Prevalence of Sarcopenia and Its Impact on Cardiovascular Events and Mortality among Dialysis Patients: A Systematic Review and Meta-Analysis

Predictive value of creatinine-cystatin C ratio for mortality and technique failure in anuric peritoneal dialysis patients

OBJECTIVES

Both serum creatinine and cystatin C serve as dependable markers of renal function and have demonstrated a correlation with clinical outcomes in diverse conditions, particularly through the ratio of creatinine to cystatin C (Cr/CysC). Anuric patients undergoing peritoneal dialysis (PD) depend entirely on the clearance of peritoneal solutes. This research posits that the Cr/CysC ratio may predict all-cause mortality and technique failure in anuric PD patients.

METHODS

A cohort of 224 anuric PD patients was recruited from January 1, 2014, to December 31, 2019, with follow-up extending until December 31, 2023. The Cr/CysC ratio was computed by dividing the serum creatinine concentration by the cystatin C concentration obtained on the same day. We evaluated the relationship between the Cr/CysC ratio and patient survival, as well as technique failure, utilizing Cox regression and competing risk analyses.

RESULTS

The average age of the participants was 50.46 ± 12.63 years, with 99 individuals (44.2%) being male. Among all subjects, the Cr/CysC ratio was found to be 1.85 ± 0.56. After controlling for potential confounders, Cox proportional hazards models revealed that the Cr/CysC ratio was significantly linked to the risk of all-cause mortality and technique failure (HR = 0.330, 95% CI 0.124-0.881, p = 0.027; HR = 0.440, 95% CI 0.267-0.726, p = 0.002). Importantly, the significant associations observed in the Cox regression analysis persisted even after accounting for competing risks.

CONCLUSION

The Cr/CysC ratio at baseline was recognized as an independent predictor of all-cause mortality and technique failure in anuric PD patients.

Association of Muscle Radiodensity and Muscle Mass With Thoracic Aortic Calcification Progression in Dialysis Patients

BACKGROUND

Recent findings have spotlighted sarcopenia as a critical factor exacerbating cardiovascular risk in dialysis patients. However, no studies have investigated the relationship of muscle characteristics with thoracic aortic calcification (TAC). We explored whether skeletal muscle radiodensity (SMD) and skeletal muscle index (SMI) are associated with TAC in dialysis patients.

METHODS

In this study, 2517 dialysis patients (between January 2020 and June 2023) from four centres with chest computed tomography (CT) scans were analysed cross-sectionally. A cohort of 544 initial-dialysis patients (between January 2014 and December 2020) was followed for TAC progression. Chest CT images were used to assess SMD and SMI at the L1 level, as well as to measure the scores of TAC, including ascending TAC (ATAC), aortic arch calcification (AoAC) and descending TAC (DTAC). Multivariable linear regression models were employed to assess the effects of SMD and SMI on TAC and its progression. Restricted cubic spline was used to assess the potential non-linear relationships of SMD and SMI with TAC progression.

RESULTS

The mean (SD) age for the cross-sectional study was 54.8 (14.0) years, with males accounting for 58.2%. Over a mean (SD) follow-up duration of 3.45 (1.82) years, 85.7% showed TAC progression. Comparing the highest quartile of SMD to the lowest quartile, a significant inverse association was observed with TAC (β, -1.08 [-1.42 to -0.75]; p < 0.001); similar trends were noted for SMI (β, -0.42 [-0.74 to -0.10]; p = 0.011). SMD and SMI as continuous variables were also both significantly negatively correlated with TAC. In the longitudinal study, multivariable linear regression models revealed that an increase of 1 SD in SMD resulted in a decrease of 0.10 SD (95% CI, -0.17 to -0.02; p = 0.011) in TAC progression, and an increase of 1 SD in SMI resulted in a decrease of 0.12 SD (95% CI, -0.20 to -0.04; p = 0.003) in TAC progression. Restricted cubic spline models excluded non-linear trends for the relationships of SMD and SMI with TAC progression. The associations of SMD and SMI with DTAC were consistent with those observed for TAC, but neither showed a significant association with ATAC.

CONCLUSIONS

Higher SMD and higher SMI were significantly associated with lower TAC and its progression in dialysis patients. Improving SMD and SMI could be a new approach for reducing TAC.

POCUS ultrasound: A tool for the detection and monitoring of sarcopenia in peritoneal dialysis

The prevalence of Sarcopenia varies between 1.5% and 68% among patients with chronic kidney disease (CKD). This wide range is due to the different diagnostic tools and the cut-off points used. Early diagnosis and intervention of sarcopenia are essential because of its association with poorer quality of life (QoL), higher hospitalization rates, and adverse events. The "European Working Group on Sarcopenia in Older People (EWGSOP2)" consensus review suggests ultrasound as an emerging tool to quantify muscle mass. Our objective is to describe the prevalence of sarcopenia risk in peritoneal dialysis (PD) and the utility of ultrasound in our setting.

MATERIAL AND METHODS

We conducted an observational study in prevalent PD patients at the Puerta de Hierro University Hospital between January and October 2023. Clinical, efficacy, analytical and nutritional parameters were collected, along with functional performance measured by SPPB, frailty (FRAIL scale), risk of malnutrition (MIS scale), bioimpedance (BCM) and estimation of appendicular skeletal muscle mass using Lin's formula. Ultrasound measurement of supramuscular fat, Axes (X and Y) and the area of the rectus femoris muscle (RFM) were also included, adjusted for height and body surface area. We classified patients at risk of sarcopenia based on handgrip strength according to EWGSOP2 criteria, adjusted for sex. This study was approved by the Ethics Committee of Puerta de Hierro University Hospital (No. 16/2023).

RESULTS

We evaluated 38 patients, with a mean age of 65.4 years (SD 14.9), 65.8% were male. 52.6% had a reduced lean tissue index (LTI) and 23.7% had a reduced fat tissue index (FTI), with a mean phase angle (PA) of 4.5 (SD 1.1). We classified 42.1% as patients at risk of sarcopenia based on handgrip strength. They were older, had more comorbidities, poorer nutrition according to the MIS scale, and showed worse scores on frailty and functional capacity. Similary, they had a lower LTI, lower appendicular skeletal muscle mass, and lower quadriceps muscle thickness (Y axis 8.5 mm (SD 2.4) vs 11.8 mm (SD 3.3) p = 0.002). Patients at risk of sarcopenic had lower phosphorus levels and higher C-reactive protein (CRP) levels. The predictive capacity of ultrasound for classifying patients at risk of sarcopenia was AUC 0.78 (0.64-0.93) for Y Axis, similar to those obtained with the LTI and PA of bioimpedance.

CONCLUSIONS

Sarcopenia risk is highly prevalent in PD and is related to age, comorbidity, malnutrition and inflammation in patients. Ultrasound is an accessible, safe, low-cost and easy-to-use tool at the bedside. This method helps us to quantify muscle mass and assess its quality. We propose the thickness of the RFM (Y axis) as the best complementary parameter given its good correlation with bioimpedance and its diagnostic value for sarcopenic risk. Our experience will serve as a basis for future studies that allow us to define specific cut-off points in PD and design monitoring and intervention protocols.

Association between the coexistence of chronic kidney disease and sarcopenia with cardiovascular disease and mortality

BACKGROUND

Chronic kidney disease (CKD) and sarcopenia are independently associated with adverse cardiovascular and mortality outcomes. However, the combined impact of CKD and sarcopenia remains poorly understood. To evaluate the combined effects of CKD and sarcopenia on cardiovascular disease (CVD) and mortality risks in a large population-based cohort.

METHODS

We analyzed data from 477,380 participants in the UK Biobank, categorized into four groups based on the presence or absence of CKD and sarcopenia: Non-CKD Non-Sarcopenia, Non-CKD Sarcopenia, CKD Non-Sarcopenia, and CKD Sarcopenia. Cox proportional hazards models estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for CVD and mortality outcomes. Kaplan-Meier survival analyses compared event-free survival across the groups.

RESULTS

Participants with both CKD and sarcopenia exhibited the highest risks across all outcomes compared to those without either condition. For stroke, the adjusted HR was 2.17 (95% CI: 1.65-2.86), significantly higher than CKD alone (HR: 1.69, 95% CI: 1.47-1.94) or sarcopenia alone (HR: 1.28, 95% CI: 1.03-1.59). Similar trends were observed for coronary artery disease (CAD) and heart failure (HF), with HRs of 1.53 (95% CI: 1.38-1.69) and 2.22 (95% CI: 1.99-2.47), respectively, in the CKD-sarcopenia group. The coexistence of CKD and sarcopenia was also associated with significantly elevated all-cause mortality (HR: 2.59, 95% CI: 2.17-3.09) and cardiovascular-specific mortality (HR: 4.08, 95% CI: 2.95-5.66).

CONCLUSION

The coexistence of CKD and sarcopenia significantly amplifies the risks of CVD and mortality, highlighting the need for integrated management strategies to address this high-risk population. Early detection and tailored interventions targeting these dual risk factors may mitigate their compounded burden and improve clinical outcomes.

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.

A Comparison Between Severity-Dependent Protocol and Fixed-Dose Regimen of Oral Vitamin D Supplementation on Correction of Hypovitaminosis D Among Dialysis Patients

OBJECTIVE

Low vitamin D status is associated with either low muscle mass or impaired muscle function in dialysis patients. However, there is no consensus on how best to correct hypovitaminosis D, defined as serum 25-hydroxyvitamin D level <30 ng/mL, in patients with end-stage kidney disease (ESKD). This study investigated the effect of different vitamin D supplementation regimens on sarcopenia outcomes in dialysis patients.

METHODS

This was a prospective randomized controlled trial. ESKD patients treated with maintenance hemodialysis (HD) or peritoneal dialysis with low vitamin D status on a ratio of 1:1, were randomized to either receive oral ergocalciferol utilizing a severity-dependent treatment protocol for low vitamin D status suggested by the Kidney Disease Outcomes Quality Initiative as a control group or a fixed-dose regimen of 20,000 international units/week. The changes in muscle mass were measured by bioimpedance spectroscopy, muscle strength was assessed by a hand grip dynamometer, physical performance was determined by gait speed, and muscle-related biomarkers were examined.

