Both low muscle mass and low fat are associated with higher all-cause mortality in hemodialysis patients

Association of sarcopenia defined by different skeletal muscle mass measurements with prognosis and quality of life in older patients with heart failure

BACKGROUND

Diagnosing sarcopenia in heart failure (HF) patients is important, but how to assess skeletal muscle mass in HF patients with fluid retention is controversial. We aimed to examine the association between sarcopenia, defined by different skeletal muscle mass measurements, and clinical outcomes in older HF patients.

METHODS

We included 546 older HF patients (≥ 65 years) who were assessed for sarcopenia at discharge (median age 77 years, 309 males). Sarcopenia was diagnosed using grip strength, usual gait speed, and skeletal muscle mass according to international criteria. We used mid-upper arm circumference (MUAC), mid-upper arm muscle circumference (MAMC), calf circumference (CC), and skeletal muscle mass index (SMI) assessed by bioelectrical impedance analysis to assess skeletal muscle mass and defined sarcopenia in each of these measurements. Prognostic outcomes were composite events (all-cause death and HF rehospitalization) and cardiovascular disease (CVD) events (CVD death and CVD rehospitalization). Quality of life (QOL) was assessed using the 36-item Short-Form Health Survey physical functioning (SF-36PF) score.

RESULTS

The sarcopenia defined by MUAC [hazard ratio (HR): 2.50; 95 % confidence interval (95 % CI): 1.64-3.81; p < 0.001] or MAMC (HR: 1.98; 95 % CI: 1.35-2.92; p = 0.001) were associated with higher composite event rates than the non-sarcopenia. The sarcopenia defined by MUAC (HR: 1.88; 95 % CI: 1.25-2.83; p = 0.002) or MAMC (HR: 1.70; 95 % CI: 1.16-2.49; p = 0.007) were associated with higher CVD event rates than the non-sarcopenia. The sarcopenia defined by CC or SMI were not associated with prognoses. The sarcopenia defined by MUAC, MAMC, or CC were associated with low SF-36PF scores (all p < 0.05).

CONCLUSIONS

These results suggest that a diagnosis of sarcopenia based on MUAC or MAMC rather than CC or SMI reflects prognosis and QOL in older HF patients.

Trajectory of mid-arm subcutaneous fat, muscle mass predicts mortality in hemodialysis patients independent of body mass index

Although decreasing body mass index (BMI) is associated with higher mortality risk in patients undergoing hemodialysis (HD), BMI neither differentiates muscle and fat mass nor provides information about the variations of fat distribution. It remains unclear whether changes over time in fat and muscle mass are associated with mortality. We examined the prognostic significance of trajectory in the triceps skinfold (TSF) thickness and mid-upper arm circumference (MUAC). In this multicenter prospective cohort study, 972 outpatients (mean age, 54.5 years; 55.3% men) undergoing maintenance HD at 22 treatment centers were included. We calculated the relative change in TSF and MUAC over a 1-year period. The outcome was all-cause mortality. Kaplan-Meier, Cox proportional hazard analyses, restricted cubic splines, and Fine and Gray sub-distribution hazards models were performed to examine whether TSF and MUAC trajectories were associated with all-cause mortality. During follow-up (median, 48.0 months), 206 (21.2%) HD patients died. Compared with the lowest trajectory group, the highest trajectories of TSF and MUAC were independently associated with lower risk for all-cause mortality (HR = 0.405, 95% CI 0.257-0.640; HR = 0.537; 95% CI 0.345-0.837; respectively), even adjusting for BMI trajectory. Increasing TSF and MUAC over time, measured as continuous variables and expressed per 1-standard deviation decrease, were associated with a 55.7% (HR = 0.443, 95% CI 0.302-0.649), and 97.8% (HR = 0.022, 95% CI 0.005-0.102) decreased risk of all-cause mortality. Reduction of TSF and MUAC are independently associated with lower all-cause mortality, independent of change in BMI. Our study revealed that the trajectory of TSF thickness and MUAC provides additional prognostic information to the BMI trajectory in HD patients.

Triceps skinfold thickness trajectories and the risk of all-cause mortality: A prospective cohort study

BACKGROUND

The measurement of triceps skinfold (TSF) thickness serves as a noninvasive metric for evaluating subcutaneous fat distribution. Despite its clinical utility, the TSF thickness trajectories and their correlation with overall mortality have not been thoroughly investigated.

AIM

To explore TSF thickness trajectories of Chinese adults and to examine their associations with all-cause mortality.

METHODS

This study encompassed a cohort of 14747 adults sourced from the China Health and Nutrition Survey. Latent class trajectory modeling was employed to identify distinct trajectories of TSF thickness. Subjects were classified into subgroups reflective of their respective TSF thickness trajectory. We utilized multivariate Cox regression analyses and mediation examinations to explore the link between TSF thickness trajectory and overall mortality, including contributory factors.

RESULTS

Upon adjustment for multiple confounding factors, we discerned that males in the 'Class 2: Thin-stable' and 'Class 3: Thin-moderate' TSF thickness trajectories exhibited a markedly reduced risk of mortality from all causes in comparison to the 'Class 1: Extremely thin' subgroup. In the mediation analyses, the Geriatric Nutritional Risk Index was found to be a partial intermediary in the relationship between TSF thickness trajectories and mortality. For females, a lower TSF thickness pattern was significantly predictive of elevated all-cause mortality risk exclusively within the non-elderly cohort.

CONCLUSION

In males and non-elderly females, lower TSF thickness trajectories are significantly predictive of heightened mortality risk, independent of single-point TSF thickness, body mass index, and waist circumference.

Gut microbiota associations with chronic kidney disease: insights into nutritional and inflammatory parameters

Introduction

The gut barrier, comprising gut microbiota, plays a pivotal role in chronic kidney disease (CKD) progression and nutritional status. This study aimed to explore gut barrier alterations in hemodialyzed (HD) patients, non-HD (NHD) CKD patients, and healthy volunteers.

Methods

Our cross-sectional study enrolled 22 HD patients, 11 NHD patients, and 11 healthy volunteers. We evaluated fecal microbiota composition (assessed via bacterial 16S rRNA gene sequencing), fecal IgA levels, surrogate markers of gut permeability, serum cytokines, appetite mediators, nutritional status, physical activity, and quality of life.

Results

HD patients exhibited significant alterations in fecal microbiota composition compared to healthy volunteers, with observed shifts in taxa known to be associated with dietary patterns or producing metabolites acting on human host. In comparison to healthy volunteers, individuals with HD patients exhibited elevated levels of inflammatory markers (CRP, IL-6 and TNF-α), glucagon-like peptide-2, and potential anorexigenic markers (including leptin and peptide YY). NHD patients had increased levels of CRP and peptide YY. Overall fecal microbiota composition was associated with height, soft lean mass, resting energy expenditure, handgrip strength, bone mineral content and plasma albumin and TNF-α.

Discussion

Compared to healthy volunteers, HD patients have an altered fecal microbiota composition, a higher systemic inflammation, and a modification in plasma levels of appetite mediators. While some differences align with previous findings, heterogeneity exists likely due to various factors including lifestyle and comorbidities. Despite limitations such as sample size, our study underscores the multifaceted interplay between gut microbiota, physiological markers, and kidney function, warranting further investigation in larger cohorts.

Fat tissue quantity, waist circumference or waist-to-hip ratio in patients with chronic kidney disease: A systematic review and meta-analysis

The BMI predicts mortality and cardiovascular disease (CVD) in the general population, while in patients with end-stage chronic kidney disease (CKD) a high BMI is associated with improved survival, a phenomenon referred to as the "obesity paradox". While BMI is easy to determine and helps to categorize patients, it does not differentiate between fat tissue, lean tissue and bone mass. As the BMI may be altered in CKD, e.g. by muscle wasting, we determined in this meta-analysis (i) the association of mortality with fat tissue quantity in CKD and (ii) the association of mortality with abdominal obesity (as measured by waist circumference (WC) or waist-to-hip ratio (WHR)) in CKD. We systematically reviewed databases for prospective or retrospective cohort studies. In eleven studies with 23,523 patients the association between mortality and high fat tissue quantity in CKD was calculated. The pooled hazard ratio (HR) for this association in the CKD group in the dialysis group 0.91 (CI 0.84- 0.98, p = 0.01) which is comparable to the HR for the association with BMI. The HR in patients without dialysis was 0.7 (95% CI 0.53- 0.93, p = 0.01), suggesting a better risk prediction of high fat tissue content with mortality as compared to higher BMI with mortality in patients with CKD without dialysis. Importantly, both BMI and fat tissue quantity in CKD are described by the "obesity paradox": the higher the fat tissue content or BMI, the lower the mortality risk. In thirteen studies with 55,175 patients the association between mortality and high WC or WHR in CKD (with or without dialysis) was calculated. We observed, that the HR in the WHR group was 1.31 (CI 1.08-1.58, p = 0.007), whereas the overall hazard ratio of both groups was 1.09 (CI 1.01-1.18, p = 0.03), indicating that a higher abdominal obesity as measured by WHR is associated with higher mortality in CKD. Our analysis suggests gender-specific differences, which need larger study numbers for validation. This meta-analysis confirms the obesity paradox in CKD using fat tissue quantity as measure and further shows that using abdominal obesity measurements in the routine in obese CKD patients might allow better risk assessment than using BMI or fat tissue quantity. Comparable to the overall population, here, the higher the WHR, the higher the mortality risk.

Intramuscular and abdominal fat measured by computed tomography and mortality of hemodialysis patients

BACKGROUND

In hemodialysis patients, high body mass index is associated with low mortality while abdominal obesity relates to increased mortality. We aimed to investigate the association between muscle mass, intramuscular fat and abdominal fat measured by abdominal computed tomography (CT), and mortality in this patients population.

METHODS

This two-center retrospective cohort study included hemodialysis patients who underwent abdominal CT between January 2013 and December 2018. Skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and visceral fat to subcutaneous fat ratio (VSR) were calculated using CT images at the third lumbar vertebral level. Multivariate Cox proportional hazards model was used to determine the independent predictors of all-cause, cardiovascular and non-cardiovascular mortalities.

