Protein-energy wasting and mortality in chronic kidney disease

A Comparative Analysis of the SARC-F Questionnaire and the Malnutrition-Inflammation Score for Sarcopenia Risk Assessment and Negative Outcome Probability in Chronic Hemodialysis Patients

Background/Objectives: Protein-energy wasting (PEW) and sarcopenia are common in chronic hemodialysis (HD) patients, leading to numerous complications and increased mortality. This study aimed to compare the reliability of the SARC-F (Strength, Assistance in walking, Rise from a chair, Climb stairs, and Falls) and the Malnutrition-Inflammation Score (MIS) in assessing sarcopenia and predicting negative outcomes in HD patients. Methods: This cross-sectional study enrolled 109 HD patients. Nutritional assessments were performed, and blood samples were taken for routine blood laboratory investigations. The MIS was used as a scoring system to represent the severity of PEW, while the SARC-F was applied as an indicator of sarcopenia risk and general functional capacity. A multivariable logistic regression was conducted to analyze the association of several predictors with a negative cross-sectional outcome (death). Results: Patients with SARC-F scores ≥ 4 and MISs ≥ 6 were older, had significantly lower albumin and prealbumin levels, and more severe anemia. They were also more likely to report weight loss and poor appetite. A higher MIS was closely associated with unfavourable nutritional status according to the International Society of Renal Nutrition and Metabolism (ISRNM) criteria for PEW. However, in 71.25% of patients with satisfactory functional capacity (SARC-F scores 0-3), some form of PEW was still observed. After performing logistic regression modelling, only the MIS remained strongly associated with the probability of a negative outcome. Conclusions: The SARC-F alone often did not correspond to an increased sarcopenia risk or clear clinical and biochemical indicators of PEW in HD patients. When assessing nutritional risk in this group, it is recommended to use more detailed tools, such as the MIS, to ensure the accurate identification of those at the highest risk for negative outcomes.

Inspiratory Muscle Training in Patients Living With Chronic Kidney Disease and Receiving Hemodialysis: Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

People living with chronic kidney disease (CKD) and receiving hemodialysis (HD) have impaired respiratory muscle strength and endurance. The objective of this study was to systematically review the effects of inspiratory muscle training (IMT) on respiratory muscle strength, functional capacity, lung function, quality of life, endothelial function, and oxidative stress in people living with CKD and receiving HD.

METHODS

An electronic search was conducted from inception to June 2023. Randomized controlled trials that evaluated the effects of IMT on respiratory muscle strength, functional capacity, lung function, endothelial function, quality of life, or oxidative stress in adults living with CKD and receiving HD, compared with control, placebo IMT, or conventional physical therapy, were included.

RESULTS

Eight studies were included, totaling 246 people. The meta-analysis showed that IMT increased the maximum inspiratory pressure (MIP) by 22.53 cm H2O, the maximum expiratory pressure (MEP) by 19.54 cm H2O, and the distance covered in the 6-minute walk test by 77.63 m. Changes in lung function and quality of life were not observed. It was not possible to quantitatively analyze data on endothelial function and oxidative stress.

CONCLUSION

IMT improves MIP, MEP, and functional capacity in people living with CKD and receiving HD. IMT did not demonstrate significant results for lung function and quality of life. Effects on endothelial function and oxidative capacity remain uncertain.

IMPACT

Inspiratory muscle training improves MIP, MEP, and functional capacity in people living with CKD and receiving HD, compared with conventional physical therapy or controls or placebo intervention. Increases in functional capacity in this population are extremely important because of the relationship with the survival of these people.

Association of Handgrip Strength and Nutritional Status in Non-Dialysis-Dependent Chronic Kidney Disease Patients: Results from the KNOW-CKD Study

Handgrip strength (HGS) is suggested as an indirect assessment of nutritional status in chronic kidney disease (CKD) patients, but evidence is limited for non-dialysis-dependent CKD (NDD-CKD) patients. This cross-sectional study included 404 patients from the Phase II KoreaN Cohort Study for Outcome in Patients With CKD. HGS, measured twice in each hand, was the exposure, and malnutrition status was defined by a malnutrition-inflammation score (MIS) of 6 or higher. A logistic regression analysis adjusted for age, sex, diabetes mellitus (DM), hypertension, CKD stages, smoking, overhydration, education, and income status was used to assess malnutrition risk. The predictability of HGS for malnutrition was evaluated using the area under the curve (AUC). Patients with lower HGS were older, had a higher prevalence of DM, and lower estimated glomerular filtration rate. Higher HGS was significantly associated with lower malnutrition risk after adjustment (per 1 standard deviation increase, adjusted odds ratio, 0.47 [0.30-0.75]). Subgroup analyses showed no significant interaction between HGS and malnutrition risk across age, sex, DM, and CKD stage. HGS showed fair predictability for malnutrition in men (AUC 0.64 [0.46-0.83]) and women (AUC 0.71 [0.55-0.86]). In conclusion, HGS is a useful diagnostic indicator of malnutrition in NDD-CKD patients.

Association between periodontitis and its treatment on mortality rates of end-stage renal disease: A systematic review and meta-analysis

BACKGROUND

The association between periodontitis and systemic diseases is widely researched. Conflicting literature exists on the relationship between periodontitis and the outcomes of end-stage renal disease (ESRD) patients. We hereby reviewed evidence to examine if periodontitis and its management impact the mortality rates of ESRD patients.

MATERIAL AND METHODS

Literature was searched on the databases of PubMed, Embase, CENTRAL, Web of Science, and Scopus till 27th April 2023. All cohort studies reporting adjusted effect size of the relationship between periodontitis or its management and mortality rates of ESRD patients were included.