RESULTS

A total of 76 dialysis patients were randomized (HD = 43.4%). Baseline characteristics, including age, dialysis vintage, and muscle parameters were similar. After supplementation, the average serum 25-hydroxyvitamin D levels in the severity-dependent and fixed-dose groups were significantly elevated from 14.5 ± 7.3 to 27.2 ± 13.2 ng/mL, P < .001 and from 15.1 ± 6.4 to 28.8 ± 11.5 ng/mL, P < .001, respectively, and did not differ between groups at 6 months (P = .60). Despite comparable energy and protein intake, the mean bioimpedance spectroscopy-derived total body muscle mass normalized to height squared was significantly increased at 6 months in the fixed-dose group (14.5 ± 3.3 to 15.3 ± 3.0 kg/m2, P = .03) compared with the severity-dependent protocol (13.5 ± 2.7 to 13.7 ± 2.9 kg/m2, P = .58). In the subgroup analysis, muscle mass improvement was statistically elevated in peritoneal dialysis patients (P = .01) while unaltered among HD patients (P = .88) in the fixed-dose group. Muscle strength, gait speed, and serum insulin-like growth factor-1 level, as the mediators of muscle cell growth, were not different between the two groups at 6 months (P > .05). Neither hypercalcemia nor hyperphosphatemia was found throughout the study.

CONCLUSION

A fixed-dose ergocalciferol supplementation demonstrates similar performance in the correction of low vitamin D status but better muscle mass improvement than a severity-dependent protocol among ESKD patients. Regular dosing intervals of weekly vitamin D supplementation appear to be a promising treatment for sarcopenia among patients undergoing dialysis.

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.

Recovery time is associated with the onset of cardiovascular disease in Japanese patients undergoing maintenance hemodialysis

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of mortality in patients undergoing maintenance hemodialysis (HD), with various reported risk factors. Recovery time (RT) is a valuable indicator of post-dialysis fatigue. However, the association between RT and the onset of CVD remains unexplored. As such, this study aimed to determine the effect of RT on the onset of CVD.

METHODS

Data from 620 patients undergoing maintenance HD at Yabuki Hospital and 3 related facilities (Yamagata Prefecture, Japan) as of December 31, 2020, were retrospectively analyzed. Patients were asked to respond to the question "How long does it take you to recover from a dialysis session?"; the response was defined as RT. The analysis was performed by categorizing patients into 2 groups according to RT: short RT (< 2 h); and long RT (≥ 2 h). The primary outcome was major adverse cardiovascular events (MACE). Secondary outcomes included all-cause death and hospitalization.

RESULTS

During the 24-month follow-up, 70 (11.3%) patients developed MACE. The long RT group exhibited a higher incidence of MACE; multivariate analysis revealed that age and long RT were associated with the onset of MACE. All-cause death was observed in 45 (7.3%) patients, with no significant difference between the 2 groups. Hospitalization occurred in 252 (40.6%) patients and was more frequent in the long RT group. Multivariate analysis revealed that age, sex, duration of HD, intact parathyroid hormone level, and long RT were associated with hospitalization.

CONCLUSION

Long RT was an independent risk factor for the onset of CVD.

The association between changes in muscle mass and function and mortality in individuals receiving peritoneal dialysis

BACKGROUND/OBJECTIVE

Data in terms of how dynamic changes of muscle mass and function affect mortality in end-stage kidney disease (ESKD) patients undergoing dialysis have led to inconclusive results. The main goal of this research was to determine the association between dynamic deterioration of muscle mass and function and all-cause mortality in ESKD patient on continuous ambulatory peritoneal dialysis (CAPD).

METHODS

Eligible ESKD patients on CAPD were prospectively included, and followed up at 3-month intervals in the tertiary care center for 2 years. Dynamic deterioration of muscle mass and function during a 12-month follow-up period before patients enrolled was the exposure of interest. The deterioration of muscle mass and function was identified utilizing the criteria set by the Asian Working Group on Sarcopenia in 2019 (AWGS 2019). Primary outcome was defined as the all-cause mortality during the next 2-year follow-up period. Kaplan-Meier analysis with log-rank test was used to compare overall survival between groups. Association of dynamic deterioration of muscle mass and function with all-cause mortality was examined by employing Cox proportional hazards models. A sensitivity analysis was also conducted to examine whether the potential association was modified.

RESULTS

A total of 217 eligible patients on CAPD were included. The prevalence of dynamic deterioration of muscle mass and function was 42.9% (93/217), of which that evolving to sarcopenia (nonsevere sarcopenia or severe sarcopenia) from nonsarcopenia was 24.9% (54/217) and that evolving to severe sarcopenia from nonsevere sarcopenia was 18.0% (39/217). A total of 35.0% (76/217) participants died during the 2-year follow-up period, of which the group with deterioration of muscle mass and function was 50.5% (47/93), and the group without deterioration was 23.4% (29/124), with an absolute difference of 27.1% (95%CI 14.5%-39.7%). Kaplan-Meier survival curve revealed that the participants with dynamic deterioration of muscle mass and function had a worse survival rate than those without deterioration (log-rank test, χ2 = 17.46, p < 0.001). After adjustment for potential confounding factors, the dynamic deterioration of muscle mass and function was still significantly associated with increased risk of all-cause mortality (hazard ratio [HR] = 2.40, 95%CI 1.44-4.00, p = 0.001). In sensitivity analysis, the relationship between dynamic deterioration of muscle mass and function (nonsarcopenia to sarcopenia vs without deterioration) and all-cause mortality was consistent (HR = 4.01, 95%CI 2.22-7.22, p < 0.001). Nevertheless, no significant relationship was found in participants who evolved to severe sarcopenia from nonsevere sarcopenia (HR = 1.41, 95%CI 0.72-2.74, p = 0.313).

CONCLUSION

This research demonstrated a significant association between dynamic deterioration of muscle mass and function and higher risk of mortality in ESKD patients on CAPD, and we recommend individualized lifestyle intervention that may be implemented to intervene in the progression of their muscle mass and function across the health care spectrum.

MOTS-c Levels and Sarcopenia Risk in Chronic Peritoneal Dialysis Patients: A Pilot Study

Background and Objectives: Sarcopenia is exceedingly frequent in end-stage kidney disease (ESKD) patients on dialysis, including those undergoing peritoneal dialysis (PD), and is of multifactorial origin. MOTS-c is a mitochondrial-derived peptide that promotes muscle growth whose levels are unbalanced in ESKD. In this study, we evaluated MOTS-c balance and its relationship with sarcopenia risk in an ESKD-PD cohort. Materials and Methods: MOTS-c was measured in serum, urine, and dialysate samples of 32 chronic PD patients. Patients were thus screened for sarcopenia risk by the SARC-F tool, anthropometric measurements, and physical performance tests. Results: PD patients with a very high sarcopenia risk (SARC-F ≥ 2) had significantly lower serum (sMOTS-c) and higher dialysate (dMOTS-c) levels, suggesting an increased peritoneal clearance of this substance (d/s MOTS-c). sMOTS-c levels were directly correlated with muscle performance in physical tests, while an opposite relationship was found with dMOTS-c and d/sMOTS-c. ROC analyses demonstrated the diagnostic potential of MOTS-c, particularly in combination with physical and anthropometric assessments, to identify PD patients at very high risk of sarcopenia. Conclusions: Chronic PD may negatively affect MOTS-c balance, which, in turn, may contribute to enhanced sarcopenia risk. Larger studies are needed to confirm these observations and to validate the potential utility of this substance as a biomarker for improving sarcopenia risk stratification in PD patients.

Effects of Dietary Fiber Supplementation on Modulating Uremic Toxins and Inflammation in Chronic Kidney Disease Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Emerging evidence supports the beneficial effects of dietary fiber supplementation in alleviating gut dysbiosis, which leads to a reduction in uremic toxins and inflammatory markers in chronic kidney disease (CKD) patients. However, current evidence-based renal nutrition guidelines do not provide recommendations regarding dietary fiber intake. We performed a systematic review and meta-analysis to investigate and highlight the effects of dietary fiber supplementation on modulating uremic toxins and inflammatory markers in individuals with CKD, with or without dialysis. The eligible randomized controlled trials (RCTs) were identified from PubMed, Scopus, and Cochrane Central Register of Controlled trials until 27 November 2024. The results were synthesized using a random-effects model and presented as standardized mean differences (SMDs) with a 95% confidence interval (CI). A total of 21 studies with 700 patients were included. When compared with the control group, dietary fiber supplementation ranging from 6 to 50 g/day, for typically more than 4 weeks, could significantly reduce the levels of serum uremic toxins, including p-cresyl sulfate, indoxyl sulfate, and blood urea nitrogen (SMD -0.22, -0.34, -0.25, respectively, with p-values < 0.05), as well as biomarkers of inflammation, including interleukin-6 and tumor necrosis factor alpha (SMD -0.44, -0.34, respectively, with p-values < 0.05). These beneficial effects were consistent across different types of fibers and CKD status (with or without dialysis). However, no significant reduction in serum trimethylamine N-oxide, uric acid, and high-sensitivity C-reactive protein levels was observed with dietary fiber intervention. This study would pave the way for prioritizing dietary quality, particularly a fiber-rich diet, beyond the traditional focus on the quantities of protein, energy, and electrolyte restrictions among individuals with CKD.

Clinical and novel insights into risk factors for sarcopenia in dialysis patients: a systematic review and meta-analysis

OBJECTIVE

We employed a meta-analysis to investigate the risk factors associated with sarcopenia in patients undergoing dialysis.

METHODS

We conducted a search in PubMed, Embase, Cochrane Library, and Web of Science databases. Inclusion criteria included case-control and cohort studies on risk factors for sarcopenia in dialysis patients. The search period spanned from the inception of each database to September 20, 2024. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Data analysis was performed using Stata 15.0.

RESULT

A total of 625 articles were screened, with 610 articles excluded based on predefined eligibility criteria, resulting in 15 articles involving 2904 individuals were included in the final analysis, meta-analysis results indicate that older dialysis patients [SMD = 0.76, 95% CI (0.54, 0.99), I2 = 81%, P = 0.001], those with a lower BMI [SMD = -0.50, 95% CI (-0.80, -0.20), I2% = 87.4%, P = 0.02], a lower SMI [SMD = -2.67, 95% CI (-3.87, -1.47), I2% = 98.2%, P = 0.001], and those with diabetes [OR = 1.43, 95% CI (1.13, 1.82), I2% = 48.8%, P = 0.03] are more likely to develop sarcopenia.