RESULTS

The study included 344 patients (median age 71.0 years; female 33.7%), among whom 145 died during a median follow-up of 4.9 years-46 and 99 from cardiovascular and non-cardiovascular causes, respectively. Lower MRA [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.87, P = .001] and higher VSR (HR 1.17, 95% CI 1.01-1.37, P = .04) were independently associated with higher all-cause mortality but not with lower SMI (HR 0.87, 95% CI 0.68-1.11, P = .26). Lower MRA (HR 0.51, 95% CI 0.35-0.73, P < .001) and higher VSR (HR 1.29, 95% CI 1.09-1.54, P = .003) were also associated with cardiovascular and non-cardiovascular mortality, respectively.

CONCLUSIONS

Intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.

Mid-arm muscle circumference and triceps skinfold thickness associated with cardiometabolic disease in Chinese residents: A prospective cohort study

BACKGROUND AND AIMS

The association of cardiometabolic disease (CMD) with body muscle and fat mass remains unclear. Mid-arm muscle circumference (MAMC) and triceps skinfold (TSF) thickness are easily obtained measuring methods for these two body compositions. This study aimed to investigate the association of CMD with MAMC and TSF thickness among Chinese residents.

METHODS

A total of 9440 eligible participants from the China Health and Nutrition Survey were included in the analysis. Associations of CMD prevalence with MAMC and TSF thickness were estimated using logistic regression models. Multivariable COX proportional-hazards regression models were used to estimate the effect of baseline MAMC and TSF thickness on subsequent CMD.

RESULTS

Positive associations of CMD prevalence with MAMC (odds ratio [OR] = 1.169, 95% confidence interval [CI] 1.110-1.232, P < 0.001) and TSF thickness (OR = 1.313, 95%CI 1.240-1.390, P < 0.001) were observed in the cross-sectional analysis. In the longitudinal study, a 1-SD increase in MAMC was associated with a 13.6% increased risk of CMD incidence (hazard ratio [HR] = 1.136, 95%CI 1.073-1.204, P < 0.001), and a 1-SD increase in TSF thickness had a 17.6% increased risk of CMD incidence (HR = 1.176, 95%CI 1.084-1.276, P < 0.001). For the CMD components, both MAMC and TSF thickness contributed to increased incidences of hypertension (HR = 1.163, 95%CI 1.097-1.233, P < 0.001 in MAMC; HR = 1.218, 95%CI 1.110-1.336, P < 0.001 in TSF thickness) and diabetes mellitus (HR = 1.166, 95%CI 1.028-1.323, P = 0.017 in MAMC; HR = 1.352, 95%CI 1.098-1.664, P = 0.004 in TSF thickness).

CONCLUSIONS

Individuals with higher MAMC and TSF thickness had an increased incidence of CMD, mainly hypertension and diabetes mellitus. This study revealed a seemingly counterintuitive association between body muscle mass and metabolic homeostasis. Although the potential mechanisms require further exploration, the impact of body muscle mass on metabolic health cannot be ignored.

The relationship between skeletal muscle mass and exercise capacity in patients undergoing hemodialysis: An exploratory secondary-analysis

BACKGROUND

Protein-energy wasting is commonly observed in patients undergoing hemodialysis, leading to reduced muscle mass and, in severe cases, sarcopenia, which significantly impacts the patients' quality of life and clinical outcomes. Exercise interventions are frequently employed to address muscle loss in these patients. However, the relationship between exercise capacity and skeletal muscle mass in this context remains uncertain. In this study, researchers conducted a series of body composition analysis and exercise capacity test to explore the relationship between exercise capacity and skeletal muscle mass.

METHODS

This study recruited 32 patients undergoing hemodialysis and analyzed their demographic and clinical parameters. To assess aerobic exercise capacity, the incremental shuttle walking test (ISWT) was conducted, while the handgrip strength test was used to evaluate muscle strength. The patients' body compositions were assessed using the Fresenius Body Composition Monitor, and the appendicular skeletal muscle was scanned using a GE Healthcare Lunar iDXA scanner. Three sequential linear models were employed to model the relationship between ISWT and skeletal muscle mass. Model 1 regressed ISWT against gender and age; Model 2 added handgrip strength, fat tissue index, and Davies comorbidity scores as additional predictors; and Model 3 further included the appendicular skeletal muscle index (appendicular skeletal muscle/height).

FINDINGS

After controlling for age and gender (Model 1: R2  = 0.373), and subsequently including handgrip strength, fat tissue index, and Davies comorbidity score effects (Model 2: R2  = 0.581), the impact of appendicular skeletal muscle on ISWT was found to be non-significant (Model 3: R2  = 0.600).

CONCLUSION

There was no significant correlation observed between exercise capacity and skeletal muscle mass in patients undergoing hemodialysis, indicating the factors influencing exercise capacity in this patient population are complex and that increasing skeletal muscle mass may not necessarily involve solely addressing the improvement of exercise capacity.

The body mass index change is associated with death or hemodialysis transfer in Japanese patients initiating peritoneal dialysis

A decreased body mass index (BMI) over time is associated with a poor prognosis for patients on hemodialysis. We aimed to examine whether this association also applies to patients with peritoneal dialysis (PD). BMI change was defined as the percentage change in the BMI between the time of PD catheter insertion and six months after its insertion. The association between the BMI change and all-cause mortality or PD discontinuation from six months after PD catheter insertion until October 2021 was investigated. This retrospective cohort study included 122 patients (aged 61.1 ± 12.1 years; 90 males) who underwent PD catheter insertion between January 2008 and March 2020. The median follow-up period was 43.1 (21.2-78.8) months. The median six-month percentage change in the BMI was -2.14 (-5.56-1.84)%, and patients were categorized into tertiles based on their BMI changes. The fully-adjusted Cox regression analysis revealed a significantly higher rate of PD discontinuation or all-cause mortality (hazard ratio (HR): 2.48; 95%; confidence interval (CI): 1.41-4.37) in patients with the lowest tertile (T1, BMI change: < -4.13%) compared to patients with the middle tertile (T2, BMI change: -4.13%-0.67%). The risk was not significantly higher in patients with the highest tertile (T3, BMI change: >0.67%) than those in the T2 group (HR: 1.18; 95% CI: 0.66-2.11). A decreased BMI over time is independently associated with HD transfer or all-cause mortality among patients initiating PD, which highlights the importance of the 6-month BMI change as a novel prognostic marker.

Klotho and lean mass as novel cardiovascular risk factors in hemodialysis patients

Background

Patients with chronic kidney disease (CKD) present a higher risk of cardiovascular (CV) morbidity and mortality compared with the general population. While there are several well-established traditional CV risk factors, few studies have addressed novel potential risk factors such as α-Klotho, asymmetric dimethylarginine (ADMA) and lean mass.

Methods

This was an observational, prospective, single-center, cohort study that included prevalent hemodialysis (online hemodiafiltration) adult patients. By univariate logistic regression models, univariate and multivariate Cox proportional hazards models, and Kaplan-Meier analysis, we evaluated the association between the levels of α-Klotho, ADMA and lean mass, with the risk of peripheral vascular disease (PVD), CV events and all-cause mortality in these patients.

Results

A total of 200 HD patients was included. We found that increased levels of log-α-Klotho were significantly associated with decreased odds of both PVD [odds ratio (OR) 0.521, 95% confidence interval (CI) 0.270-0.954, P = .034] and CV events (OR 0.415, 95% CI 0.203-0.790, P = .01), whereas increased levels of log-ADMA were only significantly associated with increased odds of PVD (OR 13.482, 95% CI 5.055-41.606, P < .001). We also found that the levels of log-α-Klotho (HR 0.357, 95% CI 0.140-0.906, P < .05) and lean mass (HR 0.187, 95% CI 0.042-0.829, P < .05), but not log-ADMA, were significantly associated with the risk of all-cause mortality, even after adjusting for possible confounding variables.

Conclusions

Novel long-term clinical associations were generated that support α-Klotho and lean mass as novel CV risk factors in hemodialysis patients.

Low Lean Tissue Index and Muscle Strength Combined with High Fat Tissue Index Are Associated with Cardiovascular Disease-Related Hospitalisation in Patients on Haemodialysis

INTRODUCTION

The combined clinical impact of muscle mass, muscle function, and adipose mass on hospitalisation events, especially those that have exact causes, such as cardiovascular diseases (CVDs), had been rarely studied in patients on haemodialysis (HD). This study aimed to determine the influence of lean tissue index (LTI), fat tissue index (FTI), and hand grip strength (HGS) on the risk of CVD-related hospitalisation in patients undergoing chronic HD.

METHODS

This multi-centre observational study enrolled a total of 2,041 clinically stable patients aged >18 years and who had undergone HD for at least 3 months at 17 HD units in 2019. The follow-up period was up to 2 years. LTI and FTI were assessed using a body composition monitoring machine, and HGS was measured by a CAMRY® dynamometer. Cox regression models were fit to estimate the associations of body composition and HGS with CVD-related hospitalisation risk.

RESULTS

During a mean follow-up of 22.6 months, CVD-related hospitalisation occurred in 492 patients. Compared with the non-CVD group, patients with CVD-related hospitalisation were older; had lower diastolic blood pressure; were more likely to have a history of diabetes; had worse activity status scores and lower levels of LTI, HGS, serum uric acid, and serum creatinine; and had higher FTI levels, body mass index, and extracellular water/intracellular water ratio. In the Cox regression models, low LTI and high FTI were independently associated with CVD-related hospitalisation in both men and women. In men, low HGS was an independent risk factor for CVD-related hospitalisation. When patients were further stratified into four distinct groups according to the sex-specific median values of LTI and FTI, the combination of low LTI and high FTI was an independent risk factor for CVD-related hospitalization (hazard ratio [HR] = 1.79 in men, 95% confidence interval 1.26-2.55; HR = 2.48 in women, 95% confidence interval 1.66-3.71; reference: high LTI/low FTI group).

CONCLUSIONS

Among patients on chronic HD, low LTI, and high FTI were associated with CVD-related hospitalisation in men and women, whereas HGS was an independent risk factor for CVD-related hospitalisation in men but not in women. Combining low LTI and high FTI increased the association with hospitalisation risk and was an independent predictor of CVD-related hospitalisation.