RESULTS

Eight studies were eligible of which six reported the association between periodontitis and mortality while two reported between periodontal treatment and mortality. Pooled analysis showed no association between the presence of periodontitis and all-cause mortality amongst ESRD patients (HR: 1.13 95% CI: 0.77, 1.65 I2=72%). Results were unchanged on sensitivity analysis. Pooled analysis of three studies showed no difference in the risk of cardiovascular mortality amongst ESRD patients with and without periodontitis (HR: 1.44 95% CI: 0.57, 3.60 I2=86%). A descriptive analysis of two studies showed that periodontal treatment could reduce the risk of mortality in ESRD patients with periodontitis.

CONCLUSIONS

Limited evidence indicates that periodontitis does not impact all-cause and cardiovascular mortality in ESRD patients. Data on the role of periodontal therapy in improving outcomes is scarce. Further research is needed to generate high-quality evidence on this subject.

Narrative Review: Clinical Implications and Assessment of Frailty in Patients With Advanced CKD

Frailty is a multidimensional clinical syndrome characterized by low physical activity, reduced strength, accumulation of multiorgan deficits, decreased physiological reserve, and vulnerability to stressors. Frailty has key social, psychological, and cognitive implications. Frailty is accelerated by uremia, leading to a high prevalence of frailty in patients with advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD) as well as contributing to adverse outcomes in this patient population. Frailty assessment is not routine in patients with CKD; however, a number of validated clinical assessment tools can assist in prognostication. Frailty assessment in nephrology populations supports shared decision-making and advanced communication and should inform key medical transitions. Frailty screening and interventions in CKD or ESKD are a developing research priority with a rapidly expanding literature base.

Development and validation of a model for predicting the risk of cardiovascular events in maintenance hemodialysis patients

The mortality rates for patients undergoing hemodialysis (HD) remain unacceptably high compared to the general population, and more specific information about the causes of death is not known. The study aimed to develop and validate a risk prediction model that uses common clinical factors to predict the probability of cardiovascular events in maintenance hemodialysis (MHD) patients. The study involved 3488 adult patients who received regular scheduled hemodialysis treatment at 20 hemodialysis centers in southwest China between June 2015 and August 2020, with follow-up until August 2021. The optimal parameter set was identified by multivariable Cox regression analyses and Cross-LASSO regression analyses and was used to establish a nomogram for predicting the risk of cardiovascular events in maintenance hemodialysis patients at 3 and 5 years. The performance of the model was evaluated using the consistency index (Harrell's C-index), the area under the receiver operating characteristic (ROC) curve, and calibration plots. The model was validated by tenfold cross-validation and bootstrapping with 1000 resamples. In the derivation cohort, the model yields an AUC of 0.764 [95% confidence interval (CI), 0.737-0.790] and 0.793 [CI, 0.757-0.829] for predicting the risk of cardiovascular events of MHD patients at 3 and 5 years. In the internal validation cohort AUC of 0.803 [95% CI, 0.756-0.849], AUC of 0.766 [95% CI, 0.686-0.846], and the external validation cohort AUC of 0.826 [95% CI, 0.765-0.888], AUC of 0.817 [95% CI, 0.745-0.889] at 3 and 5 years. The model's calibration curve is close to the ideal diagonal. By tenfold cross-validation analyses, the 3- and 5-year risk of cardiovascular events (AUC 0.732 and 0.771, respectively). By the bootstrap resampling method, the derivation cohort and validation cohort (Harrell's C-index 0.695 and 0.667, respectively) showed good uniformity with the model. The constructed model accurately predicted cardiovascular events of MHD patients in the 3rd and 5th years after dialysis. And the further research is needed to determine whether use of the risk prediction tool improves clinical outcomes.

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.

Mapping the global research landscape on malnutrition for patients with chronic kidney disease: a visualization analysis

BACKGROUND

Chronic kidney disease (CKD) is seen as a diverse disease and a primary contributor to global mortality. Malnutrition arises within chronic illness, which involves protein energy depletion and inadequate levels of essential nutrients. These factors increase the likelihood of death and the overall impact of the disease on affected individuals. Consequently, this study aims to utilize bibliometric and visual analysis to assess the current state of research, the latest advances and emerging patterns in the fields of CKD and malnutrition.

METHODS

Extensive research was conducted using the Scopus database, which is the most authoritative database of research publications and citations, to focus on CKD research between 2003 and 2022, as indicated by title and author keywords. Then, within this vast collection of academic publications, a notable subset of articles was exclusively dedicated to investigating the relationship between CKD and malnutrition. Finally, we performed bibliometric analysis and visualization using VOSviewer 1.6.19 and Microsoft Excel 2013.

RESULTS

Large global research between 2003 and 2022 resulted in 50,588 documents focused on CKD, as indicated by title and author keywords. In this extensive collection of scientific publications, a staggering portion of 823 articles is devoted exclusively to investigating the link between CKD and malnutrition. Further analysis reveals that this body of work consists of 565 articles (68.65%), 221 reviews (26.85%), and 37 miscellaneous entries (4.50%), which encompass letters and editorials. The USA was found to be the most productive country (n = 173; 21.02%), followed by Italy (n = 83; 10.09%), Sweden (n = 56; 6.80%), Brazil (n = 54; 6.56%) and China (n = 51; 6.20%). The most common terms on the map include those related to the topic of (a) malnutrition in hemodialysis patients and predicting factors; terms associated with the (b) impact of malnutrition on cardiovascular risk and complications in CKD patients; and terms related to the (c) dietary protein intake and malnutrition in CKD.

CONCLUSIONS

This study is the first of its kind to analyze CKD and malnutrition research using data from Scopus for visualization and network mapping. Recent trends indicate an increasing focus on protein-energy wasting/malnutrition in hemodialysis patients and predicting factors, dietary protein intake, and malnutrition in CKD. These topics have gained significant attention and reflect the latest scientific advances. Intervention studies are crucial to examining diet therapy's impact on patients with stages 1 to 5 CKD. We hope this study will offer researchers, dietitians and nephrologists valuable information.

