD time (β = -0.023, p = 0.032), total skeletal muscle mass (β = -0.475, p < 0.001) were inversely associated with MQI and gait speed had a direct association with MQI (β = 8514, p = 0.002). The prevalence of mortality was 29.76 %, of which 37.29 % were men (p = 0.020). Low MQI was not associated with mortality (Hz = 0.80, CI95 % = 0.34; 1.91, p = 0.629).

CONCLUSION

The arm MQI was associated with an indicator of general functional capacity (gait speed), but was not associated with fat measures in baseline and mortality after 32 months of follow-up.

Using machine learning to detect sarcopenia from electronic health records

Introduction

Sarcopenia (low muscle mass and strength) causes dysmobility and loss of independence. Sarcopenia is often not directly coded or described in electronic health records (EHR). The objective was to improve sarcopenia detection using structured data from EHR.

Methods

Adults undergoing musculoskeletal testing (December 2017-March 2020) were classified as meeting sarcopenia thresholds for 0 (controls), ≥1 (Sarcopenia-1), or ≥2 (Sarcopenia-2) tests. Electronic health record diagnoses, medications, and laboratory testing were extracted from the Indiana Network for Patient Care. Five machine learning models were applied to EHR data for predicting sarcopenia.

Results

Of 1304 participants, 1055 were controls, 249 met Sarcopenia-1 and 76 met Sarcopenia-2. Sarcopenic participants were older, with higher fat mass, Charlson Comorbidity Index, and more chronic diseases. All models performed better for Sarcopenia-2 than Sarcopenia-1. The top performing models for Sarcopenia-1 were Logistic Regression [area under the curve (AUC) 71.59 (95% confidence interval [CI], 71.51-71.66)] and Multi-Layer Perceptron [AUC 71.48 (95%CI, 71.00-71.97)]. The top performing models for Sarcopenia-2 were Logistic Regression [AUC 91.44 (95%CI, 91.28-91.60)] and Support Vector Machine [AUC 90.81 (95%CI, 88.41-93.20)]. For the best Logistic Regression Model, important sarcopenia predictors included diabetes mellitus, digestive system complaints, signs and symptoms involving the nervous, musculoskeletal and respiratory systems, metabolic disorders, and kidney or urinary tract disorders. Opioids, corticosteroids, and antihyperlipidemic drugs were also more common among sarcopenic participants.

Conclusions

Applying machine learning models, sarcopenia can be predicted from structured data in EHR, which may be developed through future studies to facilitate large-scale early detection and intervention in clinical populations.