Effects of anthropometric changes on hospitalization and mortality among patients on hemodialysis

BACKGROUND

Low values for anthropometric indicators are risk factors for adverse clinical outcomes among patients on hemodialysis. Nonetheless, little is known about the association between the trajectory of anthropometric indicators and prognosis. We examined the association between a one-year change in anthropometric indicators and hospitalization and mortality in patients undergoing hemodialysis.

METHODS

This retrospective cohort study collected data on five anthropometric indicators from patients undergoing maintenance hemodialysis: body mass index, mid-upper arm circumference, triceps skinfold, mid-arm muscle circumference, and calf circumference. We calculated their trajectories over one year. The outcomes were all-cause death and the number of all-cause hospitalizations. Negative binomial regressions were used to examine these associations.

RESULTS

We included 283 patients (mean age, 67.3 years; 60.4% males). During the follow-up period (median, 2.7 years), 30 deaths and 200 hospitalizations occurred. Body mass index (incident rate ratio [IRR]: 0.87; 95% confidence interval [CI] 0.85-0.90), mid-upper arm circumference (IRR: 0.94; 95% CI 0.88-0.99), triceps skinfold (IRR: 0.92; 95% CI 0.84-0.99), and mid-arm muscle circumference (IRR: 0.99; 95% CI 0.98-0.99) increases over one year were associated with a lower risk of all-cause hospitalizations and death regardless of their value at any one point in time. However, the calf circumference trajectory was not associated with clinical events (IRR: 0.94; 95% CI 0.83-1.07).

CONCLUSIONS

Body mass index, mid-upper arm circumference, triceps skinfold, and mid-arm muscle circumference trajectories were independently associated with clinical events. Routinely assessing these simple measures in clinical practice may provide additional prognostic information for managing patients undergoing hemodialysis.

Post-discharge consequences of protein-energy malnutrition, sarcopenia, and frailty in older adults admitted to rehabilitation: A systematic review

BACKGROUND & AIMS

Malnutrition, sarcopenia, and frailty are three prevalent wasting conditions among older rehabilitation patients that lead to multiple health-related negative outcomes. This systematic review and meta-analysis aimed to determine the post-discharge consequences of malnutrition, sarcopenia, and frailty in older adults admitted to inpatient rehabilitation.

METHODS

MEDLINE, Embase, Web of Science, and CINAHL databases were searched on 20 April, 2021 for longitudinal studies in older adults (≥65 years) admitted for inpatient rehabilitation. This systematic review included and synthesised studies that 1) measured malnutrition, sarcopenia, and/or frailty using a validated assessment tool or guideline; and 2) reported the association with post-discharge mortality, physical function, quality of life, or discharge location. The Academy of Nutrition & Dietetics Quality Criteria Checklist and GRADE criteria were used to assess risk of bias and evidence certainty. Where possible, data were pooled using Revman.

RESULTS

Twenty-six observational studies (n = 9709 participants in total) with similarly aged populations were included. Eight, seven, and eleven studies assessed malnutrition, sarcopenia, and frailty, respectively. Follow-up periods ranged from immediate to 7 years post-rehabilitation. Malnutrition was associated with discharge to a higher level of care (GRADE: very low), and worse quality of life (GRADE: very low) and physical function (GRADE: very low). Sarcopenia was associated with worse physical function (GRADE: very low) and lower rate of home discharge (OR: 0.14; 95%CI: 0.09-0.20; I²:30%; GRADE: low). Frailty was associated with increased mortality (GRADE: very low), hospital readmission (GRADE: very low), and decreased home discharge (GRADE: very low).

CONCLUSION

Wasting conditions in older adults during rehabilitation admission may be associated with poorer quality of life, lower rates of home discharge, and higher rates of health service use, physical dysfunction, and mortality following discharge. Further research is needed to investigate the comparative and combined impacts, as well as the overlap of malnutrition, sarcopenia, and frailty during and after rehabilitation to guide priority screening and intervention.

Advanced Oxidation Protein Products Contribute to Chronic-Kidney-Disease-Induced Adipose Inflammation through Macrophage Activation

Fat atrophy and adipose tissue inflammation can cause the pathogenesis of metabolic symptoms in chronic kidney disease (CKD). During CKD, the serum levels of advanced oxidation protein products (AOPPs) are elevated. However, the relationship between fat atrophy/adipose tissue inflammation and AOPPs has remained unknown. The purpose of this study was to investigate the involvement of AOPPs, which are known as uremic toxins, in adipose tissue inflammation and to establish the underlying molecular mechanism. In vitro studies involved co-culturing mouse-derived adipocytes (differentiated 3T3-L1) and macrophages (RAW264.7). In vivo studies were performed using adenine-induced CKD mice and AOPP-overloaded mice. Fat atrophy, macrophage infiltration and increased AOPP activity in adipose tissue were identified in adenine-induced CKD mice. AOPPs induced MCP-1 expression in differentiated 3T3-L1 adipocytes via ROS production. However, AOPP-induced ROS production was suppressed by the presence of NADPH oxidase inhibitors and the scavengers of mitochondria-derived ROS. A co-culturing system showed AOPPs induced macrophage migration to adipocytes. AOPPs also up-regulated TNF-α expression by polarizing macrophages to an M1-type polarity, and then induced macrophage-mediated adipose inflammation. In vitro data was supported by experiments using AOPP-overloaded mice. AOPPs contribute to macrophage-mediated adipose inflammation and constitute a potential new therapeutic target for adipose inflammation associated with CKD.

Association of Body Mass Index and Acute Kidney Injury Incidence and Outcome: A Systematic Review and Meta-Analysis

This study aims to provide pooled estimates for the incidence of acute kidney injury (AKI) in overweight, obese, and normal body mass index (BMI) patients, and to assess impact of BMI on mortality and chronic kidney disease (CKD) rates. We conducted literature search using online databases to analyze outcomes of BMI. This meta-analysis included 22 studies. Compared to normal BMI, underweight, overweight, or obese patients had higher risk of having AKI. Underweight individuals had 17% lower CKD risk (relative risk [RR]: 0.83, 95% confidence interval [CI]: 0.75, 0.90) while patients that were overweight (RR: 1.15, 95% CI: 1.08, 1.22) and obese (RR: 1.21, 95% CI: 1.10, 1.33) had higher risk of having CKD. Lower than normal BMI was associated with higher mortality risk (RR: 1.58, 95% CI: 1.35, 1.85), while being overweight or obese correlated with the decreased risk of mortality. An increased risk of AKI combined with an increased risk of mortality calls for renal protective strategies in subjects who are underweight at the time of hospital admission.

Does Intradialytic Group Exercise Programme Influence Patient-Reported Outcomes, Laboratory Parameters, and Anthropometric Parameters in Maintenance Hemodialysis Patients? A Single-Group Repeated-Measures Trial

BACKGROUND

Maintenance hemodialysis(MHD) patients often suffer from fatigue and are recommended to undertake physical activities. The optimal format of exercise rehabilitation for MHD patients remains uncertain despite demonstrated health benefits. This study aimed to evaluate the effectiveness of an intradialytic group exercise programme for MHD patients.

METHODS

This was a single-centre, single-group repeated-measures design study. The 12-week, three times per-week intradialytic group exercise programme was conducted for around 30 min during the first 2 hours of each dialysis session. Patient-reported outcomes including fatigue, anxiety, depression and health-related quality of life, laboratory parameters including haemoglobin, albumin, pre-albumin and hypersensitive C-reactive protein, and anthropometric parameters including triceps skinfold thickness, mid-upper arm circumference, mid-arm muscle circumference and handgrip strength, were measured at baseline, immediately post-intervention and 12-weeks post-intervention. The repeated-measures analysis of variance and Friedman test were used to compare the parametric and non-parametric data across time points, respectively.

RESULTS

Ninety patients were enrolled and 75 completed. Participants reported significant improvements across time points in fatigue (F = 10.19, p < 0.01), depression (F = 19.20, p < 0.001), health-related quality of life (F = 5.36, p = 0.006), haemoglobin (F = 3.43, p = 0.047), albumin (F = 4.42, p = 0.032), hypersensitive C-reactive protein (χ ² = 50.39, p < 0.001), pre-albumin (χ ² = 11.85, p = 0.003), triceps skinfold thickness (F = 25.03, p < 0.001), mid-upper arm circumference (F = 6.32, p = 0.005), mid-arm muscle circumference (F = 4.89, p = 0.02), and handgrip strength (F = 13.59, p < 0.001). Although the mean anxiety score tended to reduce, the difference across time points was nonsignificant (F = 1.33, p = 0.27).

CONCLUSION

The findings suggested that the intradialytic group exercise programme could improve MHD patients' fatigue, depression, health-related quality of life, nutritional status, and inflammation.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000034394 (04/07/2020).

Handgrip Strength Index: A Novel Parameter Which Quantifies Clinical Weakness in People on Haemodialysis

OBJECTIVE

The muscle strength in people on haemodialysis is associated with nutritional status, quality of life, functional independence, and survival. Handgrip Strength (HGS) is simple to measure, but clinical interpretation is limited by the lack of reference ranges for a haemodialysis population. This study aims to define a novel parameter, HGS index, which quantifies degree of clinical weakness specific to a haemodialysis population and to test if this predicts survival.

METHODS

In a cross-sectional single center study HGS was measured in stable participants on haemodialysis. HGS in the well-nourished subgroup, was used to develop a predictive equation for "expected" HGS according to demographic variables. This then was compared to observed HGS resulting in HGS index (%), an individualized parameter indicating weakness due to clinical variables while accounting for demographic contributors to strength. The association between HGS index and survival was explored in all participants.

RESULTS

Among 427 well-nourished individuals on haemodialysis, HGS was strongly associated with demographic variables and predicted in males by the equation: HGS (kg) = 0.38∗height (cm) - 0.31∗age (years) - 18, and in females by the equation: HGS (kg) = 0.25∗height (cm) - 0.11∗age (years) - 16. Among 547 participants (22% with protein energy wasting), lower HGS index was associated with diabetes (P = .004), lower body mass index (BMI) (P = .005), lower albumin (P = .033), and longer dialysis vintage (P = .007). Over a mean observation period of 2.8 years, quintile of HGS index was strongly associated with survival (P = .023), and in a Cox proportional hazards model, the independent predictors of mortality were age, albumin, BMI and HGS index.