Long-term body composition changes in patients undergoing hemodialysis: a single-center retrospective study

Background

Patients undergoing dialysis experience substantial decreases in muscle mass and functional muscle weakness. Muscle mass loss in patients undergoing hemodialysis is an independent predictor of survival, so muscle mass maintenance is essential for continued hemodialysis. This study examined longitudinal changes in the body composition of patients undergoing hemodialysis in different dialysis periods.

Methods

We retrospectively analyzed body composition measurements obtained by bioelectrical impedance analysis (BIA) using the same measuring instrument. The dialysis periods were 1–10 years from the start of hemodialysis for group A (n = 25), 10–20 years for group B (n = 22), and 20–30 years for group C (n = 9). The initial and final measurements of each group were compared. Furthermore, the nutritional status based on the inflammation and nutritional indicators obtained during the measurement period of each group was examined.

Results

Muscle mass did not significantly decrease in groups A and B but did decrease in group C (P < 0.05). In all groups, the extracellular water-to-total body water ratio (ECW/TBW) significantly increased (P < 0.001). C-reactive protein in groups A and B increased; however, the median initial and final values were < 0.2 mg/dL, and no changes were observed in group C. Furthermore, the median normalized protein catabolic rate was 0.86–1.05 g/kg/day, and there was no difference in the initial or final rates. The mean energy and protein daily intakes were 30–32 kcal/ideal body weight (IBW) kg/day and 1.1 g/IBW kg/day, respectively.

Conclusions

In patients undergoing hemodialysis, even if the muscle mass values are maintained, the possibility of a substantial decrease in muscle mass cannot be ruled out when ECW/TBW increases. Control of inflammation and nutritional intake may help minimize muscle mass loss caused by continued hemodialysis in patients.

Association of Abnormal Iron Status with the Occurrence and Prognosis of Peritoneal Dialysis-Related Peritonitis: A Longitudinal Data-Based 10-Year Retrospective Study

This retrospective study investigated the effect of iron status on peritonitis by analyzing longitudinal iron parameters in peritoneal dialysis (PD) patients. Patients who received PD at our center from 1 January 2006 to 31 December 2015 were included and followed up until 31 December 2017. According to the joint quartiles of baseline transferrin saturation and ferritin, iron status was categorized as reference iron status (RIS), absolute iron deficiency (AID), functional iron deficiency (FID), and high iron status (HIS). Generalized estimating equations and Cox regression models with time-dependent covariates were used. A total of 1258 PD patients were included; 752 (59.8%) were male, with a mean (±standard deviation) age of 47.4 (±14.9) years. During a median follow-up period of 35.5 (interquartile range, 18.4–60.0) months, 450 (34.3%) patients had 650 episodes of peritonitis. By analyzing longitudinal data, patients with AID were independently positively associated with the occurrence (adjusted odds ratio (AOR) = 1.45) and treatment failure of peritonitis (adjusted hazard ratio (AHR) = 1.85). Patients with HIS were positively associated with the treatment failure of peritonitis (AHR = 2.70). Longitudinal AID and HIS were associated with the episodes and poor prognosis of peritonitis. Active clinical monitoring and correction of iron imbalance in patients with PD are needed.

Total iron binding capacity is a predictor for muscle loss in maintenance hemodialysis patients

BACKGROUND

Protein-energy wasting in hemodialysis (HD) patients is characterized by decreased skeletal muscle mass and plasma protein. Some previous studies reported relationships between skeletal muscle dysfunction and iron deficiency. Dialysis patients with malnutrition may have a functional iron deficiency (FID) because of inflammation. Serum total iron binding capacity (TIBC), correlated with transferrin, is a nutritional status marker in HD patients and a biomarker of iron status. The relationship between muscle loss and iron status is unknown. The aim of the present study was to assess the relationship between iron status and change in skeletal muscle mass.

METHODS

A prospective cohort of 267 HD patients was examined for 12 months. Blood samples were obtained at baseline to measure TIBC, ferritin, transferrin saturation (TSAT), and hepcidin-25. Nutritional status and changes in muscle mass were assessed by subjective global assessment, albumin, creatinine index, and percentage creatinine generation rate.

RESULTS

At baseline, lower tertiles of TIBC were significantly related to lower muscle mass and albumin levels; they were also significantly correlated with high ferritin, hepcidin-25, and TSAT levels, as well as a higher proportion of use of erythropoiesis-stimulating agents. Multiple regression analysis adjusted with confounders showed TIBC was an independent biomarker for decreased muscle mass and albumin. Change in muscle mass remained significantly decreased in the lower tertile of TIBC and in malnourished patients.

CONCLUSIONS

The present study demonstrated relationships between FID and muscle loss. TIBC was an independent biomarker of muscle loss in HD patients, considering iron status, inflammation, oxidative stress, and malnutrition.

High-Normal Protein Intake Is Not Associated With Faster Renal Function Deterioration in Patients With Type 2 Diabetes: A Prospective Analysis in the DIALECT Cohort

OBJECTIVE

To study the prospective association between dietary protein intake and renal function deterioration in patients with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Prospective analyses were performed in data of 382 patients of the Diabetes and Lifestyle Cohort Twente (DIALECT) study. Dietary protein intake was determined by the Maroni equation from 24-h urinary urea excretion. Renal function deterioration was defined as need for renal replacement therapy or a persistent increase of ≥50% in serum creatinine. Cox proportional hazards models were used to calculate hazard ratios (HRs) for the association between dietary protein intake and renal function deterioration. Threshold levels represent the dietary protein intake at which there was a significantly increased and reduced hazard of renal function deterioration.