CONCLUSION

Based on current research, our study found that elderly dialysis patients, those with a lower BMI, lower SMI, and diabetic patients are more likely to develop sarcopenia. These findings highlight the necessity of early intervention for these high-risk groups. However, the study has limitations. Future research should address these limitations and investigate the mechanisms linking these risk factors to sarcopenia to develop targeted prevention and treatment strategies.

Association between daily sitting time and sarcopenia in the US population: a cross-sectional study

BACKGROUND

Sarcopenia is an age-related syndrome marked by a gradual decline in skeletal muscle mass and function. While various factors influencing sarcopenia have been studied, the link between daily sedentary time and sarcopenia remains underexplored.

METHOD

This study analyzed the association between daily sitting time and sarcopenia using data from the National Health and Nutrition Examination Survey (NHANES 2011-2018). Daily sitting time was assessed through questionnaires, while sarcopenia was measured using body mass index (BMI) adjusted appendicular skeletal muscle mass (ASM). The relationship was analyzed using weighted logistic regression models and smoothing curves. Stratified analyses and interaction testing were employed to investigate population-specific characteristics of this association. Furthermore, chi-square test and grouped logistic regression were used to further analyze the impact of vigorous activity on the relationship between the two variables.

RESULT

This study included 9998 participants with complete information. The fully adjusted model showed a significant positive correlation between daily sitting time and the prevalence of sarcopenia (OR = 1.07, 95% CI: 1.03-1.10, P = 0.0026). The group with daily sitting time ≥ 9 h had a 90% higher risk of sarcopenia compared to the < 4 h group (OR = 1.90, 95% CI: 1.22-2.84, P = 0.0040). Smooth curve fitting analysis showed a linear correlation between this relationship. Stratified analysis shows that non-Hispanic white men with a lower BMI (BMI < 25) have a higher risk of sarcopenia. Compared to those who actively participate in vigorous activities, individuals who lack recreational activities have a higher prevalence and risk of sarcopenia.

CONCLUSION

Our research has found that increased sedentary time significantly increases the risk of sarcopenia, especially among non-Hispanic white men with lower BMI. Additionally, individuals who lack vigorous physical activity also have a higher prevalence and risk of sarcopenia. Therefore, reducing sedentary behavior and increasing moderate exercise may be effective prevention strategies.

Risk Prediction Models for Sarcopenia in Dialysis Patients: A Systematic Review

Nowadays, numerous studies have developed risk prediction models for sarcopenia in dialysis patients. However, the quality and performance of these models have not been integrated. The purpose of our study is to provide a comprehensive overview of the current risk prediction models for sarcopenia in dialysis patients and to offer a reference for the development of high-quality prediction models. Ten electronic databases were searched from inception to March 8, 2024. Two researchers independently assessed the risk of bias and applicability of the studies, and used Revman, 5.4, software to conduct a meta-analysis of common predictors in the models. A total of 12 studies described 13 risk prediction models for dialysis patients with sarcopenia. In dialysis patients, the prevalence of sarcopenia ranged from 6.60% to 63.73%. The area under curve (AUC) of the 13 models ranged from 0.776 to 0.945. Only six models (AUC ranging from 0.73 to 0.832) were internally validated, while two were externally evaluated (AUC ranging from 0.913 to 0.955). Most studies had a high risk of bias. The most common effective predictors in the models were age, body mass index, muscle circumference, and C-reactive protein. Our study suggests that developing a prediction model for the onset of sarcopenia in dialysis patients requires a rigorous design scheme, and future verification methods will necessitate multicenter external validation.

Handgrip strength and body mass index exhibit good predictive value for sarcopenia in patients on peritoneal dialysis

Aim

The diagnosis of sarcopenia in patients on peritoneal dialysis (PD) in clinics is limited owing to its relatively complicated process and the need for expensive assessment equipment. This study aimed to develop and validate sex-specific nomogram models based on body mass index (BMI), handgrip strength, and other routine follow-up examination indicators to predict sarcopenia in patients on PD.

Methods

From March 2023 to February 2024, 699 eligible patients were recruited from the PD centers of two tertiary hospitals in southeastern China. Routine follow-up examination indicators such as age, BMI, biochemical indicators, dialysis adequacy, handgrip strength, and five-repetition sit-to-stand test, were used as potential predictive variables. Multivariate logistic regression analyses were used to separately determine the predictive factors for men and women. Nomogram models were constructed based on the results of the multivariate analyses, which were internally validated using a bootstrap re-sampling method (n = 2000). Predictive performance was validated using a receiver operating characteristic (ROC) curve.

Results

The prevalence of sarcopenia in Chinese patients on PD was 13.92%. The nomogram models based on multivariate analyses revealed both handgrip strength and BMI as independent predictors of sarcopenia in men and women on PD. The bootstrap-corrected area under the ROC curves of the models was 0.924 (95% CI: 0.888-0.959) and 0.936 (95% CI, 0.906-0.966) for men and women, respectively. The calibration curves of both models demonstrated high consistency between the observed and anticipated values.

Conclusion

The two nomogram models based on BMI and handgrip strength demonstrated good predictive ability for sarcopenia in male and female patients on PD. Subsequently, these may be used as convenient and inexpensive methods for the early detection and timely management of sarcopenia in patients on PD.

Male Sex and Ageing are Independent Risk Factors for Sarcopenia Stage in Patients With Chronic Kidney Disease Not Yet on Dialysis

BACKGROUND

The risk of sarcopenia in older adults with chronic kidney disease (CKD) not yet on dialysis is controversial. The aims of this study were to investigate the association among sarcopenia, diabetes and predialysis CKD and evaluate the impact of gender and ageing on the risk of sarcopenia statuses in older patients with predialysis CKD.

METHODS

The participants aged ≥60 years old were recruited from the community of New Taipei City, Taiwan. Handgrip strength, appendicular skeletal muscle mass and the 6-m walk were measured. The diagnosis of sarcopenia was established based on the consensus of Asian Sarcopenia Working Group 2019. These older adults were categorised into G1, G2 and G3-5 according to the guidelines of Kidney Disease Improving Global Outcomes (KDIGO) after calculating the estimated glomerular filtration rate by the Modification of Diet in Renal Disease equation. The Chi-square test and ANOVA were used to estimate the difference of categorical and continuous variables, respectively. Polytomous logistic regression was employed to assess the odds ratio (OR) and 95% confidence intervals (CIs) of the sarcopenia status and sarcopenia-associated risk factors in the predialysis CKD patients. All tests were two-sided, and p < 0.05 was defined as statistical significance.

RESULTS

Among the 3648 older adults (mean age: 71.9 ± 6.07 years), including 1701 males and 1947 females, 870 (23.9%), 94 (2.58%) and 48 (1.32%) had possible sarcopenia, sarcopenia and severe sarcopenia, respectively. After adjustment, the risk for possible sarcopenia, sarcopenia and severe sarcopenia significantly increased with ageing (OR = 1.11, 1.10 and 1.23; 95% CI = 1.10-1.13, 1.07-1.15 and 1.18-1.30, respectively) and male gender (OR = 2.26, 20.3 and 25.4; 95% CI = 1.87-2.73, 11.5-36.0 and 11.3-57.2, respectively). Compared with KDIGO G1, no significant association between KDIGO G3-5 and the statuses of sarcopenia was observed (OR = 0.97, 0.88 and 0.91; 95% CI = 0.75-1.26, 0.43-1.78 and 0.37-2.27, p = 0.821, 0.718, 0.838, for possible sarcopenia, sarcopenia and severe sarcopenia, respectively). Ageing and male gender indicated a significant risk for higher sarcopenia status in older patients with predialysis CKD (0.027-fold/year and 0.284-fold, respectively) (p < 0.0001).

CONCLUSIONS

This study illuminated the importance of the male sex and the ageing process on the risk of sarcopenia progression in patients with predialysis CKD. Early clinical screening and aggressive treatment for the prevention of higher sarcopenia status in advanced older male adults with predialysis CKD are recommended.

Association of sarcopenia and its prognostic value in symptomatic knee osteoarthritis among older people in China: the first longitudinal evidence from CHARLS

BACKGROUND

Sarcopenia and knee osteoarthritis (KOA) are two common musculoskeletal disorders, often coexisting in aged population and potentially influencing each other. However, the underlying relationship between two conditions remains unclear and controversial. To fill this knowledge gap, we aimed to investigate the longitudinal association among the older Chinese population.

METHODS

Data were attracted from 2 waves of the China Health and Retirement Longitudinal Study (CHARLS), and 6212 individuals aged ≥ 60 years were included. Sarcopenia status was defined by the Asian Working Group for Sarcopenia 2019 criteria. Multivariate logistic regression and generalized estimation equation models were applied to estimate the impact of sarcopenia on KOA. A prognostic nomogram was developed through train-test cross-validation.

RESULTS

At baseline in CHARLS 2015, the prevalence of symptomatic KOA was 12.7% (792/6212) in total population, 9% (270/2996) in no-sarcopenia group, 17.5% (286/1638) in possible sarcopenia group, and 15.0% (236/1578) in sarcopenia group. Over a 3-year follow-up, 4980 respondents were included, with incident KOA cases identified as 56 (2.2%), 38 (3.0%), and 43 (3.6%) in no-sarcopenia, possible sarcopenia, and sarcopenia groups, respectively. Sarcopenia was significantly associated with increased new-onset KOA compared to no-sarcopenia peers in the fully adjusted model (OR: 1.91, 95% CI: 1.15-3.18), whereas this association was non-significant for possible sarcopenia. In females, low muscle mass alone significantly increased the incident risk of KOA (OR: 2.58, 95% CI: 1.05-6.49). The final prognostic model and nomogram, including sarcopenia status, age, gender, body mass index, self-reported health status, comorbidities, history of falls and physical activity, had a considerable discrimination (AUC = 0.744, C-index = 0.660). The calibration curve indicated significant agreement between predicted and actual observations. Decision curve analysis revealed net benefits for clinical intervention at a probability threshold of 1-17%.