CONCLUSION

HGS index, defined as observed relative to expected HGS, is an individualized measure of clinical weakness. It is a novel parameter which independently predicts survival. HGS index improves the detection of clinically relevant muscle weakness in people on haemodialysis, opening up the possibility of earlier, individualized interventions, and improving outcomes in this vulnerable group.

Associations Between Adult Triceps Skinfold Thickness and All-Cause, Cardiovascular and Cerebrovascular Mortality in NHANES 1999–2010: A Retrospective National Study

Background:

The association between triceps skinfold (TSF) thickness and mortality in previous studies was controversial. This study aimed to explore how TSF thickness affects all-cause, cardiovascular, and cerebrovascular mortality among the United States (U.S.) general population.

Methods

Our research included 25,954 adults in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010. Participants were categorized by the baseline TSF quartiles [quartile 1 (Q1): &lt; 11.8, (Q2): 11.8–17.4, (Q3): 17.4–25, and (Q4): ≥25; unit: millimeter (mm)]. Cox regression models were used to assess the association of TSF with all-cause, cardiovascular, and cerebrovascular mortality. The association between mid-arm muscle circumference (MAMC) and mortality was also explored. Subgroup analyses were conducted to assess heterogeneity in different subgroups.

Results

The highest TSF group (Q4) had the lowest risk to experience all-cause (HR, 0.46; 95% CI, 0.38–0.59; P &lt; 0.001) and cardiovascular mortality (HR, 0.35; 95% CI, 0.23–0.54; P &lt; 0.001) than the lowest TSF group (Q1) after multivariate adjustment. However, there was no relationship between TSF quartiles and cerebrovascular mortality (HR, 0.98; 95%CI, 0.42–2.30; P = 0.97). The protective effects of TSF thickness on mortality still existed after adjusting for BMI and MAMC. For every 1 mm increase in TSF thickness, the risk of all-cause and cardiovascular death decreased by 4% (HR, 0.96; 95% CI, 0.95–0.97; P &lt; 0.001) and 6% (HR, 0.94; 95% CI, 0.93–0.96; P &lt; 0.001), respectively. In the stratified analysis, the relationships between TSF and mortality risk were generally similar across all subgroups.

Conclusions

Higher TSF thickness was associated with lower all-cause and cardiovascular mortality, independent of BMI and MAMC. Our study revealed that the TSF thickness may be a convenient and credible indicator to predict mortality, especially in those with severe cardiovascular diseases.

Predialysis Urea Nitrogen Is a Nutritional Marker of Hemodialysis Patients

End-stage renal disease (ESRD) patients on hemodialysis have poor nutritional status and associated problems such as inflammation and sarcopenia. Blood urea nitrogen (BUN) is an important measure of uremic toxins, and urea reduction is a marker of hemodialysis efficacy. However, a low protein diet for lower BUN could aggravate malnutrition in patients, and optimal pre-dialysis BUN is not defined. We investigated the association of pre-dialysis BUN with patients' comorbidities and the relationship between pre-dialysis BUN and serum albumin as a nutrient marker. Among the 67 patients, the average pre- and post-dialysis BUN were 59.2 and 15.0 mg/dL, respectively, serum creatinine was 10.1 mg/dL, and the average serum albumin was 4.0 g/dL. Patients' age was negatively correlated with serum creatinine (r=-0.277, p<0.05) and albumin (r=-0.453, p<0.001). Predialysis BUN showed a significant positive correlation with serum albumin (r=0.287, p<0.05) and creatinine (r=0.454, p<0.001). However, the predialysis BUN was not significantly related to diabetes, coronary artery disease, congestive heart failure, or cerebrovascular disease. Hemodialysis patients with high pre-dialysis BUN and high serum creatinine could be regarded as having good nutritional status. The significance of this study lies in the potential utility of pre-dialysis blood urea nitrogen as an indicator of the nutritional status of patients. Liberal protein intake might be recommended to adequately dialyzed patients.

A prospective cohort study on the association of lean body mass estimated by mid-upper arm muscle circumference with hypertension risk in Chinese residents

The associations of lean body mass (LBM) with elevated blood pressure (BP) and hypertension were controversial, and the causalities have never been shown. Mid-upper arm muscle circumference (MAMC), an easily obtained anthropometric measurement, could provide an accurate estimate for LBM. Therefore, a prospective cohort study in general Chinese residents aiming to find out the relationship between LBM estimated using MAMC and hypertension risk was performed. Eight thousand one hundred eighty-five eligible participants were included in the baseline analysis, among whom 3442 were subsequently selected into cohort analysis. MAMC was calculated using mid-upper arm circumference (MUAC) and triceps skinfold thickness (TST). Associations of MAMC with BP values and hypertension prevalence were estimated by linear and logistic regression models. Associations with hypertension incidence were estimated by COX regression models, hazard ratio (HR) and 95% confidence interval (CI) were given. Nonlinear relationship between MAMC and hypertension risk was estimated using restricted cubic spline method. Standardized coefficients of MUAC and TST were compared to estimate their strengths of associations with hypertension. Baseline analysis showed that after adjusted for confounders, the increase of systolic BP per standard deviation (SD) of MAMC were 1.97 mmHg (95%CI: 1.46, 2.48) and 1.63 mmHg (95%CI: 1.10, 2.16) respectively in men and women, and the increases of diastolic BP per SD were 1.58 mmHg (95%CI: 1.23, 1.92) and 1.08 mmHg (95%CI: 0.74, 1.42). Additionally, the association of MAMC with the prevalence of hypertension were also found in both men and women (OR = 1.36, 95%CI: 1.26, 1.47 in men; OR = 1.33, 95%CI: 1.22, 1.44 in women). Cohort analysis showed that MAMC increased the risk of hypertension (HR = 1.10, 95%CI: 1.01, 1.19 for men; HR = 1.15, 95%CI: 1.06, 1.26 for women), and a trend of J-shaped relationship was found. Additionally, the stronger associations of MUAC with both BP values and hypertension than that of TST were found in both baseline and cohort analyses. Findings in our study implied that we cannot neglect the capacity of LBM in predicting hypertension risk, and LBM estimates should be recommended in general health surveys or examinations.

Large mid-upper arm circumference is associated with reduced insulin resistance independent of BMI and waist circumference: A cross-sectional study in the Chinese population

BACKGROUND

Body mass index (BMI) is a common indicator in clinical practice, but it is not sufficient to predict insulin resistance (IR). Other anthropometric methods supplement BMI in the assessment of body composition, which can be predicted more accurately. This cross-sectional study aimed to evaluate the association between mid-upper arm circumference (MUAC), triceps skinfold (TSF) thickness, mid-arm muscle circumference (MAMC) and IR in Chinese adults.

METHODS

This cross-sectional study analyzed data from the 2009 China Health and Nutrition Survey database. The study population was divided into four groups according to the MUAC quartiles, and the homeostasis mode assessment was used to evaluate the degree of IR. Logistic regression analysis was performed to calculate odds ratios (ORs) with 95% confidence intervals (CIs), with adjustments for multiple covariates. Subgroup analyses stratified by age, sex, BMI, waist circumference (WC), smoking status, and alcohol consumption were performed.

RESULTS

In total, 8,070 participants were included in the analysis. As MUAC increased, BMI, TSF thickness, MAMC, and the proportion of IR tended to increase. However, we found that there was a significant negative association between MUAC and MAMC and IR in the logistic regression analysis, independent of BMI and WC, the ORs for the highest quartiles compared with the lowest quartiles were 0.662 (95%CI: 0.540-0.811) and 0.723 (95%CI: 0.609-0.860), respectively. There was no significant association was observed between the TSF thickness and IR (OR=1.035 [95%CI: 0.870-1.231]). The inverse associations were more pronounced among participants with lower BMI and WC. No significant age-specific differences were observed (P-heterogeneity > 0.05).

CONCLUSIONS

After adjusting for BMI and WC, MUAC was negatively associated with IR in Chinese adults, and the association between MUAC and IR was derived from arm muscle instead of subcutaneous fat. MUAC could be an additional predictor of IR besides BMI and WC in clinical practice.

Assessment of uremic sarcopenia in dialysis patients: An update

Uremic sarcopenia, which is highly prevalent in dialysis patients, leads to an increased risk of adverse outcomes, such as poor quality of life, falls, fracture, hospitalization, and even mortality. Therefore, early detection of uremic sarcopenia is crucial for administering quick and adequate multidisciplinary therapy to improve clinical outcomes. This review updates the current information about uremic sarcopenia assessment in chronic dialysis patients. We discuss the methods of assessing skeletal muscle mass, strength, and physical performance. We also discuss surrogate markers derived from serum and dialysate creatinine, in addition to emerging screening tools. The prevalence, clinical relevance, and impact of uremic sarcopenia on survival are reviewed and we discuss the limitations and challenges in applying the current working definition of sarcopenia based on the senior population to dialysis patients. The review shows that dialysis patients with skeletal muscle weakness or poor physical performance, either with or without low skeletal muscle mass, should undergo multidisciplinary therapy, included nutritional counseling, lifestyle modification, and exercise intervention, to mitigate the detrimental effects of uremic sarcopenia.

Glycine increases fat-free mass in malnourished haemodialysis patients: a randomized double-blind crossover trial

BACKGROUND

Protein energy wasting is associated with negative outcome in patients under chronic haemodialysis (HD). Branched-chain amino acids (BCAAs) may increase the muscle mass. This post hoc analysis of a controlled double-blind randomized crossover study assessed the impact of BCAAs on nutritional status, physical function, and quality of life.

METHODS

We included 36 chronic HD patient features of protein energy wasting as plasma albumin <38 g/L, and dietary intakes <30 kcal/kg/day and <1 g protein/kg/day. Patients received either oral BCAA (2 × 7 g/day) or glycine (2 × 7 g/day) for 4 months (Period 1), followed by a washout period of 1 month, and then received the opposite supplement (Period 2). The outcomes were lean body mass measured by dual-energy X-ray absorptiometry, fat-free mass index measured by bioelectrical impedance, resting energy expenditure, dietary intake and appetite rating, physical activity and function, quality of life, and blood parameters. Analyses were performed by multiple mixed linear regressions including type of supplementation, months, period, sex, and age as fixed effects and subjects as random intercepts.