RESULTS

Renal function deterioration occurred in 53 patients (14%), with a median follow-up duration of 6 (interquartile range 5-9) years. Mean dietary protein intake was 91 ± 27 g/day (1.22 ± 0.33 g/kg ideal body weight/day). Dietary protein intake was inversely associated with renal function deterioration (HR 0.62 [95% CI 0.44-0.90]). Patients with an intake <92 g/day had an increased hazard for renal function deterioration (HR 1.44 [95% CI 1.00-2.06]), while patients with an intake >163 g/day had a decreased hazard for renal function deterioration (HR 0.42 [95% CI 0.18-1.00]). Regarding dietary protein intake per kilogram body weight, patients with an intake <1.08 g/kg/day had an increased hazard for renal function deterioration (HR 1.63 [95% CI 1.00-2.65]).

CONCLUSIONS

In patients with T2D, unrestricted dietary protein intake was not associated with an increased hazard of renal function deterioration. Therefore, substituting carbohydrates with dietary protein is not contraindicated as a part of T2D management, although it may have a positive effect on body weight while minimizing loss of muscle mass.

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.

Using a generic definition of cachexia in patients with kidney disease receiving haemodialysis: a longitudinal (pilot) study

BACKGROUND

Research indicates that cachexia is common among persons with chronic illnesses and is associated with increased morbidity and mortality. However, there continues to be an absence of a uniformed disease-specific definition for cachexia in chronic kidney disease (CKD) patient populations.

OBJECTIVE

The primary objective was to identify cachexia in patients receiving haemodialysis (HD) using a generic definition and then follow up on these patients for 12 months.

METHOD

This was a longitudinal study of adult chronic HD patients attending two hospital HD units in the UK. Multiple measures relevant to cachexia, including body mass index (BMI), muscle mass [mid-upper arm muscle circumference (MUAMC)], handgrip strength (HGS), fatigue [Functional Assessment of Chronic Illness Therapy (FACIT)], appetite [Functional Assessment of Anorexia/Cachexia Therapy (FAACT)] and biomarkers [C-reactive protein (CRP), serum albumin, haemoglobin and erythropoietin resistance index (ERI)] were recorded. Baseline analysis included group differences analysed using an independent t-test, dichotomized values using the χ2 test and prevalence were reported using the Statistical Package for the Social Sciences 24 (IBM, Armonk, NY, USA). Longitudinal analysis was conducted using repeated measures analysis.

RESULTS

A total of 106 patients (30 females and 76 males) were recruited with a mean age of 67.6 years [standard deviation (SD) 13.18] and dialysis vintage of 4.92 years (SD 6.12). At baseline, 17 patients were identified as cachectic, having had reported weight loss (e.g. >5% for >6 months) or BMI <20 kg/m2 and three or more clinical characteristics of cachexia. Seventy patients were available for analysis at 12 months (11 cachectic versus 59 not cachectic). FAACT and urea reduction ratio statistically distinguished cachectic patients (P = 0.001). However, measures of weight, BMI, MUAMC, HGS, CRP, ERI and FACIT tended to worsen in cachectic patients.

CONCLUSION

Globally, cachexia is a severe but frequently underrecognized problem. This is the first study to apply the defined characteristics of cachexia to a representative sample of patients receiving HD. Further, more extensive studies are required to establish a phenotype of cachexia in advanced CKD.

Predicational ability of phase angle on protein energy wasting in kidney disease patients with renal replacement therapy: A cross-sectional study

OBJECTIVE

To investigate the ability of phase angle (PA) and body composition for predicting protein energy wasting (PEW) in renal replacement therapy (RRT) patients.

METHODS

Renal replacement therapy (RRT) patients were enrolled in this study. Body composition was measured by direct segmental multi-frequency biolectrical impedance analysis method (DSM-BIA); phase angle (PA), fat-free mass (FFM), fat mass (FM), mid-arm circumference (MAC), WC (waist circumference), and ECW/TBW (extracellular water/total body water) were obtained. Biochemicals (serum albumin, triglyceride, and cholesterol) were tested. PEW patients were classified according to ISRNM (The International Society of Renal Nutrition and Metabolism) criteria. Cutoff value of PA and related variables was calculated by ROC analysis. The ability of body composition variables as indicators to predict PEW was evaluated.

RESULTS

Sixty-four patients were enrolled in this study. Thirty-three patients (52.6%) were males, and forty (62.5%) patients were diagnosed with PEW. The ROC curve showed that the optimal cutoff values of PA, FFMI (fat-free mass index), MAC, WC, and BMI for PEW risk were 4.45°, 16.71, 29.7 cm, 86.4 cm, and 21.1 kg/m2, respectively. These indicators showed significant association with PEW; meanwhile, the PA and MAC can be used as the predictors for PEW with OR 6.333 (95% CI, 1.956-20.505) and 3.267 (95% CI, 1.136-9.394), respectively. Both groups have a lower BUN/Cr ratio (<20).

CONCLUSION

In the RRT patients, over than 60% patients were diagnosed with PEW. PA, MAC, and other body composition can be used as the independent indicators for predicting PEW in renal replacement therapy kidney disease patients.