CONCLUSIONS

Sarcopenia was associated with a higher incident risk of symptomatic KOA, wherein low muscle mass may play an important role. The inferior prognosis of sarcopenia in KOA needs more attention in clinical practice.

The gut microbiome, chronic kidney disease, and sarcopenia

Sarcopenia is a prevalent condition in patients with chronic kidney disease (CKD), intricately linked to adverse prognoses, heightened cardiovascular risks, and increased mortality rates. Extensive studies have found a close and complex association between gut microbiota, kidney and muscle. On one front, patients with CKD manifest disturbances in gut microbiota and alterations in serum metabolites. These abnormal microbiota composition and metabolites in turn participate in the development of CKD. On another front, altered gut microbiota and its metabolites may lead to significant changes in metabolic homeostasis and inflammation, ultimately contributing to the onset of sarcopenia. The disturbance of gut microbial homeostasis, coupled with the accumulation of toxic metabolites, exerts deleterious effects on skeletal muscles in CKD patients with sarcopenia. This review meticulously describes the alterations observed in gut microbiota and its serum metabolites in CKD and sarcopenia patients, providing a comprehensive overview of pertinent studies. By delving into the intricate interplay of gut microbiota and serum metabolites in CKD-associated sarcopenia, we aim to unveil novel treatment strategies for ameliorating their symptoms and prognosis.

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.

Individual and joint association of Life's Essential 8 metrics with pre-sarcopenia among U.S. adults

BACKGROUND

In recent times, the American Heart Association has updated its approach to evaluating cardiovascular health (CVH) by replacing the previous "Life's Simple 7" with the more demanding "Life's Essential 8" (LE8). However, the impact of enhancing CVH on reducing the risk of pre-sarcopenia and the association of LE8 metrics with pre-sarcopenia remain unexplored.

METHODS

LE8 score was calculated among 9857 participants. Multivariable logistic regression was utilized to investigate the associations between LE8 and pre-sarcopenia. Additionally, the weighted quantile sum (WQS) model was employed to determine the combined and individual impact of LE8 metrics on pre-sarcopenia. To assess the indirect effects of peripheral immune responses on the relationships between cardiovascular health and pre-sarcopenia, mediation analyses were performed.

RESULTS

In this study, 827 participants had pre-sarcopenia. After accounting for potential confounding factors, the group with excellent cardiovascular health demonstrated an 83% lower risk of pre-sarcopenia compared to the poor cardiovascular health group (OR: 0.17, 95% CI: 0.11-0.27) and a 33% decreased risk of pre-sarcopenia for each 10-point increase in LE8 score (OR: 0.67, 95% CI: 0.62-0.73). Body mass index (BMI) and physical activity (PA) were the critical contributors that decreased the prevalence of pre-sarcopenia in the obese and non-obese populations, respectively.

CONCLUSIONS

A negative association was found between LE8 score and pre-sarcopenia prevalence. Body mass index and physical activity are the primary contributors to the obese and non-obese populations, respectively.

Lower risk of the deterioration of muscle mass and function in oral active vitamin D users among Incident peritoneal dialysis patients: a 12-month follow-up cohort study

Data in terms of how active vitamin D supplementation affects muscle mass and function in end-stage renal disease (ESRD) patients has led to inconclusive results. The main goal of this research was to examine the association of active vitamin D supplementation and risk of the deterioration of muscle mass and function among ESRD patients on peritoneal dialysis (PD). Eligible ESRD patients on PD were prospectively included, and followed up at 3-month intervals in the tertiary care center. Based on the medications during the 12-month follow-up period, the patients were divided into two groups (vitamin D users and non-users). The deterioration of muscle mass and function was identified utilizing the criteria set by the Asian Working Group on Sarcopenia in 2019 (AWGS 2019). Primary outcome was defined as the deterioration of muscle mass and function at the end of the 12-month follow-up. The absolute diffecence and 95% confidence interval (CI) of the incidence of deterioration between vitamin D users and non-users was estimated. The association of vitamin D supplementation with risk of the deterioration of muscle mass and function during the 12-month follow-up period, was examined by employing multivariate logistic regression models. A total of 229 incident PD patients (6 of whom were lost in follow-up) were included. During the entire study period, 54.7% (122/223) of the remaining patients were considered users of oral active vitamin D. The incidence of deterioration in muscle mass and function was 30.5% (68/223) throughout the entire follow-up. In this regard, the rate was 23.0% (28/122) that received oral active vitamin D, while it was 39.6% (40/101) in the group that did not receive it, with an absolute diffecence of -16.6% (95% CI - 4.5, - 28.7) and an estimated relative risk (RR) of 0.784 (95% CI 0.651-0.943). After adjustment for potential confounding factors in logistic regression model, vitamin D users group was still associated with decreased risk of the deterioration of muscle mass and function (OR 0.330, 95% CI 0.159-0.683, P = 0.003). In secondary analysis, the relationship between oral active vitamin D and the deterioration of muscle mass and function remained consistent (≤ 0.25 µg per day vs. non-users; OR 0.300, 95% CI 0.131-0.688, P = 0.004); however, no significant relationship was identified in patients receiving a mean daily dose of > 0.25 µg compared with non-users (OR 0.389, 95% CI 0.146-1.034, P = 0.058). These results indicate that active vitamin D supplementation was significantly associated with a decreased risk of the deterioration of muscle mass and function in incident PD patients with ESRD. However, the amount and type of vitamin D used and the duration of the intervention warrant further randomized controlled trials to confirm the possibility that such medication improves sarcopenia in ESRD patients.

Replacement of the massive amino acid losses induced by hemodialysis: A new treatment option proposal for a largely underestimated issue

BACKGROUND

A series of interesting literature reports acknowledges the notable loss of essential and non-essential amino acids (EAAs and NEAAs) during hemodialysis sessions. These losses may exceed 800 g/year, thus contributing towards accelerating the onset of malnutrition in hemodialysis patients (HD).

OBJECTIVE

A novel tailored amino acid formula for oral administration was developed to replace total amounts of each individual amino acid lost during dialysis diffusive/convective HD strategies, monitoring the effects produced on nutritional and hematological status.

METHODS

A three-month randomized double-blind study was conducted on 30 subjects over the age of 70 years extrapolated from a total population of 86 hemodialysis patients. The 30 patients were randomly assigned to two groups: a treatment group of 15 HD patients (TG) to whom a novel mixture containing 5.4 g of AAs was administered solely on interdialytic days, and a control group of 15 HD patients (CG) who received no amino acid supplementation. The AAs mixture was administered post-dialysis at an extended interval from the end of solute and compartmental rebound to replace AA losses and optimize their role in protein anabolism.

RESULTS

The results obtained highlighted a significant improvement in protein intake g/kg/day (Protein Catabolic Rate, p = 0.014), and increased IgG (p = 0.008) and C3 serum levels (p = 0.003) in the TG group alone. Fat mass losses were initially confirmed by means of bioelectrical impedance analysis (BIA) (p = 0.011) and plicometry (p < 0.001) in the CG group alone, although the main objective was to preserve nutritional status and, particularly, muscle mass. The study was extended to investigate the effects produced on anemia, yielding evidence of continued positive effects three months after the end of the study in the TG group alone based on an increase in Hb levels from 11.2 ± 0.6 to 12.1 ± 0.6 (p = 0.004) associated with a reduced demand for erythropoietin i.v. from 12928 ± 9033 to 9286 ± 5398 U.I/week (p = 0.012) and iron i.v. from 75.9 ± 55 to 71.4 ± 33.4 mg/week (p = 0.045).

CONCLUSIONS

The results obtained following oral administration of this novel tailored AA replacement mixture aimed at reinstating the high AA losses produced during hemodialysis suggest the mixture should be prescribed as a standard procedure to all HD patients.

Muscle quality and major adverse cardiovascular events in post-acute myocardial infarction: A prospective cohort study

BACKGROUND & AIMS

Functional muscle quality, as assessed through the muscle quality index (MQI), represents a contemporary method to measure the capacity to generate force. Despite its potential, the prognostic significance of MQI remains uncertain in various clinical conditions, particularly among patients following acute myocardial infarction (AMI). In light of this, our study sought to evaluate the prognostic relevance of MQI concerning major adverse cardiovascular events (MACE) in patients following AMI.

METHODS AND RESULTS

This is a secondary analysis of a prospective cohort study that included subjects aged ≥20 years from a Cardiovascular Unit Hospital. Functional muscle quality was estimated using MQI, defined as the ratio of handgrip strength (HGS) to muscle mass (MM) derived from bioelectrical impedance analysis. The outcomes included prolonged length of hospital stay, new adverse cardiovascular events (AMI, stroke and hospital readmission for unstable angina), and cardiovascular mortality. A composite score comprising all adverse events over the 1-year follow-up was calculated and defined as MACE. This study included 163 patients, with a median age of 61 years (IQ: 54-69 years), and the majority consisted of males (76.1%). Individual components of the functional muscle quality (HGS and MM) were not associated with any of the adverse outcomes. Only MQI was associated mortality over the 1-year follow-up. For each increase in MQI, the hazard of mortality decreases: adjusted HR: 0.08 (95% CI 0.01-0.84).

CONCLUSION

Functional muscle quality assessed by the MQI may be a valuable clinical predictor of 1-year cardiovascular mortality in patients hospitalized post-AMI.

Comparative analysis of Sarcopenia in hospitalized elderly: exploring the impact of liver cirrhosis

The progressive aging of the population has led to a rise in geriatric pathologies, with sarcopenia, characterized by muscle mass and function loss, becoming a crucial prognostic indicator. This study investigates sarcopenia in elderly hospitalized patients with advanced chronic liver disease (cirrhotic) and non-liver disease patients, comparing their prevalence and exploring correlations with anthropometric and biochemical factors. The cohort of 115 patients, including 50 cirrhotic and 65 non-cirrhotic individuals, exhibited significant comorbidities and a mean age of 78.4 years. Cirrhotic patients presented distinct laboratory parameters indicating liver damage. Applying European Working Group on Sarcopenia in Older People criteria, probable sarcopenia prevalence was similar in cirrhotic (62%) and non-cirrhotic (63%) patients. Stratifying probable sarcopenia into confirmed sarcopenia and dynapenia revealed no significant differences between populations. Correlation analyses demonstrated positive associations between Appendicular Skeletal Muscle Mass (ASM) and anthropometric parameters, malnutrition risk, and grip strength. In cirrhotic patients, muscle mass inversely correlated with liver damage. Odds ratio analysis highlighted the Mini Nutritional Assesment's (MNA) significant predictive capability for sarcopenia. ROC curve analysis affirmed MNA and biochemical markers' combined use, such as transferrin, albumin, total cholesterol, lymphocyte count and C-reactive protein as a strong predictor. Despite limitations, such as a small sample size, this study underscores the significance of thorough sarcopenia screening in elderly hospitalized patients, especially those with cirrhosis. Indeed, individuals with end-stage liver disease are particularly susceptible to sarcopenia. A more personalized approach utilizing tools like MNA and biochemical markers could prove beneficial. Further research is warranted to validate these findings and inform clinical interventions.