RESULTS

Twenty-seven patients (61.2 ± 13.7 years, 41% women) were compliant to the supplementations (consumption >80% of packs) and completed the study. BCAA did not affect lean body mass index and body weight, but significantly decreased fat-free mass index, as compared with glycine (coeff -0.27, 95% confidence interval -0.43 to -0.10, P = 0.002, respectively). BCAA and glycine intake had no effect on the other clinical parameters, blood chemistry tests, or plasma amino acids.

CONCLUSIONS

Branched-chain amino acid did not improve lean body mass as compared with glycine. Unexpectedly, glycine improved fat-free mass index in HD patients, as compared with BCAA. Whether long-term supplementation with glycine improves the clinical outcome remains to be demonstrated.

Sarcopenia diagnosis using different criteria as a predictor of early mortality in patients undergoing hemodialysis

OBJECTIVES

Chronic kidney disease (CKD) is a public health problem, causing secondary sarcopenia. The aim of this study was to evaluate sarcopenia using the definitions proposed by European Working Group on Sarcopenia in Older People in 2010 (EWGSOP₂₀₁₀) and 2019 (EWGSOP₂₀₁₉) as an independent prognostic factor for worse survival in patients with CKD undergoing hemodialysis.

METHODS

Muscle mass, muscle strength, and physical performance were assessed in a cohort of patients with CKD on hemodialysis. The sample consisted of 127 patients (40% >60 y of age) and 36 patients (28.3%) died after a median follow-up length of 23.5 mo (interquartile range= 14.9 - 29). The EWGSOP₂₀₁₀ and EWGSOP₂₀₁₉ definitions were used for diagnosing sarcopenia. Sarcopenia association with mortality by both definitions was investigated using Kaplan-Meier curves and Cox proportional hazard models. The area under the curve, sensitivity, specificity, positive, and negative predictive values for both definitions were also compared.

RESULTS

Patients diagnosed with sarcopenia by both criteria had almost three times higher risk for mortality (95% confidence interval,1.45-6.06 and 1.44-6.13, respectively). Patients classified with severe sarcopenia by both definitions had a significantly lower survival, even after the adjusted analysis. The areas under the curve for EWGSOP₂₀₁₀ and EWGSOP₂₀₁₉ did not significantly differ. The sensitivity/specificity analysis was considered similar for both criteria, and around 70% of the patients was correctly classified.

CONCLUSION

Sarcopenia, notably severe sarcopenia, diagnosed by EWGSOP₂₀₁₀ or EWGSOP₂₀₁₉ criteria, is an independent prognostic factor for worse survival in this population. Early detection with effective interventions may decrease the higher mortality risk among patients with sarcopenia and CKD.

Association of the nutritional risk index for Japanese hemodialysis patients with long-term mortality: The Q-Cohort Study

BACKGROUND

Protein-energy wasting (PEW) is a risk factor for mortality in patients undergoing hemodialysis. Recently, a nutritional risk index for Japanese hemodialysis patients (NRI-JH) has been proposed as a surrogate index of PEW. However, no study has determined the association of the NRI-JH with long-term mortality in patients undergoing hemodialysis. Furthermore, the validity of the NRI-JH has not been confirmed.

METHODS

In total, 3046 patients undergoing hemodialysis and registered in the Q-Cohort Study were followed up for 10 years. The NRI-JH was calculated on the basis of body mass index and serum levels of albumin, total cholesterol, and creatinine. The patients were divided into four groups according to the NRI-JH scores: 0-3 (G1, n = 1343), 4-7 (G2, n = 1136), 8-10 (G3, n = 321), and 11-13 (G4, n = 246). We examined the association between the NRI-JH and the 4-year and 10-year risks of all-cause, cardiovascular, and infection-related deaths using the Cox proportional hazards model.

RESULTS

During the follow-up period, 647 patients died during the first 4 years, and 1503 patients died within 10 years. The 4-year prognosis was analyzed and compared with the lowest NRI-JH score group. Multivariable-adjusted hazard ratios (95% confidence intervals) for all-cause death were 1.93 (1.57-2.38), 2.68 (2.05-3.50), and 3.16 (2.40-4.16) in the G2, G3, and G4 groups, respectively. Similarly, a higher NRI-JH score was associated with an increased risk of cardiovascular and infection-related deaths.

CONCLUSION

A higher NRI-JH score was associated with an increased risk of long-term mortality in patients undergoing maintenance hemodialysis.

TRIAL REGISTRATION

The study protocol was registered in the University Hospital Medical Information Network (UMIN) clinical trial registry (UMIN ID: 000000556).

Mid-Arm Muscle and Subcutaneous Fat Associated with All-Cause Mortality Independent of BMI: A Prospective Cohort Study

OBJECTIVE

This study aimed to systematically evaluate the association between triceps skinfold (TSF) thickness (which indicates subcutaneous fat) mid-arm muscle circumference (MAMC; which reflects muscle mass), mid-upper arm circumference (MUAC), and all-cause mortality.

METHODS

A total of 17,717 adults from the China Health and Nutrition Survey (1993-2015) were included. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality. The joint effect of TSF thickness and MAMC was examined, and planned subgroup analyses were performed.

RESULTS

The highest quartiles of TSF thickness, MAMC, and MUAC were significantly associated with low all-cause mortality, independent of BMI (TSF thickness: HR = 0.704 [95% CI: 0.575-0.862]; MAMC: HR = 0.729 [95% CI: 0.607-0.876]; MUAC: HR = 0.713 [95% CI: 0.583-0.872]). A 1-SD increase showed comparable risk reductions for TSF thickness and MAMC (14.6% and 14.0%), with 16.1% risk reductions in MUAC. There were positive additive interactions between TSF thickness and MAMC. The inverse association existed in young, middle-aged, and elderly participants (P-heterogeneity > 0.05).

CONCLUSIONS

Mid-arm muscle and subcutaneous fat were inversely associated with all-cause mortality, independent of BMI, beyond the elderly population. Mid-arm muscle and subcutaneous fat made comparable contributions to and had positive joint effects on all-cause mortality.

Indoxyl-Sulfate-Induced Redox Imbalance in Chronic Kidney Disease

The accumulation of the uremic toxin indoxyl sulfate (IS) induces target organ damage in chronic kidney disease (CKD) patients, and causes complications including cardiovascular diseases, renal osteodystrophy, muscle wasting, and anemia. IS stimulates reactive oxygen species (ROS) production in CKD, which impairs glomerular filtration by a direct cytotoxic effect on the mesangial cells. IS further reduces antioxidant capacity in renal proximal tubular cells and contributes to tubulointerstitial injury. IS-induced ROS formation triggers the switching of vascular smooth muscular cells to the osteoblastic phenotype, which induces cardiovascular risk. Low-turnover bone disease seen in early CKD relies on the inhibitory effects of IS on osteoblast viability and differentiation, and osteoblastic signaling via the parathyroid hormone. Excessive ROS and inflammatory cytokine releases caused by IS directly inhibit myocyte growth in muscle wasting via myokines’ effects. Moreover, IS triggers eryptosis via ROS-mediated oxidative stress, and elevates hepcidin levels in order to prevent iron flux in circulation in renal anemia. Thus, IS-induced oxidative stress underlies the mechanisms in CKD-related complications. This review summarizes the underlying mechanisms of how IS mediates oxidative stress in the pathogenesis of CKD’s complications. Furthermore, we also discuss the potential role of oral AST-120 in attenuating IS-mediated oxidative stress after gastrointestinal adsorption of the IS precursor indole.

Significance of Adipose Tissue Maintenance in Patients Undergoing Hemodialysis

In the general population, obesity is known to be associated with adverse outcomes, including mortality. In contrast, high body mass index (BMI) may provide a survival advantage for hemodialysis patients, which is known as the obesity paradox. Although BMI is the most commonly used measure for the assessment of obesity, it does not distinguish between fat and lean mass. Fat mass is considered to serve as an energy reserve against a catabolic condition, while the capacity to survive starvation is also thought to be dependent on its amount. Thus, fat mass is used as a nutritional marker. For example, improvement of nutritional status by nutritional intervention or initiation of hemodialysis is associated with an increase in fat mass. Several studies have shown that higher levels of fat mass were associated with better survival in hemodialysis patients. Based on body distribution, fat mass is classified into subcutaneous and visceral fat. Visceral fat is metabolically more active and associated with metabolic abnormalities and inflammation, and it is thus considered to be a risk factor for cardiovascular disease and mortality. On the other hand, subcutaneous fat has not been consistently linked to adverse phenomena and may reflect nutritional status as a type of energy storage. Visceral and subcutaneous adipose tissues have different metabolic and inflammatory characteristics and may have opposing influences on various outcomes, including mortality. Results showing an association between increased subcutaneous fat and better survival, along with other conditions, such as cancer or cirrhosis, in hemodialysis patients have been reported. This evidence suggests that fat mass distribution (i.e., visceral fat and subcutaneous fat) plays a more important role for these beneficial effects in hemodialysis patients.

Hart K, Engel B. A Cross-Sectional Analysis of Dietary Intake and Nutritional Status of Patients on Haemodialysis Maintenance Therapy in a Country of Sub-Saharan Africa

Malnutrition is common among dialysis patients, but there is insufficient literature on the problem from resource-poor settings of the sub-Saharan region. We conducted a cross-sectional investigation of dietary intake and nutritional status of haemodialysis (HD) patients to inform the current status of this population group in the region. HD patients aged ≥18 years, with dialysis vintage of ≥3 months, at one nephrology unit in Tanzania were assessed for their habitual diet and nutrient intake. Anthropometric measures and biochemistry tests were also performed. The diet was predominantly starchy food based, accompanied by a limited selection of vegetables. Fruits and animal protein were also minimally consumed (1 portion/day each). Fruit consumption was higher in females than males (median (25th, 75th) = 2 (1, 2.3) versus 0.5 (0, 1.7) portions, p = 0.008). More than 70% of participants had suboptimal measures for protein and energy intake, dietary iron, serum albumin, muscle mass, and hand grip strength (HGS). Inadequacies in protein and energy intake and dialysis clearance (URR) increased with the increase in body weight/BMI and other specific components (MAMC and FMI). Consumption of red meats correlated significantly and positively with serum creatinine (r = 0.46, p = 0.01), potassium (r = 0.39, p = 0.03), and HGS (r = 0.43, p = 0.02) and was approaching significance for a correlation with serum iron (r = 0.32, p = 0.07). C-RP correlated negatively with albumin concentration (r = -0.32, p = 0.02), and participants with C-RP within acceptable ranges had significantly higher levels of haemoglobin (p = 0.03, effect size = -0.28). URR correlated negatively with haemoglobin concentration (r = -0.36, p = 0.02). Patients will benefit from improved nutritional services that deliver individually tailored and culturally practical dietary advice to enable them to make informed food choices whilst optimizing disease management.