Skeletal myopathy in CKD: a comparison of adenine-induced nephropathy and 5/6 nephrectomy models in mice

Preclinical animal models of chronic kidney disease (CKD) are critical to investigate the underlying mechanisms of disease and to evaluate the efficacy of novel therapeutics aimed to treat CKD-associated pathologies. The objective of the present study was to compare the adenine diet and 5/6 nephrectomy (Nx) CKD models in mice. Male and female 10-wk-old C57BL/6J mice (n = 5-9 mice/sex/group) were randomly allocated to CKD groups (0.2-0.15% adenine-supplemented diet or 5/6 Nx surgery) or the corresponding control groups (casein diet or sham surgery). Following the induction of CKD, the glomerular filtration rate was reduced to a similar level in both adenine and 5/6 Nx mice (adenine diet-fed male mice: 81.1 ± 41.9 µL/min vs. 5/6 Nx male mice: 160 ± 80.9 µL/min, P = 0.5875; adenine diet-fed female mice: 112.9 ± 32.4 µL/min vs. 5/6 Nx female mice: 107.0 ± 45.7 µL/min, P = 0.9995). Serum metabolomics analysis indicated that established uremic toxins were robustly elevated in both CKD models, although some differences were observed between CKD models (i.e., p-cresol sulfate). Dysregulated phosphate homeostasis was observed in the adenine model only, whereas Ca2+ homeostasis was disturbed in male mice with both CKD models. Compared with control mice, muscle mass and myofiber cross-sectional areas of the extensor digitorum longus and soleus muscles were ∼18-24% smaller in male CKD mice regardless of the model but were not different in female CKD mice (P > 0.05). Skeletal muscle mitochondrial respiratory function was significantly decreased (19-24%) in CKD mice in both models and sexes. These findings demonstrate that adenine diet and 5/6 Nx models of CKD have similar levels of renal dysfunction and skeletal myopathy. However, the adenine diet model demonstrated superior performance with regard to mortality (∼20-50% mortality for 5/6 Nx vs. 0% mortality for the adenine diet, P < 0.05 for both sexes) compared with the 5/6 Nx surgical model.NEW & NOTEWORTHY Numerous preclinical models of chronic kidney disease have been used to evaluate skeletal muscle pathology; however, direct comparisons of popular models are not available. In this study, we compared adenine-induced nephropathy and 5/6 nephrectomy models. Both models produced equivalent levels of muscle atrophy and mitochondrial impairment, but the adenine model exhibited lower mortality rates, higher consistency in uremic toxin levels, and dysregulated phosphate homeostasis compared with the 5/6 nephrectomy model.

Testosterone Disorders and Male Hypogonadism in Kidney Disease

Chronic kidney disease (CKD) causes substantial alterations in the male endocrine system, which affect puberty, libido, and sexual function. A major effect of CKD is a reduction in testosterone levels because of both primary and hypogonadotrophic hypogonadism. In addition to impairment of pubertal growth and sexual maturation in children with CKD, clinical evidence suggests that uremic hypogonadism strongly contributes to several CKD complications, including erectile dysfunction, muscle wasting and frailty, anemia, decreased bone mineralization, depression, and cognitive impairment. This review focuses on a reappraisal of the physiologic role of testosterone, with an emphasis on the hypogonadal condition linked to CKD and its complications.

Low Protein Diets and Plant-Based Low Protein Diets: Do They Meet Protein Requirements of Patients with Chronic Kidney Disease?

A low protein diet (LPD) has historically been used to delay uremic symptoms and decrease nitrogen (N)-derived catabolic products in patients with chronic kidney disease (CKD). In recent years it has become evident that nutritional intervention is a necessary approach to prevent wasting and reduce CKD complications and disease progression. While a 0.6 g/kg, high biological value protein-based LPD has been used for years, recent observational studies suggest that plant-derived LPDs are a better approach to nutritional treatment of CKD. However, plant proteins are less anabolic than animal proteins and amino acids contained in plant proteins may be in part oxidized; thus, they may not completely be used for protein synthesis. In this review, we evaluate the role of LPDs and plant-based LPDs on maintaining skeletal muscle mass in patients with CKD and examine different nutritional approaches for improving the anabolic properties of plant proteins when used in protein-restricted diets.

Red Beetroot Betalains: Perspectives on Extraction, Processing, and Potential Health Benefits

In recent years, red beetroot has received a growing interest due to its abundant source of bioactive compounds, particularly betalains. Red beetroot betalains have great potential as a functional food ingredient employed in the food and medical industry due to their diverse health-promoting effects. Betalains from red beetroot are natural pigments, which mainly include either yellow-orange betaxanthins or red-violet betacyanins. However, betalains are quite sensitive toward heat, pH, light, and oxygen, which leads to the poor stability during processing and storage. Therefore, it is necessary to comprehend the impacts of the processing approaches on betalains. In this review, the effective extraction and processing methods of betalains from red beetroot were emphatically reviewed. Furthermore, a variety of recently reported bioactivities of beetroot betalains were also summarized. The present work can provide a comprehensive review on both conventional and innovative extraction techniques, processing methods, and the stability of betalains.

Association of Serum Indoxyl Sulfate Levels with Skeletal Muscle Mass and Strength in Chronic Hemodialysis Patients: A 2-year Longitudinal Analysis

Sarcopenia is highly prevalent in patients undergoing chronic hemodialysis (HD). This study investigated the relationship among serum indoxyl sulfate (IS) levels, muscle mass, and strength in HD patients. A total of 108 HD patients were enrolled. Skeletal muscle mass and handgrip strength (HGS) were assessed, using bioimpedance analysis and a hand-held dynamometer, respectively. Skeletal muscle index (SMI) was defined as skeletal muscle mass/height² (kg/m²). Serum IS, p-cresol sulfate (PCS), and trimethylamine N-oxide (TMAO) levels were determined using liquid chromatography-mass spectrometry. Patients were classified into two groups based on median serum IS values. HGS measurement was repeated after 2 years. Patients in the high IS group had longer HD duration and higher serum TMAO levels than those in the low IS group. Log-normalized IS level was negatively correlated with SMI (r = - 0.227; p = 0.018), but PCS and TMAO levels were not. Among 78 patients who completed 2-year follow-up, those in the high IS group (n = 41) showed greater absolute (- 2.48 kg versus - 0.25 kg, p = 0.035) and relative HGS loss (- 9.1% versus 1.4%, p = 0.036) than those in the low IS group, after adjustment for potential confounders. Indoxyl sulfate (IS) may play a significant role in uremic sarcopenia. Further large-scale studies are needed to confirm our preliminary findings.