Sarcopenia is associated with increased major adverse cardiovascular event incidence in maintenance hemodialysis patients: a prospective cohort study and mediation analysis

Background

Few studies have investigated the relationship between sarcopenia and the incidence of major adverse cardiovascular events (MACE), which are common complications in maintenance hemodialysis (MHD) patients. This study thus explored the association between sarcopenia and MACE in a prospective cohort with mediation analysis.

Methods

Adult MHD patients in Jiangdu People's Hospital in December 2019 were screened. The exposure was sarcopenia, as defined by the 2019 Asian Working Group. The primary endpoint was the occurrence of MACE, defined as the composite of all-cause mortality or hospital admission with a primary diagnosis of acute myocardial infarction, stroke, or heart failure during a 3-year follow-up period. Multivariate Cox regression analyses were used to test the association between sarcopenia and subsequent MACE incidence. Mediation analyses were used to investigate whether potential mediators influenced the association between sarcopenia and MACE.

Results

Of the 230 patients enrolled, 57% were male, with a median age of 57 years (interquartile range [IQR]: 50 to 66), and a median dialysis vintage of 67 months (IQR: 32 to 119). The prevalence of sarcopenia was 45.2%. The presence of sarcopenia was significantly correlated with age (Spearman's r = 0.47, p < 0.001), C-reactive protein (Spearman's r = 0.13, p = 0.044), serum albumin (Spearman's r = -0.22, p < 0.001), 25(OH) vitamin D (Spearman's r = -0.26, p < 0.001), and coronary artery calcification score (Spearman's r = 0.20, p = 0.002). Over the 3-year follow-up period, MACE were observed in 59/104 (56.7%) patients with sarcopenia and 38/126 (30.2%) patients without sarcopenia (log-rank p < 0.001). After accounting for potential confounders, patients with sarcopenia presented a 66% (4-168%, p = 0.035) increase in their risk of MACE incidence as compared to non-sarcopenic individuals. However, adjusted mediation analyses did not detect any indication of a causal mediation pathway linking the effects of sarcopenic status on coronary artery calcification score, C-reactive protein, serum albumin, or 25(OH) vitamin D levels to MACE outcomes. Conversely, sarcopenia exhibited a potential direct effect (average direct effect range: -1.52 to -1.37, all p < 0.05) on MACE incidence.

Conclusion

These results revealed that the presence of sarcopenia was associated with a higher incidence of MACE in MHD patients. The putative effects of sarcopenia on this cardiovascular endpoint are possibly not mediated by any causal pathways that include vascular calcification, inflammation, hypoalbuminemia, or vitamin D.

Identification of nicotinamide N-methyltransferase as a promising therapeutic target for sarcopenia

Sarcopenia is a significant geriatric syndrome that involves the loss of skeletal muscle mass and strength. Due to its substantial endocrine role, the metabolic microenvironment of skeletal muscle undergoes changes with age. Examining the pathogenesis of sarcopenia through focusing on metabolic dysregulation could offer insights for developing more effective intervention strategies. In this study, we analyzed the transcriptomics data to identify specific genes involved in the regulation of metabolism in skeletal muscle during the development of sarcopenia. Three machine learning algorithms were employed to screen key target genes exhibiting strong correlations with metabolism, which were further validated using RNA-sequencing data and publicly accessible datasets. Among them, the metabolic enzyme nicotinamide N-methyltransferase (NNMT) was elevated in sarcopenia, and predicted sarcopenia with an area under the curve exceeding 0.7, suggesting it as a potential therapeutic target for sarcopenia. As expected, inhibition of NNMT improved the grip strength in aging mice and alleviated age-related decline in the mass index of the quadriceps femoris muscles and whole-body lean mass index. Additionally, the NNMTi treatment increased the levels of nicotinamide adenine dinucleotide (NAD+) content, as well as PGC1α and p-AMPK expression in the muscles of both the D-galactose-treated mouse model and naturally aging mouse model. Overall, this work demonstrates NNMT as a promising target for preventing age-related decline in muscle mass and strength.

Machine learning for identification of short-term all-cause and cardiovascular deaths among patients undergoing peritoneal dialysis

Although more and more cardiovascular risk factors have been verified in peritoneal dialysis (PD) populations in different countries and regions, it is still difficult for clinicians to accurately and individually predict death in the near future. We aimed to develop and validate machine learning-based models to predict near-term all-cause and cardiovascular death. Machine learning models were developed among 7539 PD patients, which were randomly divided into a training set and an internal test set by five random shuffles of 5-fold cross-validation, to predict the cardiovascular death and all-cause death in 3 months. We chose objectively collected markers such as patient demographics, clinical characteristics, laboratory data, and dialysis-related variables to inform the models and assessed the predictive performance using a range of common performance metrics, such as sensitivity, positive predictive values, the area under the receiver operating curve (AUROC), and the area under the precision recall curve. In the test set, the CVDformer models had a AUROC of 0.8767 (0.8129, 0.9045) and 0.9026 (0.8404, 0.9352) and area under the precision recall curve of 0.9338 (0.8134,0.9453) and 0.9073 (0.8412, 0.9164) in predicting near-term all-cause death and cardiovascular death, respectively. The CVDformer models had high sensitivity and positive predictive values for predicting all-cause and cardiovascular deaths in 3 months in our PD population. Further calibration is warranted in the future.

The Mitochondrial-Derived Peptide MOTS-c May Refine Mortality and Cardiovascular Risk Prediction in Chronic Hemodialysis Patients: A Multicenter Cohort Study

INTRODUCTION

Uremic patients exhibit remarkably increased rates of mortality and cardiovascular (CV) events, but risk prediction in this setting remains difficult. Systemic mitochondrial dysfunction is pervasive in end-stage kidney disease and may contribute to CV complications. We tested the clinical significance of circulating MOTS-c, a small mitochondrial-derived peptide, as a biomarker for improving mortality and CV risk prediction in hemodialysis (HD) patients.

METHODS

We conducted a prospective, observational, multicenter study on 94 prevalent HD patients. The study endpoint was a composite of all-cause mortality and non-fatal CV events. The diagnostic and prognostic capacities of predictive models based on cohort-related risk factors were tested before and after the inclusion of MOTS-c.

RESULTS

MOTS-c levels were higher in HD patients than in controls (p < 0.001) and even more elevated (p = 0.01) in the 53 individuals experiencing the combined endpoint during follow-up (median duration: 26.5 months). MOTS-c was independently associated with the endpoint at either multivariate logistic (OR 1.020; 95% CI: 1.011-1.109; p = 0.03) or Cox regression analyses (HR 1.004; 95% CI: 1.000-1.025; p = 0.05) and the addition of this biomarker to prognostic models including the other cohort-related risk predictors (age, left ventricular mass, evidence of diastolic dysfunction, diabetes, pulse pressure) significantly improved the calibration, risk variability explanation, discrimination (receiver operating characteristic area under the curve from 0.727 to 0.743; C-index from 0.658 to 0.700), and particularly, the overall reclassification capacity (NRI 15.87%; p = 0.01).

CONCLUSIONS

In HD patients, the mitochondrial-derived peptide MOTS-c may impart significant information to refine CV risk prediction, beyond cohort-related risk factors. Future investigations are needed to generalize these findings in larger and more heterogeneous cohorts.

Adipokines and Myokines as Markers of Malnutrition and Sarcopenia in Patients Receiving Kidney Replacement Therapy: An Observational, Cross-Sectional Study

Chronic kidney disease (CKD) is linked to an elevated risk of malnutrition and sarcopenia, contributing to the intricate network of CKD-related metabolic disorders. Adipokines and myokines are markers and effectors of sarcopenia and nutritional status. The aim of this study was to assess whether the adipokine-myokine signature in patients on kidney replacement therapy could help identify malnutrition and sarcopenia. The study involved three groups: 84 hemodialysis (HD) patients, 44 peritoneal dialysis (PD) patients, and 52 kidney transplant recipients (KTR). Mean age was 56.1 ± 16.3 years. Malnutrition was defined using the 7-Point Subjective Global Assessment (SGA) and the Malnutrition-Inflammation Score (MIS). Sarcopenia was diagnosed based on reduced handgrip strength (HGS) and diminished muscle mass. Concentrations of adipokines and myokines were determined using the enzyme-linked immunosorbent assay (ELISA). 32.8% of all study participants were identified as malnourished and 20.6% had sarcopenia. For malnutrition, assessed using the 7-Point SGA, in ROC analysis albumin (area under the curve (AUC) 0.67 was the best single biomarker identified. In dialysis patients, myostatin (AUC 0.79) and IL-6 (AUC 0.67) had a high discrimination value for sarcopenia, and we were able to develop a prediction model for sarcopenia, including age, albumin, adiponectin, and myostatin levels, with an AUC of 0.806 (95% CI: 0.721-0.891). Adipokines and myokines appear to be useful laboratory markers for assessing malnutrition and sarcopenia. The formula we propose could contribute to a better understanding of sarcopenia and potentially lead to more effective interventions and management strategies for dialysis patients.

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.