β2-adrenergic receptor agonist counteracts skeletal muscle atrophy and oxidative stress in uremic mice

In patients with chronic kidney disease, skeletal muscle dysfunction is associated with mortality. Uremic sarcopenia is caused by ageing, malnutrition, and chronic inflammation, but the molecular mechanism and potential therapeutics have not been fully elucidated yet. We hypothesize that accumulated uremic toxins might exert a direct deteriorative effect on skeletal muscle and explore the pharmacological treatment in experimental animal and culture cell models. The mice intraperitoneally injected with indoxyl sulfate (IS) after unilateral nephrectomy displayed an elevation of IS concentration in skeletal muscle and a reduction of instantaneous muscle strength, along with the predominant loss of fast-twitch myofibers and intramuscular reactive oxygen species (ROS) generation. The addition of IS in the culture media decreased the size of fully differentiated mouse C2C12 myotubes as well. ROS accumulation and mitochondrial dysfunction were also noted. Next, the effect of the β2-adrenergic receptor (β2-AR) agonist, clenbuterol, was evaluated as a potential treatment for uremic sarcopenia. In mice injected with IS, clenbuterol treatment increased the muscle mass and restored the tissue ROS level but failed to improve muscle weakness. In C2C12 myotubes stimulated with IS, although β2-AR activation also attenuated myotube size reduction and ROS accumulation as did other anti-oxidant reagents, it failed to augment the mitochondrial membrane potential. In conclusion, IS provokes muscular strength loss (uremic dynapenia), ROS generation, and mitochondrial impairment. Although the β2-AR agonist can increase the muscular mass with ROS reduction, development of therapeutic interventions for restoring skeletal muscle function is still awaited.

Comparison of Body Composition Monitor and InBody 720 Bioimpedance Devices for Body Composition Estimation in Hemodialysis Patients and Healthy Controls

Bioelectric impedance devices have become a standard of care not only for peritoneal dialysis but also for hemodialysis patients. We compared the most important body composition variables (extracellular water, intracellular water, total body water and fat mass) measured with the multifrequency bioelectric impedance device InBody 720 (MF-BIA) and bioimpedance spectroscopy body composition monitor Fresenius (BIS BCM) in hemodialysis patients (n = 51, 175.1 + 7.8 cm, 82.2 + 15.2 kg) and healthy controls (n = 51, 175.1 + 7.6 cm, 82.3 + 15.3 kg). The MF-BIA InBody 720 device compared to the BIS BCM device showed significantly larger total body water and intracellular water estimates and significantly smaller extracellular water and body fat estimates in hemodialysis patients (p < 0.001). These differences (p < 0.001) were similar in the cohort of healthy controls; moreover, we observed high correlations in all variables between the hemodialysis patients and the healthy controls (0.80–0.95, p < 0.001). The mean relative differences in the order of 8% were lower for extracellular water and total body fat, but the limits of agreement were still wide enough to be clinically significant. We conclude that the results of the measurements with InBody 720 and BCM Fresenius cannot be used interchangeably. Physicians and nutritionists involved in the care of hemodialysis patients should be aware of this discrepancy between the two devices and should try to use the same device to track the body in their hemodialysis population in a longitudinal direction.

Circulating fatty acid profiles are associated with protein energy wasting in maintenance hemodialysis patients: a cross-sectional study

The metabolic impact of circulating fatty acids (FAs) in patients requiring hemodialysis (HD) is unknown. We investigated the associations between plasma triglyceride (TG) FAs and markers of inflammation, insulin resistance, nutritional status and body composition. Plasma TG-FAs were measured using gas chromatography in 341 patients on HD (age = 55.2 ± 14.0 years and 54.3% males). Cross-sectional associations of TG-FAs with 13 markers were examined using multivariate linear regression adjusted for potential confounders. Higher levels of TG saturated fatty acids were associated with greater body mass index (BMI, r = 0.230), waist circumference (r = 0.203), triceps skinfold (r = 0.197), fat tissue index (r = 0.150), serum insulin (r = 0.280), and homeostatic model assessment of insulin resistance (r = 0.276), but lower malnutrition inflammation score (MIS, r =  − 0.160). Greater TG monounsaturated fatty acid levels were associated with lower lean tissue index (r =  − 0.197) and serum albumin (r =  − 0.188), but higher MIS (r = 0.176). Higher levels of TG n-3 polyunsaturated fatty acids (PUFAs) were associated with lower MIS (r =  − 0.168) and interleukin-6 concentrations (r =  − 0.115). Higher levels of TG n-6 PUFAs were associated with lower BMI (r =  − 0.149) but greater serum albumin (r = 0.112). In conclusion, TG monounsaturated fatty acids were associated with poor nutritional status, while TG n-3 PUFAs were associated with good nutritional status. On the other hand, TG saturated fatty acids and TG n-6 PUFAs had both favorable and unfavorable associations with nutritional parameters.

Modified Creatinine Index and Clinical Outcomes of Hemodialysis Patients: An Indicator of Sarcopenia?

OBJECTIVE

Sarcopenia (especially muscle mass assessed using gold standard techniques) has been suggested as a poorer predictor of mortality than muscle function in patients undergoing hemodialysis. Appropriate methods to estimate muscle mass for use as a good predictor of clinical outcomes remain to be established. We investigated whether the modified creatinine index (mCI), which is a surrogate marker of muscle mass, could predict mortality and cardiovascular (CV) hospitalizations independent of muscle function and other confounders in patients on hemodialysis.

DESIGN AND METHODS

In this retrospective study, outpatients (n = 542; mean age, 65.3 years; 60% men; median dialysis vintage, 29 months; mean BMI, 22.0 kg/m²) undergoing hemodialysis were investigated. The mCI, handgrip strength, and gait speed were assessed and related to all-cause mortality and a composite of CV hospitalizations and all-cause mortality. Cox proportional and mixed-effects negative binomial models were fit for mortality and the composite outcomes.

RESULTS

Patients were followed up for a median 3 years (interquartile range: 1.5-5.7). Each per SD increase of mCI (HR:0.63, 95% CI:0.62-0.65), handgrip strength (HR:0.51, 95% CI:0.48-0.54), and gait speed (HR:0.60, 95% CI:0.56-0.64) were significantly associated with lower all-cause mortality rates after adjusting for covariates. The mCI was consistently found to be an independent predictor of mortality after additional adjustment for handgrip strength or gait speed. Furthermore, sarcopenic conditions [i.e., lower mCI, and lower handgrip strength (HR:3.79, 95% CI:2.09-6.87) or slower gait speed (HR:4.20, 95% CI:2.38-7.41)] were significantly associated with a higher risk of mortality after adjusting for covariates. Associations of mCI with multiple CV hospitalizations and mortality were similar to those between mCI and mortality.

CONCLUSION

The mCI was a good predictor of clinical outcomes and was comparable to muscle function, including handgrip strength and gait speed. The mCI is likely to provide additional diagnostic and prognostic values for sarcopenia in patients on hemodialysis.

Low relative skeletal muscle mass predicts incident hypertension in Korean men: a prospective cohort study

OBJECTIVE

Previous cross-sectional studies suggest an association between low muscle mass and hypertension. However, whether low muscle mass predicts the development of hypertension is unknown. The aim of this study is to investigate the relationship between relative muscle mass and incident hypertension in a large prospective cohort of Korean adults.

METHODS

In this prospective cohort study, we analyzed 132 324 participants without hypertension at baseline who underwent two health check-ups in 2012 and 2016 or in 2013 and 2017 with a 4-year interval. The participants were divided according to skeletal muscle mass index quartiles (Q1--Q4) according to their baseline skeletal muscle mass index [skeletal muscle mass index (%) = total skeletal muscle mass (kg)/body weight (kg) × 100). Multivariate logistic regression was used to estimate the odds ratio and 95% confidence interval for the development of hypertension after 4 years.

RESULTS

After 4 years, 7180 (5.43%) participants developed hypertension. The incidence rates of hypertension were 12.11, 8.58, 6.93, and 4.37% in men and 4.02, 2.29, 1.73, and 1.18% in women in Q1, Q2, Q3, and Q4, respectively. The multivariate adjusted odds ratios (95% confidence intervals) for incident hypertension in Q1, Q2, and Q3, in comparison with Q4, were 1.46 (1.3-1.63), 1.31 (1.19-1.46), and 1.26 (1.14-1.40) in men and 0.97 (0.76-1.23), 1.12 (0.90-1.38), and 1.14 (0.92-1.42) in women, respectively.

CONCLUSION

Low relative skeletal muscle mass was independently and significantly associated with the incidence of hypertension only in Korean men. Further research is required to understand the underlying mechanisms of this relationship.

Uremic Sarcopenia: Clinical Evidence and Basic Experimental Approach

Sustained physical activity extends healthy life years while a lower activity due to sarcopenia can reduce them. Sarcopenia is defined as a decrease in skeletal muscle mass and strength due not only to aging, but also from a variety of debilitating chronic illnesses such as cancer and heart failure. Patients with chronic kidney disease (CKD), who tend to be cachexic and in frail health, may develop uremic sarcopenia or uremic myopathy due to an imbalance between muscle protein synthesis and catabolism. Here, we review clinical evidence indicating reduced physical activity as renal function deteriorates and explore evidence-supported therapeutic options focusing on nutrition and physical training. In addition, although sarcopenia is a clinical concept and difficult to recapitulate in basic research, several in vivo approaches have been attempted, such as rodent subtotal nephrectomy representing both renal dysfunction and muscle weakness. This review highlights molecular mechanisms and promising interventions for uremic sarcopenia that were revealed through basic research. Extensive study is still needed to cast light on the many aspects of locomotive organ impairments in CKD and explore the ways that diet and exercise therapies can improve both outcomes and quality of life at every level.