Efeitos da doença e adequação da hemodiálise em pacientes com rigidez arterial

RESUMO Objetivos Analisar a adequação do tratamento hemodialítico em pacientes com rigidez arterial e associar os efeitos da doença renal com os fatores sociodemográficos e clínicos. Método Estudo epidemiológico, transversal realizado com 149 renais crônicos em tratamento de hemodiálise em hospital escola do interior do Estado de São Paulo. Utilizou-se para medida da rigidez arterial o aparelho de Dyna-MAPA®. Foram aplicados os testes de regressão linear multivariada, t Student e o qui-quadrado para os biomarcadores e a ocorrência de rigidez arterial. Resultados A maioria dos pacientes encontrava em idade produtiva, inativa profissionalmente, do sexo masculino, união estável, fazendo restrição hídrica e alimentar, com menos de 48 meses de tratamento dialítico; 36,9% dos pacientes apresentavam rigidez arterial. Os biomarcadores creatinina, ureia e fósforo estavam aumentados; hematócrito e hemoglobina estavam diminuídos, média de peso interdialítico de 2,34 ± 1,4 kg, e a maioria do Kt/V inadequado. Quanto aos efeitos da doença renal observou-se significância estatística com os inscritos na lista de transplantes, maior tempo de tratamento e aumento da creatinina. Conclusão Estes resultados podem proporcionar a diminuição da morbimortalidade cardiovascular nestes pacientes.

Cachexia/Protein energy wasting syndrome in CKD: Causation and treatment

Cachexia is a multifactorial syndrome defined by significant body weight loss, fat and muscle mass reduction, and increased protein catabolism. Protein energy wasting (PEW) is characterized as a syndrome of adverse changes in nutrition and body composition being highly prevalent in patients with CKD, especially in those undergoing dialysis, and it is associated with high morbidity and mortality in this population. Multiple mechanisms are involved in the genesis of these adverse nutritional changes in CKD patients. There is no obvious distinction between PEW and cachexia from a pathophysiologic standpoint and should be considered as part of the spectrum of the same nutritional disorder in CKD with similar management approaches for prevention and treatment based on current understanding. A plethora of factors can affect the nutritional status of CKD patients requiring a combination of therapeutic approaches to prevent or reverse protein and energy depletion. At present, there is no effective pharmacologic intervention that prevents or attenuates muscle atrophy in catabolic conditions like CKD. Prevention and treatment of uremic muscle wasting involve optimal nutritional support, correction of acidosis, and physical exercise. There has been emerging consistent evidence that active treatment, perhaps by combining nutritional interventions and resistance exercise, may be able to improve but not totally reverse or prevent the supervening muscle wasting and weakness. Active research into more direct pharmacological treatment based on basic mechanistic research is much needed for this unmet medical need in patients with CKD.

Sarcopenia is Associated with Malnutrition but Not with Systemic Inflammation in Older Persons with Advanced CKD

Background: In patients with chronic kidney disease (CKD), sarcopenia can be determined by a wide spectrum of risk factors. We evaluated the association of sarcopenia with nutritional, behavioral and inflammatory patterns in older patients with advanced CKD. Methods: we cross-sectionally evaluated 113 patients with CKD stages 3b-5. Sarcopenia was defined according to the EWGSOP2 criteria. We assessed: anthropometry, bioelectrical impedance analysis, physical, and psychological performance. Nutritional status was assessed using the Malnutrition Inflammation Score (MIS) and by verifying the eventual presence Protein Energy Wasting syndrome (PEW). Systemic inflammation was assessed by dosing: CRP, IL6, TNFα, MCP1, IL10, IL17, fetuin, IL12. Results: 24% of patients were sarcopenic. Sarcopenic individuals had lower creatinine clearance (18 ± 11 vs. 23 ± 19 mL/min; p = 0.0087) as well as lower BMI (24.8 ± 3.0 vs. 28.4 ± 5.5 Kg/m²; p < 0.0001) and a lower FTI (11.6 ± 3.9 vs. 14.4 ± 5.1 kg/m², p = 0.023). Sarcopenic persons had higher prevalence of PEW (52 vs. 20%, p < 0.0001) and a tendency to have higher MIS (6.6 ± 6.5 vs. 4.5 ± 4.0, p = 0.09); however, they did not show any difference in systemic inflammation compared to non-sarcopenic individuals. Conclusions: CKD sarcopenic patients were more malnourished than non-sarcopenic ones, but the two groups did not show any difference in systemic inflammation.

Hypoproteinemia as a factor in assessing malnutrition and predicting survival on hemodialysis

Series of studies have described malnutrition as one of the main non-traditional risk factors associated with poor prognosis and treatment outcome in patients on hemodialysis (HD). The aims of this study were to evaluate the link between HD treatment quality and the nutritional status and to additionally investigate the association of malnutrition and overall survival. A total of 134 adult out-patients (56.4% male, mean age 60.8 ± 16.15 years) were enrolled in the study. Clinical and laboratory data were obtained from the medical records. Anthropometric measurements were performed prior to HD. Malnutrition-Inflammation Score (MIS) was used as a scoring system representing the severity of protein-energy wasting (PEW). Malnourished patients were significantly older when compared to non-malnourished patients. They had significantly longer dialysis vintage and lower residual diuresis, BMI, serum proteins, and albumins and lean tissue index (LTI). Malnourished patients survived significantly shorter than non-malnourished patients. Hypoproteinemic patients had significantly lower values of serum albumins and LTI and survived shorter than normoproteinemic patients. Only malnourishment and age were associated with higher overall mortality in all groups of patients. By focusing on MIS and serum protein status rather than dialysis-related factors and different treatment techniques, we could accomplish better nutrition status and improved overall outcomes. While anticipating new and more effective measures for preventing malnutrition, our results clearly demonstrate that striving for the highest possible nutrition status should be one of the key strategies in improving the outcomes in this specific group of patients.