Biomarkers of chronic kidney disease in older individuals: navigating complexity in diagnosis

Chronic kidney disease (CKD) in older individuals is a matter of growing concern in the field of public health across the globe. Indeed, prevalence of kidney function impairment increases with advancing age and is often exacerbated by age-induced modifications of kidney function, presence of chronic diseases such as diabetes, hypertension, and cardiovascular disorders, and increased burden related to frailty, cognitive impairment and sarcopenia. Accurate assessment of CKD in older individuals is crucial for timely intervention and management and relies heavily on biomarkers for disease diagnosis and monitoring. However, the interpretation of these biomarkers in older patients may be complex due to interplays between CKD, aging, chronic diseases and geriatric syndromes. Biomarkers such as serum creatinine, estimated glomerular filtration rate (eGFR), and albuminuria can be significantly altered by systemic inflammation, metabolic changes, and medication use commonly seen in this population. To overcome the limitations of traditional biomarkers, several innovative proteins have been investigated as potential, in this review we aimed at consolidating the existing data concerning the geriatric aspects of CKD, describing the challenges and considerations in using traditional and innovative biomarkers to assess CKD in older patients, highlighting the need for integration of the clinical context to improve biomarkers' accuracy.

The non-linear associations between blood manganese level and sarcopenia in patients undergoing maintenance hemodialysis: A multicenter cross-sectional study

BACKGROUND AND AIMS

Manganese (Mn), a vital element in energy metabolism, is predominantly stored in skeletal muscles and plays a crucial role in muscle function and strength. Patients on maintenance hemodialysis (MHD) often experience muscle wasting due to metabolic disruption and inflammation. This study aimed to explore the relationship between blood Mn levels and sarcopenia in a patient population.

METHODS

In this multicenter cross-sectional study, conducted from March 2021 to March 2022, 386 patients on MHD from three medical centers were included. Blood Mn levels were measured using inductively coupled plasma mass spectrometry, and body composition was assessed post-dialysis using bioelectrical impedance analysis. Grip strength was measured using a digital dynamometer. The patients were categorized into groups with and without sarcopenia. Using a generalized additive model to fit a smooth curve, we employed a generalized linear model to identify the optimal inflection point and explore the threshold effect after discovering a segmented relationship. Subsequently, a binary logistic regression analysis was conducted to investigate the relationship between blood manganese levels and the risk of sarcopenia, with adjustments made for potential confounding factors.

RESULTS

A negative correlation was observed between blood Mn levels and sarcopenia-related parameters (Appendicular Skeletal Muscle Mass Index and grip strength) in Spearman's correlation analysis (both P < 0.05). After adjusting for confounding factors, a nonlinear association was identified. When blood Mn was ≤ 10.6 μg/L, the increase in sarcopenia was not statistically significant (P > 0.05). Conversely, when blood Mn exceeded 10.6 μg/L, each 1 μg/L increase raised the risk of sarcopenia by 0.1 times. Considering confounders, multivariate binary logistic regression confirmed an independent association between elevated blood Mn levels and sarcopenia.

CONCLUSION

This study revealed an independent association between elevated blood Mn levels (> 10.6 μg/L) and sarcopenia in patients undergoing MHD. These findings emphasize the importance of understanding the Mn metabolism in the context of muscle health in this patient population. Further research is warranted to explore the underlying mechanisms and potential interventions for mitigating sarcopenia in patients with elevated blood Mn levels undergoing MHD.

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.

Association between sarcopenia and sleep disorders: a cross-sectional population based study

Objective

Sleep disorders is a worldwide public health problem. We sought to examine the association between sarcopenia, a decline in skeletal muscle mass and function, and sleep disorders within the adult demographic of the United States during the period spanning 2011 to 2018.

Methods

Diagnosis of sarcopenia and sleep disorders was ascertained through appropriate calculations and a structured questionnaire. The primary correlation analysis was conducted using a weighted multivariate logistic regression model. Furthermore, to confirm the presence of a potential non-linear association between sarcopenia and sleep disorders, additional analyses were performed using multivariate logistic regression and restricted cubic spline (RCS) regression with dose-response curve analysis. Subgroup analyses were also conducted to explore the influence of relevant socio-demographic factors and other covariates.

Results

The final analysis encompassed 5,616 participants. Model 4, inclusive of all pertinent covariates, revealed a positive correlation between sarcopenia and sleep disorders, yielding an odds ratio (OR) of 1.732 (95% CI: 1.182-2.547; P = 0.002). Further analysis, utilizing the restricted cubic spline model, indicated a decreasing trend in sleep disorders as sarcopenia indices rose. Stratified analyses across diverse variables underscored the significant impact of sarcopenia on sleep disorders prevalence in several subgroups. Specifically, males, individuals aged 40 and above, non-Hispanic whites, those with high school education or equivalent, unmarried individuals, obese individuals (BMI ≥ 30), alcohol drinkers, former smokers, diabetics, and those engaging in less rigorous recreational activities exhibited a more pronounced association between sarcopenia and sleep disorders. The incidence of sleep disorders exhibited an upward trend as the incidence of sarcopenia declined among study participants.

Conclusions

In summary, our study provides evidence of an association between sarcopenia and the prevalence of sleep disorders, with a negative correlation observed between the sarcopenia index and the odds ratio of sleep disorders. These findings suggest that maintaining optimal muscle mass may have a beneficial impact on sleep-related issues. In terms of exploring the mechanisms underlying the relationship between sarcopenia and sleep disorders, more in-depth research is warranted to ascertain the definitive causal relationship.

Early Detection of Inflammation and Malnutrition and Prediction of Acute Events in Hemodialysis Patients through PINI (Prognostic Inflammatory and Nutritional Index)

Protein-energy wasting and inflammation are major risk factors for complications in hemodialysis patients. As these risk factors are triggered by a pro-inflammatory state, oxidative stress and hemodynamic dysfunction, which overlap in hemodialyzed subjects, we aimed to assess the efficacy of a cost-effective and straightforward screening tool, the Prognostic Inflammatory and Nutritional Index (PINI), in regularly screening maintenance hemodialysis (MHD) patients, to detect early signs of inflammation and malnutrition. A 12-month follow-up was carried out on a cohort of 102 adult patients undergoing maintenance dialysis, during which the Prognostic Inflammatory and Nutritional Index (PINI) was calculated using the formula alpha1-Acid Glycoprotein (AGP) × C-reactive protein (CRP)/albumin (ALB) × transthyretin (TTR). A PINI score < 1 was considered normal. The patients were stratified based on their PINI score: 66 patients (64.70%) had a normal score, below 1, while 36 patients (35.30%) had a PINI score ≥ 1. Despite the absence of clinical evidence of inflammation at enrollment, the latter group exhibited higher levels of CRP. During the follow-up period, all patients with a PINI score ≥ 1 experienced at least one acute event, compared to only 6% of patients with a normal PINI score, which presented COVID-19 infection as an acute event. The evaluation of the PINI can effectively identify the silent malnutrition-inflammation syndrome and predict the risk of acute events. This straightforward test appears to be a rapid tool that is independent of the examiner's experience and subjectivity, thereby potentially reducing hospitalization costs.

Associations between pinch strength, cardiovascular events and all-cause mortality in patients undergoing maintenance hemodialysis

BACKGROUND AND AIMS

Patients undergoing maintenance hemodialysis (MHD) experience increased mortality and cardiovascular disease (CVD) risks; however, the potential connection between pinch strength (PS) and the prognosis of these patients remains unknown. Consequently, this study aimed to comprehensively assess the influence of PS and handgrip strength (HGS) on both survival and cardiovascular events (CVE) in patients undergoing MHD.

METHODS

Data were gathered from patients undergoing MHD at the Hemodialysis Center of Guangzhou Red Cross Hospital in March 2021. We performed a retrospective follow-up spanning 24 months, with death serving as the primary endpoint for observation and CVE as the secondary endpoint. Multifactorial Cox regression analysis, Kaplan-Meier survival curves, trend tests, and restricted cubic spline were applied to explore the association.

RESULTS

During a 24-month follow-up, data were collected from 140 patients undergoing MHD with an average age of 66.71 ± 12.61 years. Among them, 52 (37.14%) experienced mortality, whereas 36 (40.00%) had CVE without baseline CVD. Kaplan-Meier survival curves demonstrated better survival rates and reduced CVE risk for patients in the second, third, and fourth quartiles compared with those in the first quartile for PS. Adjusted analyses in different models revealed higher PS levels were independently associated with all-cause mortality (major model, model 4, HR, 0.78; 95% CI, 0.64-0.95) but not with CVE risk (unadjusted HR, 0.90; 95% CI, 0.77-1.05). Compared with lower quartile PS levels, higher PS levels significantly reduced all-cause mortality (HR, 0.31; 95% CI, 0.10-1.02), and this trend remained consistent (P for trend = 0.021). Finally, the restricted cubic spline method using different models showed a linear relationship between PS and all-cause mortality (P > 0.05), when PS exceeded 4.99 kg, the all-cause mortality of MHD patients significantly decreased.

CONCLUSIONS

PS was independently associated with all-cause mortality but not with CVE in patients undergoing MHD.

Caffeic acid alleviates skeletal muscle atrophy in 5/6 nephrectomy rats through the TLR4/MYD88/NF-kB pathway

Skeletal muscle atrophy is a common complication of chronic kidney disease (CKD) that affects the quality of life and prognosis of patients. We aimed to investigate the effects and mechanisms of caffeic acid (CA), a natural phenolic compound, on skeletal muscle atrophy in CKD rats. Male Sprague-Dawley rats underwent 5/6 nephrectomy (NPM) and were treated with CA (20, 40, or 80 mg/kg/day) for 10 weeks. The body and muscle weights, renal function, hemoglobin, and albumin were measured. The histological, molecular, and biochemical changes in skeletal muscles were evaluated using hematoxylin-eosin staining, quantitative real-time PCR, malondialdehyde/catalase/superoxide dismutase/glutathione level detection, and enzyme-linked immunosorbent assay. Western blotting and network pharmacology were applied to identify the potential targets and pathways of CA, CKD, and muscle atrophy. The results showed that CA significantly improved NPM-induced muscle-catabolic effects, reduced the expression of muscle atrophy-related proteins (muscle atrophy F-box and muscle RING finger 1) and proinflammatory cytokines (interleukin [IL]-6, tumor necrosis factor-alpha, and IL-1β), and attenuated muscle oxidative stress. Network pharmacology revealed that CA modulated the response to oxidative stress and nuclear factor kappa B (NF-κB) signaling pathway and that Toll-like receptor 4 (TLR4) was a key target. In vivo experiment confirmed that CA inhibited the TLR4/myeloid differentiation primary response 88 (MYD88)/NF-kB signaling pathway, reduced muscle iron levels, and restored glutathione peroxidase 4 activity, thereby alleviating ferroptosis and inflammation in skeletal muscles. Thus, CA might be a promising therapeutic agent for preventing and treating skeletal muscle atrophy in CKD by modulating the TLR4/MYD88/NF-κB pathway and ferroptosis.