Effect of high bicarbonate hemodialysis solution on biochemical parameters and anthropometric indices

INTRODUCTION

Protein energy wasting is an adverse consequence of renal failure, which is correlated with increased mortality and morbidity. Metabolic acidosis has a major role in the development of protein energy wasting in hemodialysis patients. Every effort that could ameliorate this catabolic state would be beneficial to stabilize body composition. The aim of this study was to investigate the possible beneficial effects of high bicarbonate dialysis on anthropometric indices and biochemical parameters of nutrition.

METHODS

Fifty-six hemodialysis patients were randomly enrolled in two groups: an intervention group that underwent hemodialysis for 6 months with high bicarbonate dialysate concentration (36 mmol/L, N = 26) and a control group that underwent hemodialysis using a bicarbonate dialysate concentration of 30 mmol/L (N = 30). Biochemical parameters of nutrition and weight, body mass index (BMI), total body water, percent body fat, and other anthropometric indices were measured at the beginning and the end of the trial.

FINDINGS

At the end of the 6 month evaluation period, plasma levels of albumin, phosphorus, K, calcium, and bicarbonate showed no significant changes. Body weight and BMI increased significantly in high bicarbonate arm but did not change significantly in the control group. Percent body fat in the arms and legs did not change in intervention arm, but decreased significantly in the controls.

DISCUSSION

The results suggest that higher bicarbonate dialysis can have beneficial effects on nutritional status and might protect against loss of fat mass.

Correlation between body composition measurement by bioelectrical impedance analysis and intradialytic hypotension

OBJECTIVE

To explore the correlation between body composition measurement by bioelectrical impedance analysis (BIA) and intradialytic hypotension (IDH).

METHODS

The clinical data of 127 patients with end-stage renal disease (ESRD) who underwent regular dialysis in the Blood Purification Center of the Second Affiliated Hospital of Chongqing Medical University were retrospectively analyzed. According to the occurrence of IDH, the patients were divided into IDH group and intradialytic normotension group. The difference in body composition measured by BIA and its relationship with IDH were compared between the two groups.

RESULTS

Compared with intradialytic normotension group, the intracellular water (ICW) ratio (P = 0.009), extracellular water (ECW) ratio (P = 0.029), total body water (TBW) ratio (P = 0.012), protein ratio (P = 0.010), soft lean mass (SLM) ratio (P = 0.011), fat-free mass (FFM) ratio (P = 0.012) and skeletal muscle mass (SMM) ratio (P = 0.009) in IDH group were significantly decreased. However, the fat mass (FM) ratio (P = 0.016), percentage body fat (PBF) ratio (P = 0.001), extracellular water/total body water (ECW/TBW) ratio (P = 0.036), extracellular water/total body water in trunk (ECW/TBWT) ratio (P = 0.045) and visceral fat area (VFA) (P = 0.003) in IDH group were significantly increased when compared with intradialytic normotension group. In addition, there was a positive correlation between systolic blood pressure (SBP) during IDH and ECW ratio, ECW/TBW ratio, and ECW/TBWTR ratio before dialysis.

CONCLUSIONS

The body composition of dialysis patients is closely related to the occurrence of IDH. Strengthening the body composition management of dialysis patients outside the hospital may reduce the occurrence of IDH and improve the long-term prognosis of dialysis patients.

Low body cell mass index in hemodialysis patients: Association with clinical parameters and survival

INTRODUCTION

Body cell mass (BCM) is a useful nutritional marker and is not affected by changes in the hydration status that commonly occur in hemodialysis (HD) patients. This study aimed to examine the association between body cell mass index (BCMI) and nutritional parameters, as well as its relationship with long-term survival in these patients.

METHODS

This longitudinal prospective multicenter study followed a cohort of patients in HD for 24 months. The clinical parameters of 2527 patients (mean age 70.3 ± 14.6 years, 55.8% male and mean HD vintage 58 (IQR:33-95) months) were measured and their body composition parameters were assessed by a body composition monitor before the HD session. BCM was converted to BCMI (BCM/height² ) and, taking into account the mean value (6.4 ± 2.1 kg/m² ), we split our study population into 2 groups: G1 (BCMI <6.4 kg/m² ; n = 1366) and G2 (BCMI ≥ 6.4 kg/m² ; n = 1161). All statistical tests were performed using SPSS 20.0 software. A P value lower than 0.05 was considered statistically significant.

FINDINGS

Patients with a BCMI <6.4 kg/m² displayed higher age (P < 0.001), dialysis adequacy (Kt/V) (P < 0.001), total cholesterol (TC) (P = 0.033), high-density lipoprotein cholesterol (HDL-C) (P < 0.001), relative overhydration (overhydration/extracellular water [OH/ECW]) (P < 0.001), CRP (P < 0.001), fat tissue index (FTI) (P < 0.001) and lower normalized protein equivalent of nitrogen appearance (nPNA) (P < 0.001), albumin (P < 0.001), serum creatinine (P < 0.001), creatinine index (P < 0.001), potassium (P < 0.001), phosphorus (P < 0.001), calcium/phosphorus product (Ca X P) (P < 0.001), lean tissue index (LTI) (P < 0.001) and body mass index (BMI) (P = 0.046). The Kaplan-Meier survival curve showed a significantly better survival in female and male patients with BCMI ≥6.4 kg/m² (P = 0.001 and P < 0.001, respectively). In the cox regression analysis, a significantly higher mortality risk was observed in G1 patients (P = 0.001).

DISCUSSION

Our study showed that a low BCMI was a mortality predictor and was associated with worse nutritional parameters in patients undergoing HD.

Modified creatinine index and risk for long-term infection-related mortality in hemodialysis patients: ten-year outcomes of the Q-Cohort Study

Modified creatinine (Cr) index, calculated by age, sex, pre-dialysis serum Cr concentration, and Kt/V for urea, is an indicator of skeletal muscle mass in hemodialysis (HD) patients. It remains unknown whether the modified Cr index predicts infection-related mortality in this population. We investigated the association between the modified Cr index and infection-related mortality. A total of 3046 patients registered in the Q-Cohort Study, a multicenter, observational study of HD patients, were analyzed. Associations between sex-specific quartiles (Q1–Q4) of the modified Cr index and the risk for infection-related mortality were analyzed by Cox proportional hazard model. During a median follow-up of 8.8 years, 387 patients died of infection. The estimated risk for infection-related mortality was significantly higher in the lower quartiles (Q1, Q2, and Q3) than in the highest quartile (Q4) as the reference group (hazard ratios and 95% confidence intervals [CI]: Q1, 2.89 [1.70–5.06], Q2, 2.76 [1.72–4.62], and Q3, 1.79 [1.12–2.99]). The hazard ratio (95% CI) for a 1 mg/kg/day decrease in the modified Cr index was 1.18 (1.09–1.27, P < 0.01) for infection-related mortality. In conclusion, a lower modified Cr index is associated with an increased risk for long-term infection-related mortality in the HD population.

A Systematic Review of the Acute Effects of Hemodialysis on Skeletal Muscle Perfusion, Metabolism, and Function

Introduction

The underlying mechanisms of skeletal muscle wasting in hemodialysis patients are complex. We performed a systematic review to summarize evidence on whether hemodialysis has acute effects on skeletal muscle perfusion, metabolism, and function.

Methods

The protocol was registered on PROSPERO (Registration number CRD42018103682). A systematic search was performed in MEDLINE, PubMed, Cochrane, Embase, Scopus, and Web of Science. Citation, reference list, and gray literature searches were also performed. Studies were selected in 2 stages: title and abstract review, then full-text review.

Results

A total of 65 full-text articles were reviewed, and 14 studies were eligible for inclusion. No studies were identified that assessed muscle perfusion during dialysis. Two studies used near-infrared spectroscopy to indirectly measure skeletal muscle oxygen consumption, which increased during dialysis in 1 study but only in patients with diabetes in the second. Metabolism was examined in 9 studies. A number of acute metabolic changes were reported (e.g., caspase-3 activity, polyubiquitin, and interleukin-6 protein increased in response to hemodialysis) as was a net negative protein balance over the dialysis session. Three studies examining muscle function did not produce consistent findings.

Conclusion

Gaps remain in understanding the acute effects of hemodialysis on skeletal muscle, particularly for changes in perfusion and function, although there does appear to be an acute effect on muscle metabolism.

Signal regulatory protein alpha initiates cachexia through muscle to adipose tissue crosstalk

BACKGROUND

Muscle wasting from chronic kidney disease (CKD) or from defective insulin signalling results in morbidity and, ultimately, mortality. We have identified an endogenous mediator of insulin resistance, signal regulatory protein alpha (SIRPα), which leads to cachexia in mice and is associated with cachexia in patients with CKD.

METHODS

We assessed insulin signalling and mechanisms causing muscle atrophy plus white adipose tissue (WAT) metabolism in mouse models of CKD or acute diabetes (streptozotocin treatment). We then examined these factors in mice with global knockout (KO) of SIRPα and sought mediators of metabolic responses in muscle and adipose tissues of mice with either muscle-specific or adipose tissue-specific KO of SIRPα. Metabolic responses were confirmed in primary cultures of adipose cells.

RESULTS

In mice with CKD, SIRPα expression was increased in WAT (three-fold, P < 0.05), and this was associated with precursors of cachexia: 'pathologic browning', thermogenesis, and a two-fold activation of protein kinase A (P < 0.05 vs. control mice) plus loss of adipose tissue mass. In contrast, mice with SIRPα global KO and CKD or acute diabetes experienced improved insulin signalling and activation of pAkt plus 'physiologic browning' of WAT. These mice avoided losses of muscle and adipose tissues and experienced a 31% improvement in survival (P < 0.05) than did wild-type mice with CKD. In muscle-specific SIRPα KO mice with CKD, we uncovered that serum SIRPα levels (P < 0.05) were suppressed and were associated with improved insulin signalling both in skeletal muscles and in WAT. These changes were accompanied by physiologic WAT browning. However, in adipose-specific SIRPα KO mice with CKD, levels of serum SIRPα were increased over two-fold (P < 0.05), while muscle losses were minimally inhibited. Clinical implications of SIRPα signalling are suggested by our findings that include increased SIRPα expression in muscle and adipose tissues (P < 0.05 vs. healthy controls) plus higher SIRPα levels in the serum of patients with CKD (2.4-fold, P=0.000017 vs. healthy controls).