ENHO, RXRA, and LXRA polymorphisms and dyslipidaemia, related comorbidities and survival in haemodialysis patients

BACKGROUND

The energy homeostasis-associated gene (ENHO), retinoid X receptor alpha gene (RXRA), and liver X receptor alpha gene (LXRA) are involved in adipogenic/lipogenic regulation. We investigated whether single-nucleotide polymorphisms in these genes (ENHO rs2281997, rs72735260; RXRA rs749759, rs10776909, rs10881578; LXRA rs2279238, rs7120118, rs11039155) are associated with dyslipidaemia, related comorbidities and survival of haemodialysis (HD) patients also tested for T-helper (Th) cell interleukin genes (IL).

METHODS

The study was carried out in 873 HD patients. Dyslipidaemia was diagnosed by the recommendations of the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines (2003); atherogenic dyslipidaemia was referred to if the TG/HDL cholesterol ratio was equal to or higher than 3.8. Genotyping of ENHO SNPs, LXRA SNPs, and IL12A rs568408 was carried out using HRM analysis. RXRA SNPs, IL12B rs3212227, and IL18 rs360719 were genotyped using PCR-RFLP analysis. The circulating adropin concentration was determined in 126 patients by enzyme-linked immunosorbent assay. Survival probability was analysed using the Kaplan-Meier method in 440 patients followed through 7.5 years.

RESULTS

Dyslipidaemia by K/DOQI was diagnosed in 459 patients (91% revealed hyper-LDL- cholesterolaemia), atherogenic dyslipidaemia was diagnosed in 454 patients, and 231 patients were free of dyslipidaemia by both criteria. The variant allele (T) of ENHO rs2281997 was associated with the hyper-LDL cholesterolaemic pattern of dyslipidaemia by K/DOQI. The frequency of atherogenic dyslipidaemia was lower in T-allele bearers than in CC-genotype patients. The rs2281997 T allele was associated with lower cardiovascular mortality in HD patients showing atherogenic dyslipidaemia. ENHO, RXRA, and LXRA showed epistatic interactions in dyslipidaemia. Circulating adropin was lower in atherogenic dyslipidaemia than in non-atherogenic conditions. RXRA rs10776909 was associated with myocardial infarction. Bearers of LXRA rs2279238, rs7120118 or rs11039155 minor alleles showed higher mortality. ENHO SNP positions fell within the same DNase 1 hypersensitivity site expressed in the Th1 cell line. Epistatic interactions occurred between rs2281997 and Th1 IL SNPs (rs360719, rs568408).

CONCLUSIONS

Atherogenic dyslipidaemia occurs in HD patients in whom ENHO encodes less adropin. ENHO, RXRA, and LXRA SNPs, separately or jointly, are associated with dyslipidaemia, myocardial infarction, and survival in HD patients. Differences in the availability of transcription binding sites may contribute to these associations.

Biochemical evidence of cell starvation in diabetic hemodialysis patients

Recently, the ratio of patients with diabetes mellitus (DM) among hemodialysis (HD) patients has increased to become the largest sub-population. Their prognoses are significantly worse than those of patients without diabetes (non-DM). In the present study, 10 DM patients who did not take meals and 10 non-DM patients who took meals during HD sessions were investigated. The time courses of the change in plasma levels of metabolites during HD were determined. DM patients exhibited decreased plasma levels of lactate, pyruvate and alanine and dramatically increased levels of ketone bodies. At the end of HD, the plasma levels of lactate, pyruvate, alanine and ketone body were 0.46 ± 0.07, 0.026 ± 0.01, 0.12 ± 0.04 and 0.26 ± 0.04 mM (mean ± standard error), respectively. The profile was ‘hypolactatemia and hyperketonemia’, indicating non-homeostasis. Glycolysis and tricarboxylic acid cycle were suppressed, and the oxidation of fatty acid was accelerated, indicating starvation, even though high amounts of glucose (150 mg/dl) in dialysate were supplied continuously to the bloodstream. In contrast, the plasma levels of lactate, pyruvate, and alanine in the non-DM patients were increased, with the levels of ketone body remaining low during HD to maintain homeostasis, indicating accelerated glycolysis. Furthermore, their plasma levels of insulin increased from 8.1 ± 1.4 to 19.8 ± 3.4 μU/ml, which indicated endogenous secretion stimulated by glucose in dialysate and meal intake. In contrast, in the DM patients, the levels decreased from 19.2 ± 3.4 to 5.5 ± 1.1 μU/ml. This value was the lower limit of the normal range. The depletion of the insulin through extracorporeal circulation may inhibit the transportation of glucose from the blood into the muscles, with the consequence of cell starvation. Such cell starvation along with lipolysis every two days may accelerate proteolysis and affect the prognosis of DM patients.