Exercise instruction during haemodialysis treatment after changes to the insurance regime: a nationwide questionnaire survey in Japan

In April 2022, an additional medical fee for exercise instruction during haemodialysis treatment was approved for insurance claims in Japan. We conducted a questionnaire survey to investigate the current situation regarding exercise therapy during haemodialysis treatment after this change. Questionnaires were mailed to 4257 haemodialysis facilities, almost all the haemodialysis facilities in Japan, on January 31, 2023. In total, 1657 facilities responded, of which 550 (33%) provided exercise instruction during haemodialysis treatment, and 65% of these claimed the new fee. Of the 550 facilities that had claimed the fee at the time of survey, 245 (55%) started exercise instruction in April 2022 or later. Exercise instruction focused on resistance training (81%) and aerobic exercise (62%) for 20-30 min (66%) three times a week (80%). The instructors included physicians in 45% of facilities, nurses in 74%, and physical therapists in 36%. Efficacy was evaluated in 76% of the facilities providing instruction, mainly by assessing change in muscle strength (49%). Overall, 39% of facilities had experienced some adverse events, but none were life-threatening. In conclusion, after the change in the insurance regime, exercise instruction during haemodialysis treatment has become more popular, and more patients on haemodialysis are undergoing exercise therapy.

Association between the oxidative balance score and low muscle mass in middle-aged US adults

Background

Oxidative Balance Score (OBS) is a tool for assessing the oxidative stress-related exposures of diet and lifestyle. The study aimed to investigate the association between OBS and low muscle mass.

Methods

Overall, 6,307 individuals over the age of 18 were assessed using data from the 2011 to 2018 National Health and Nutrition Examination Survey (NHANES). Weighted logistic regression and models were used, together with adjusted models.

Results

There was a negative relationship between OBS and low muscle mass [odds ratio (OR): 0.96, 95% confidence interval (CI): 0.94-0.97, p< 0.0001] using the first OBS level as reference. The values (all 95% CI) were 0.745 (0.527-1.054) for the second level, 0.650 (0.456-0.927) for the third level, and 0.326 (0.206-0.514) for the fourth level (P for trend <0.0001). Independent links with low muscle mass were found for diet and lifestyle factors. A restricted cubic spline model indicated a non-linear association between OBS and low muscle mass risk (P for non-linearity<0.05). In addition, the inflection points of the nonlinear curves for the relationship between OBS and risk of low muscle mass were 20.

Conclusion

OBS and low muscle mass were found to be significantly negatively correlated. By modulating oxidative balance, a healthy lifestyle and antioxidant rich diet could be a preventive strategy for low muscle mass.

Prevalence of sarcopenia in patients with chronic kidney disease: a global systematic review and meta-analysis

Sarcopenia is a risk factor for adverse clinical outcomes in chronic kidney disease (CKD) patients, including mortality. Diagnosis depends on adopted consensus definition and cutoff values; thus, prevalence rates are generally heterogeneous. We conducted a systematic review and meta-analysis to investigate the global prevalence of sarcopenia and its traits across the wide spectrum of CKD. A systematic search was conducted using databases, including MEDLINE and EMBASE, for observational studies reporting the prevalence of sarcopenia. We considered sarcopenia according to the consensus definition of the European Working Group on Sarcopenia in Older People (EWGSOP), the Asian Working Group for Sarcopenia, the Foundation for the National Institutes of Health Sarcopenia Project, and the International Working Group on Sarcopenia (IWGS). Subgroup analyses by CKD stages, consensus, and gender were performed. Pooled prevalence was obtained from random-effect models. A total of 140 studies (42 041 patients) across 25 countries were included in this systematic review and meta-analyses. Global prevalence of sarcopenia was 24.5% [95% confidence interval (CI): 20.9-28.3) and did not differ among stages (P = 0.33). Prevalence varied according to the consensus definition from 11% to 30%, with no significant difference (P = 0.42). Prevalence of severe sarcopenia was 21.0% (95% CI: 11.7-32.0), with higher rates for patients on dialysis (26.2%, 95% CI: 16.6-37.1) compared to non-dialysis (3.0%, 95% CI: 0-11.1; P < 0.01). Sarcopenic obesity was observed in 10.8% (95% CI: 3.5-21.2). Regarding sarcopenia traits, low muscle strength was found in 43.4% (95%CI: 35.0-51.9), low muscle mass in 29.1% (95% CI: 23.9-34.5), and low physical performance in 38.6 (95% CI: 30.9-46.6) for overall CKD. Prevalence was only higher in patients on dialysis (50.0%, 95% CI: 41.7-57.4) compared to non-dialysis (19.6%, 95% CI: 12.8-27.3; P < 0.01) for low muscle strength. We found a high global prevalence of sarcopenia in the wide spectrum of CKD. Low muscle strength, the primary sarcopenia trait, was found in almost half of the overall population with CKD. Patients on dialysis were more prevalent to low muscle strength and severe sarcopenia. Nephrology professionals should be aware of regularly assessing sarcopenia and its traits in patients with CKD, especially those on dialysis.

Serum Myostatin at Dialysis Initiation May Predict 1-Year Mortality and Hospitalization

OBJECTIVE

Myostatin, which is known as a negative skeleton muscle regulator, is associated with mortality in maintenance hemodialysis patients. However, the significance of serum myostatin concentrations at dialysis initiation has not been established. We investigated the relation between serum myostatin concentrations and mortality or hospitalization within 1 year in incident dialysis patients.

METHODS

After a patient initiating hemodialysis or peritoneal dialysis during 2016-2018 was enrolled, the patient's serum myostatin at dialysis initiation was measured. Composite outcomes comprising mortality and hospitalization within 1 year after dialysis initiation were compared between two groups divided according to myostatin levels. The Cox proportional hazards model was used to assess significant relations between myostatin and outcomes.

RESULTS

This study examined 104 incident dialysis patients with a mean age of 65.5 ± 14.0 years (68% male). Kaplan-Meier analyses indicated the 1-year hospitalization-free and survival rate as significantly lower in the lower myostatin group than in the higher myostatin group (p = 0.0020). Cox proportional hazards regression analyses revealed that the value of myostatin logarithm at dialysis initiation was inversely associated with the occurrence of a composite outcome, independently of age (hazard ratio 0.16, 95% confidence interval: 0.05-0.57). Receiver operating characteristic analysis showed the area under the curve of serum myostatin for predicting death or hospitalization within 1 year as higher than those of clinical indices of nutritional disturbance and frailty.

CONCLUSION

Serum myostatin concentration at dialysis initiation is inversely associated with adverse outcomes in these dialysis-initiated patients.

Association between sarcopenic obesity and mortality in patients on peritoneal dialysis: a prospective cohort study

Background

Whether sarcopenic obesity had unfavorable effect on survival of peritoneal dialysis (PD) patients is unknown. We aimed to investigate the association between sarcopenic obesity and survival in PD patients.

Methods

This was a prospective observational study. Eligible PD patients from November 2016 to December 2017 were enrolled and followed until August 31, 2023. Sarcopenia was defined following the recommendations of the Asian Working Group for Sarcopenia (AWGS) as low appendicular skeletal muscle mass index (ASMI) and handgrip strength (HGS). Obesity was defined using the percentage of body fat (PBF). Survival analysis was conducted using the Kaplan-Meier and log-rank test. The Cox regression and the cumulative incidence competing risk (CICR) analyzes were used to investigate the association between sarcopenic obesity and all-cause mortality.

Results

A total of 223 patients were enrolled with 133 (59.6%) males, a median age of 57.5 (44.6, 65.7) years, a median dialysis vintage of 20.3 (6.4, 57.7) months and 48 (21.5%) who had comorbid diabetes mellitus. Among them, 46 (20.6%) patients were sarcopenic, and 25 (11.2%) patients were diagnosed with sarcopenic obesity. After followed up for 51.6 (25.6, 73.9) months, the Kaplan-Meier curve showed the sarcopenic obesity (log-rank = 13.527, p < 0.001) group had significant lower survival rate compared to the nonsarcopenic non-obesity group. For multivariate analysis, the CICR method showed patients with sarcopenic obesity had significantly higher mortality rate (HR: 2.190, 95% CI: 1.011-4.743, p = 0.047) compared to those with nonsarcopenic non-obesity.

Conclusion

Sarcopenia is not uncommon in PD patients, with a considerable proportion having sarcopenic obesity. There is a significant association between sarcopenic obesity and an increased risk of mortality in PD patients.

Nutritional Considerations for Patients With Renal Failure Undergoing Sleeve Gastrectomy

Obesity is highly prevalent in patients with renal disease, as it contributes to or accelerates the progression of kidney disease and is frequently a barrier to kidney transplantation. Patients with renal disease have unique dietary needs due to various metabolic disturbances resulting from altered processing and clearance of nutrients. They also frequently present with physical disability, resulting in difficulty achieving adequate weight loss through lifestyle modifications. Therefore, kidney transplant candidates may benefit from bariatric surgery, particularly sleeve gastrectomy (SG), as the safest, most effective, and long-lasting weight loss option to improve comorbidities and access to transplantation. However, concerns regarding nutritional risks prevent broader dissemination of SG in this population. No specific guidelines tailored to the nutritional needs of patients with renal disease undergoing SG have been developed. Moreover, appropriate monitoring strategies and interventions for muscle loss and functional status preservation, a major concern in this at-risk population, are unknown. We aimed to summarize the available literature on the nutritional requirements of patients with renal disease seeking SG as a bridge to transplantation. We also provide insight and guidance into the nutritional management pre and post-SG.

Identification of molecular mediators of renal sarcopenia risk: a mendelian randomization analysis

BACKGROUND

Observational studies have shown an association between reduced renal function and the risk of sarcopenia. However, the causal relationship and the underlying biological mechanisms remain uncertain. Using a Mendelian randomization (MR) framework, we investigated the causal role of 27 hypothetical risk mediators, including metabolites, hormones, inflammation, and stress traits, on the risk of sarcopenia.