CONCLUSIONS

Our results show that SIRPα plays an important role as an anti-insulin mediator regulating pathways to cachexia. In muscle-specific SIRPα KO, changes in SIRPα serum levels seem to improve insulin signalling in muscle and WAT, suggesting crosstalk between muscle and adipose tissue. Therefore, targeting SIRPα may prevent cachexia in patients with CKD or acute diabetes.

Impact of sarcopenia and its diagnostic criteria on hospitalization and mortality in chronic hemodialysis patients: A 3-year longitudinal study

BACKGROUND/PURPOSE

Sarcopenia is prevalent in chronic hemodialysis patients. This prospective cohort study evaluated the impact of sarcopenia and its diagnostic criteria on hospitalization and mortality in 126 chronic hemodialysis patients.

METHODS

Skeletal muscle mass, handgrip strength (HGS), gait speed, and blood parameters were assessed. Sarcopenia was evaluated using the criteria of the European Working Group on Sarcopenia in Older People and the Taiwanese criteria for Sarcopenia. Muscle quality was defined as HGS divided by mid-arm muscle circumference.

RESULTS

Prevalences of uremic sarcopenia were 8.7% and 13.5% according to Taiwanese and European criteria, respectively. Low HGS and gait speed were much more prevalent than low muscle mass. Within 3 years, 79 (62.7%) patients were hospitalized and 26 (20.6%) died. Low HGS and slow gait speed were associated with hospitalization and mortality, while sarcopenia was associated with mortality but not with hospitalization. Notably, in our patients without sarcopenia, close associations between increased hospitalization and mortality risk with low HGS and slow gait speed remained unchanged. In Cox proportional hazard analysis, muscle quality [hazard ratio (HR) = 0.42, 95% confidence interval (CI) = 0.19-0.93, p = 0.032] and serum creatinine (HR = 0.82, 95% CI = 0.71-0.95, p = 0.009) were independently associated with composite outcome of hospitalization or death.

CONCLUSION

Muscle functionality and quality can predict hospitalization and overall survival in chronic hemodialysis patients, better than muscle mass.

Trajectory of Lean Body Mass Assessed Using the Modified Creatinine Index and Mortality in Hemodialysis Patients

RATIONALE & OBJECTIVE

Although a declining body mass index (BMI) is associated with higher mortality in patients on hemodialysis, BMI cannot distinguish lean body mass from fat mass. It remains unclear whether changes over time in lean body mass are associated with mortality. We examined the prognostic significance of changes in the modified creatinine index, a proxy for lean body mass.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Outpatients (n=349; mean age, 67.4 years; 60% men) undergoing maintenance hemodialysis 3 times a week at a treatment center.

PREDICTOR

Modified creatinine index and BMI trajectories over a 1-year period.

OUTCOMES

All-cause mortality.

ANALYTICAL APPROACH

We calculated the percentage of change in modified creatinine index and BMI over a 1-year period. Patients were categorized according to change in modified creatinine index/BMI: no decline (≥0%) or decline (<0%). Kaplan-Meier and Cox proportional hazard analyses were performed to examine whether modified creatinine index and BMI trajectories were associated with mortality.

RESULTS

During follow-up (median, 1,157 days), 79 patients died. Decreasing modified creatinine index (HR, 1.31; 95% CI, 1.11-1.54) and BMI (HR, 1.25; 95% CI, 1.01-1.54) over time, measured as continuous variables and expressed per 1-standard deviation decrease, were independently associated with higher risk for all-cause mortality. The decline in modified creatinine index/no decline in BMI group (HR, 2.14; 95% CI, 1.04-4.45) and the decline in modified creatinine index/decline in BMI group (HR, 3.05; 95% CI, 1.58-5.90) had higher rates of mortality compared to the no decline in modified creatinine index/decline in BMI group.

LIMITATIONS

The absence of a direct measure of lean body and fat mass and limited generalizability to non-Japanese hemodialysis populations.

CONCLUSIONS

The modified creatinine index trajectory is independently associated with mortality and provides additional prognostic information to the BMI trajectory in patients on hemodialysis.

Obesity and synergistic risk factors for chronic kidney disease in African American adults: the Jackson Heart Study

Background

African Americans are at high risk for chronic kidney disease (CKD). Obesity may increase the risk for CKD by exacerbating features of the metabolic syndrome and promoting glomerular hyperfiltration. Whether other factors also affecting these pathways may amplify or mitigate obesity-CKD associations has not been investigated.

Methods

We studied interactions between obesity and these candidate factors in 2043 African Americans without baseline kidney disease enrolled in the Jackson Heart Study. We quantified obesity as body mass index (BMI), sex-normalized waist circumference and visceral adipose volume measured by abdominal computed tomography at an interim study visit. Interactions were hypothesized with (i) metabolic risk factors (dietary quality and physical activity, both quantified by concordance with American Heart Association guidelines) and (ii) factors exacerbating or mitigating hyperfiltration (dietary protein intake, APOL1 risk status and use of renin-angiotensin system blocking medications). Using multivariable regression, we evaluated associations between obesity measures and incident CKD over the follow-up period, as well as interactions with metabolic and hyperfiltration factors.

Results

Assessed after a median of 8 years (range 6-11 years), baseline BMI and waist circumference were not associated with incident CKD. Higher visceral adipose volume was independently associated with incident CKD (P = 0.008) in a nonlinear fashion, but this effect was limited to those with lower dietary quality (P = 0.001; P-interaction = 0.04). In additional interaction models, higher waist circumference was associated with greater risk of incident CKD among those with the low-risk APOL1 genotype (P = 0.04) but not those with a high-risk genotype (P-interaction = 0.02). Other proposed factors did not modify obesity-CKD associations. Conclusions. Higher risks associated with metabolically active visceral adipose volume and interactions with dietary quality suggest that metabolic factors may be key determinants of obesity-associated CKD risk. Interactions between obesity and APOL1 genotype should be considered in studies of African Americans.

Investigating Physical and Nutritional Changes During Prolonged Intermittent Fasting in Hemodialysis Patients: A Prospective Cohort Study

OBJECTIVE

Studies investigating the health effects of prolonged intermittent fasting during Ramadan among Muslim patients on hemodialysis (HD) are limited and reported heterogeneous findings. This study aimed to evaluate the effects of intermittent fasting during Ramadan on nutritional and functional status of patients on maintenance HD.

DESIGN AND METHODS

This was a 12-week, multicenter, prospective observational study. The study setting included three HD centers. Adult Muslim patients, who were undergoing HD session thrice weekly and planned to fast during Ramadan, were screened for eligibility and recruited. Nutritional and functional status assessments were carried out 2 weeks before (V₀), at the fourth week of Ramadan (V₁), and 4 weeks after Ramadan (V₂). Nutritional status parameters included anthropometry (body mass index, interdialytic weight gain, waist circumference), body composition (mid-arm circumference, triceps skinfold, body fat percentage), blood biochemistry (albumin, renal profile, lipid profile, and inflammatory markers), blood pressure, dietary intake, and handgrip strength. Changes in nutritional and functional status parameters across study timepoints were analyzed using repeated-measures analysis of variance.

RESULTS

A total of 87 patients completed the study, with 68 patients (78.2%) reporting fasting ≥20 days. Ramadan fasting led to significant reductions (all P < .05) in body mass index, interdialytic weight gain, waist circumference, mid-arm circumference, fat tissue mass, and body fat percentage, but these were not accompanied by any significant change in lean tissue mass (P > .05). Significant improvement was observed in serum phosphate levels, but serum albumin, urea, and creatinine were also reduced significantly during Ramadan (P < .05). There were no significant changes in lipid profile and inflammatory markers. Interestingly, energy and protein intakes remain unchanged during Ramadan. Handgrip strength improved significantly during Ramadan and further improved after Ramadan.

CONCLUSION

Intermittent Ramadan fasting leads to temporary changes in nutritional status parameters and poses nondetrimental nutritional risk for patients on maintenance HD.

Oral ghrelin receptor agonist MK-0677 increases serum insulin-like growth factor 1 in hemodialysis patients: a randomized blinded study

Background

Protein-energy wasting (PEW) in end-stage renal disease (ESRD) patients is associated with increased morbidity and mortality, but options for treatment are limited. Growth hormone (GH) increases insulin-like growth factor 1 (IGF-1), with improved nutritional parameters, but must be given subcutaneously and does not provide normal GH secretion patterns. MK-0677, an oral ghrelin receptor agonist (GRA), maintains normal GH secretion and increases lean body mass in normal subjects; it has not been studied in dialysis patients, an essential step in assessing efficacy and safety prior to clinical trials.

Methods

We performed a randomized crossover double-blind study in assessing the effect of MK-0677 versus placebo on IGF-1 levels, the primary outcome, in hemodialysis patients. In total, 26 subjects enrolled and 22 completed the 3-month crossover study.

Results

The geometric mean IGF-1 was 1.07-fold greater [95% confidence interval (CI) 0.89-1.27; P = 0.718] after placebo. In patients receiving MK-0677, the geometric mean IGF-1 were 1.76-fold greater (95% CI 1.48-2.10; P < 0.001) following MK-0677. When the data were adjusted for preintervention IGF-1 concentration, the ratio of geometric means (MK-0677 relative to placebo) for the pre- versus postintervention change in the IGF-1 was 1.65 (95% CI 1.33-2.04; P < 0.001). These data demonstrate a 65% greater increase (95% CI 33-104%) in IGF-1 in MK-0677-dosed subjects compared with placebo. There were no serious adverse effects attributable to MK-0677.

Conclusions

MK-0677 increased serum IGF-1 levels with minimal adverse effects in hemodialysis subjects. Studies are needed to evaluate whether long-term therapy with MK-0677 improves PEW, lean body mass, physical strength, quality of life and survival in CKD/ESRD patients.