METHODS

Instrumental variables (IVs) to proxy renal function were identified by selecting single nucleotide polymorphisms (SNPs) reliably associated with creatinine and cystatin C-based glomerular filtration rate (GFR) in CKDGen summary data. IVs for putative risk traits and sarcopenia traits were constructed from relevant genome-wide association studies (GWAS). MR estimated effects were obtained using an inverse-variance weighted effects model, and various sensitivity analyses were performed. The mediating role of hypothetical risk factors in the relationship between GFR and sarcopenia was assessed through multivariate MR.

RESULTS

Genetically predicted reduced GFRcrea was associated with higher odds of appendicular lean mass (ALM) (odds ratio (OR): 0.64, 95% confidence interval (CI) 0.37 to 0.68) and grip strength (OR: 0.67; 95% CI 0.58 to 0.78). Likewise, GFRcys highlighted a causal relationship with ALM (OR: 0.52; 95% CI 0.42 to 0.65) and grip strength (OR: 0.66; 95% CI 0.59 to 0.74). Both estimated GFR (eGFR) were negatively associated with IGF-1, IL-16, 25(OH)D, triglycerides (range of effect size per standard deviation: -0.81 to -0.30), and positively correlated with HDL cholesterol (0.62, 0.31). There was a positive correlation between IGF-1, fasting insulin and ALM as well as grip strength (OR range: 1.04-1.67) and a negative correlation between serum CRP and ALM (OR: 0.95) as well as grip strength (OR: 0.98). Additionally, genetically predicted IL-1β (OR: 0.95) and total cholesterol (OR: 0.96) were negatively associated with ALM. We found evidence that IGF-1 mediates the relationship between eGFR and risk for muscle mass and strength.

CONCLUSIONS

This MR study provides insight into the potential causal mechanisms between renal function and the risk of sarcopenia and proposes IGF-1 as a potential target for the prevention of renal sarcopenia.

Nutritional Assessments by Bioimpedance Technique in Dialysis Patients

Bioelectrical impedance analysis (BIA) has been extensively applied in nutritional assessments on the general population, and it is recommended in establishing the diagnosis of malnutrition and sarcopenia. The bioimpedance technique has become a promising modality through which to measure the whole-body composition in dialysis patients, where the presence of subclinical volume overload and sarcopenic obesity may be overlooked by assessing body weight alone. In the past two decades, bioimpedance devices have evolved from applying a single frequency to a range of frequencies (bioimpedance spectroscopy, BIS), in which the latter is incorporated with a three-compartment model that allows for the simultaneous measurement of the volume of overhydration, adipose tissue mass (ATM), and lean tissue mass (LTM). However, clinicians should be aware of common potential limitations, such as the adoption of population-specific prediction equations in some BIA devices. Inherent prediction error does exist in the bioimpedance technique, but the extent to which this error becomes clinically significant remains to be determined. Importantly, reduction in LTM has been associated with increased risk of frailty, hospitalization, and mortality in dialysis patients, whereas the prognostic value of ATM remains debatable. Further studies are needed to determine whether modifications of bioimpedance-derived body composition parameters through nutrition intervention can result in clinical benefits.

Association between sarcopenia with incident cardio-cerebrovascular disease: A systematic review and meta-analysis

Sarcopenia is an age-associated skeletal muscle disease characterized by the progressive loss of muscle mass and function. The objective of this systematic review and meta-analysis was to evaluate the associations between sarcopenia and cardio-cerebrovascular disease (CCVD). A comprehensive search of the PubMed/Medline, Embase, Web of Science, Scopus, and Cochrane Library databases was conducted from their inception to April 1st, 2023. A total of eight cross-sectional studies involving 63,738,162 participants met the inclusion criteria. Pooled estimates of odds ratios (ORs) were calculated using random-effects models. The findings demonstrated a significant association between sarcopenia and an increased risk of CCVD (OR: 1.33, 95% CI: 1.18 - 1.50, I2 = 1%; p < 0.001). Subgroup analyses indicated that sarcopenia was associated with a 1.67-fold increase in the risk of stroke and a 1.31-fold increase in the risk of CVD. Four studies included in this review examined the association between sarcopenic obesity and the risk of CCVD, and the results revealed that sarcopenic obesity was associated with a higher risk of CCVD (OR: 1.64, 95% CI: 1.08 - 2.49, I2 = 69%; p < 0.001). Meta-regressions and sensitivity analyses consistently supported the robustness of the overall findings. In conclusion, sarcopenia and sarcopenic obesity are significantly associated with an elevated risk of developing CCVD. However, further prospective cohort studies are warranted to validate this relationship while controlling for confounding factors.

The Association between Serum Creatinine/Cystatin C Ratio and Cardiovascular Morbidity and Mortality: Insights from NHANES

Background

The Serum creatinine/cystatin C ratio (Cr/CysC ratio) is an emerging alternative index for muscle mass loss, a risk factor for cardiovascular diseases (CVDs). However, the association between the Cr/CysC ratio and CVD morbidity and mortality remains unknown.

Methods

A total of 11,150 participants of the National Health and Nutrition Examination Survey (NHANES) were included in this study. Univariable and multivariable logistic regression models were employed to assess the association between the Cr/CysC ratio and self-reported CVD morbidity. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95% confidence interval (CI) of the Cr/CysC ratio for CVD mortality.

Results

At baseline, 1181 (7.90%) participants had self-reported CVDs. Lower Cr/CysC ratios were found in participants with CVDs (1.18 ± 0.30 vs. 1.05 ± 0.23, p < 0.001). In the multivariable logistic regression model, the Cr/CysC ratio was inversely linked to CVD morbidity (odds ratio: 0.65, 95% CI: 0.52-0.81, p < 0.001, per standard deviation [SD] increase). 997 (8.94%) CVD deaths were documented during a median follow-up of 16.9 years. A higher Cr/CysC ratio was associated with a decreasing risk of CVD mortality (adjusted HR: 0.54, 95% CI: 0.46-0.65, p < 0.001, per SD increase).

Conclusions

In NHANES participants, the Cr/CysC ratio had an inverse correlation with CVD morbidity and mortality.

Intradialytic neuromuscular electrical stimulation with optional virtual reality distraction improves not only muscle strength and functional capacity but also serum albumin level in haemodialysis patients: a pilot randomized clinical trial

BACKGROUND

Sarcopenia is highly prevalent in haemodialysis (HD) patients and linked to a poor prognosis regarding comorbidities and premature mortality. Previous studies assessed the effects of neuromuscular electrical stimulation in haemodialysis patients. This study adds to the relevance of neuromuscular electrical stimulation (NMES) applications combined with a virtual reality (VR) distraction to increase intensity, dosage, and efficiency of NMES and slow sarcopenia progression in HD patients.

METHODS

We conducted a 12-week multicenter prospective randomised controlled trial. The patients were randomly assigned to one of the three groups: neuromuscular electrical stimulation with or without combined virtual reality distraction or control group.

RESULTS

The final analysis included 32 haemodialysis patients (mean age of 68 ± 10 years, 26 men). Interaction effects between groups and time (12 weeks) were significant regarding serum albumin levels (p = 0.008) and left quadriceps femoris muscle (QFM) force (p = 0.026). Both endpoints were increased in the NMES compared to the CO group at the end of the intervention. The NMES group increased serum albumin levels significantly after 12 weeks. The main effect of time was an increase in mean right QFM force between beginning and end of the intervention (p = 0.021). Functional capacity improved after 12 weeks in the NMES and NMES + VR but not in the control group, with a significant difference between the three groups (p = 0.022). Weight and body mass index increased in the NMES and NMES + VR groups, albeit not significantly. The effects of VR distraction on NMES efficiency were inconclusive.

CONCLUSION

Intradialytic NMES increases serum albumin level, functional capacity, muscle strength in lower limb and in tendency weight and body mass index of HD patients. Effects on VR distraction are inconclusive. Large-scaled follow-up studies on integrated sports programs with NMES and active training in combination with VR as distraction and motivation accelerator are needed.

TRIAL REGISTRATION

German Clinical Trial Register: DRKS00029276 (Retrospectively registered: 30/06/2022).

Clinical features and molecular mechanism of muscle wasting in end stage renal disease

Muscle wasting in end-stage renal disease (ESRD) is an escalating issue due to the increasing global prevalence of ESRD and its significant clinical impact, including a close association with elevated mortality risk. The phenomenon of muscle wasting in ESRD, which exceeds the rate of muscle loss observed in the normal aging process, arises from multifactorial processes. This review paper aims to provide a comprehensive understanding of muscle wasting in ESRD, covering its epidemiology, underlying molecular mechanisms, and current and emerging therapeutic interventions. It delves into the assessment techniques for muscle mass and function, before exploring the intricate metabolic and molecular pathways that lead to muscle atrophy in ESRD patients. We further discuss various strategies to mitigate muscle wasting, including nutritional, pharmacological, exercise, and physical modalities intervention. This review seeks to provide a solid foundation for future research in this area, fostering a deeper understanding of muscle wasting in ESRD, and paving the way for the development of novel strategies to improve patient outcomes. [BMB Reports 2023; 56(8): 426-438].

Clinical features and molecular mechanism of muscle wasting in end stage renal disease

Muscle wasting in end-stage renal disease (ESRD) is an escalating issue due to the increasing global prevalence of ESRD and its significant clinical impact, including a close association with elevated mortality risk. The phenomenon of muscle wasting in ESRD, which exceeds the rate of muscle loss observed in the normal aging process, arises from multifactorial processes. This review paper aims to provide a comprehensive understanding of muscle wasting in ESRD, covering its epidemiology, underlying molecular mechanisms, and current and emerging therapeutic interventions. It delves into the assessment techniques for muscle mass and function, before exploring the intricate metabolic and molecular pathways that lead to muscle atrophy in ESRD patients. We further discuss various strategies to mitigate muscle wasting, including nutritional, pharmacological, exercise, and physical modalities intervention. This review seeks to provide a solid foundation for future research in this area, fostering a deeper understanding of muscle wasting in ESRD, and paving the way for the development of novel strategies to improve patient outcomes. [BMB Reports 2023; 56(8): 426-438].