Malnutrition associated with inflammation in the chronic renal patient on hemodialysis

SUMMARY INTRODUCTION Malnutrition-Inflammation-Atherosclerosis Syndrome is very frequent in patients with chronic kidney disease on haemodialysis. In these patients, the inflammation associated with malnutrition is observed by the Malnutrition-Inflammation Score. OBJECTIVE To analyse the relationship between malnutrition-inflammation-atherosclerosis syndrome and anthropometric and biochemical parameters of patients on haemodialysis. METHODS A cross - sectional study was performed at the Haemodialysis Clinic of the Barão de Lucena Hospital, Recife, Brazil, between July and August 2016, with patients cared at the clinic for at least six months. Patients with amputees, hospitalized, visually impaired, HIV positive, with catheters in the neck, ascites and/or oedema, and those who were unable to provide information at the time of the interview were excluded. The patients were submitted to anthropometric evaluation for the classification of the nutritional status by waist circumference, neck circumference, body mass index, waist-to-hip ratio and waist-to-height ratio. Nutritional status related to inflammation was measured by the Malnutrition-Inflammation Score and nutritional status assessment using biochemical indicators that used urea, creatinine and albumin. RESULTS Twenty-seven individuals of both genders, adults and elderly, aged 51.3 ± 13.3 years old participated in the study. The anthropometric evaluation showed that most of the population presented cardiovascular risk. The biochemical evaluation reported low frequencies of malnutrition. Malnutrition-Inflammation-Atherosclerosis syndrome was evidenced in 3.7% of the patients. The Malnutrition-Inflammation Score had a moderate negative correlation with body mass index, waist circumference, neck circumference, waist-to-height ratio and creatinine. CONCLUSION The correlation seen among the parameters suggests that most of the parameters evaluated can be used as an indirect indicator of malnutrition-inflammation-atherosclerosis syndrome.

Diminishing dry weight is strongly associated with all-cause mortality among long-term maintenance prevalent dialysis patients

Objectives

To investigate the relationship between dry weight (DW) change and survival in long-term maintenance prevalent dialysis patients.

Methods

We conducted a prospective data collection study with retrospective analysis of the registered data. Patients were followed up for 5 years (1-year observation of DW changes and subsequent 4-year follow-up). The outcome was all-cause mortality. The predictors were 1-year DW change rates. The hazard ratios (HRs) for all-cause mortality were calculated using multivariable Cox regression analysis, fully adjusted for age, sex, basal kidney disease, dialysis vintage, current smoking, past cardiovascular events, serum albumin, DW at enrollment, serum creatinine, mean predialysis systolic blood pressure, and cardiothoracic ratio or 1-year cardiothoracic ratio change rate. Propensity score (PS) analysis was also conducted using the same covariates of Cox regression analysis.

Results

In total, 899 dialysis patients (mean dialysis vintage: 101.2 months) were followed up, and 180 deaths were recorded, of which 90 were of cardiovascular origin. Each 2% decrement of DW showed adjusted HR, and the 95% confidence interval was 1.24 [1.16–1.33]. According to the 1-year DW change rate, participants were divided into five groups (group A, ≥+3%; group B, +1 to +2.9%; group C, -0.9 to +0.9%; group D, -2.9 to -1.0%; and group E, ≤-3%). For survival curves based on grouping, group B had the best and group E had the worst survival rate (p<0.01, log-rank test). Therefore, we set group B as a reference; adjusted risks for death of groups D and E were 2.16 [1.23–3.79] and 2.66 [1.54–4.58], respectively. However, this relation was blunted in patients of heavier DW. The PS-matched cohort showed a poorer prognosis in patients with diminishing DW divided by DW change rate at -0.635% (mean value of DW change rate).

Conclusion

In the long-term maintenance hemodialysis cohort, 1-year DW decrement, especially ≤-3.0%, was significantly associated with all-cause mortality, and cardiovascular disease-related death was prominent in these patients.

Application of liquisolid technology for promoting the renoprotective efficacy of walnut extracts in chronic renal failure rat model

Chronic renal failure (CRF) is among the major health problems that could lead to increased morbidity and mortality among population. 'Nutraceuticals' is an emerging field for natural agents from plant foods that could reduce the progression of such disease. Many newly developed drugs are having bioavailability problems owing to their water insolubility. Liquisolid technique is one of the promising technological approaches to increase solubility and hence, drug absorption. The aim of the present research is to prepare and evaluate the renoprotective effect of the walnut extracts liquisolid formulations in CRF rat model. Saturation solubility study claimed PEG 400 and Tween 20 as good solubilizers for walnut extracts, thus chosen for preparation. The angle of slide was determined for the carrier; microcrystalline cellulose and coating material; silicon dioxide and liquid load factor was evaluated. Eight liquisolid systems were prepared employing 25% and 50% of liquid medication. Their flow and compressibility parameters showed good properties. Dissolution study was more in favor of formulations prepared using PEG 400. Of these, formulation F8 comprising carrier/coat ratio (10:1) and 50% liquid medication, showing superior dissolution properties was selected to perform stability and in-vivo evaluations. Two CRF induced rat groups received F8 at two oral doses (50 and 100 mg/kg). Biochemical and nutritional parameters were compared with both normal and CRF control rats. Results showed improvement of renal function, oxidative stress, antioxidant and inflammatory biomarkers as well as increased appetite and body weight gain on administration of both doses of walnut liquisolid formulation, F8.

Evaluation of Body Composition in Hemodialysis Thai Patients: Comparison between Two Models of Bioelectrical Impedance Analyzer and Dual-Energy X-Ray Absorptiometry

Background

Body composition measurement is very important for early nutritional care in hemodialysis patients. Dual-energy X-ray absorptiometry (DXA) is a gold standard test, but clinically limited. Bioelectrical impedance analysis (BIA) with multifrequency technique is a practical and reliable tool.

Objective

This cross-sectional study was aimed to compare the agreement of BIA with DXA in measurement of body composition in hemodialysis patients and to evaluate their associated factors.

Methods

Body composition was measured by 2 BIA methods (InBody S10 and InBody 720) and DXA after a hemodialysis session. A total of 69 measurements were included. Pearson's correlation and Bland and Altman analysis were used to determine the correlation of body composition between methods and to compare the methods agreement, respectively.

Results

The correlation coefficients of body compositions were strong between DXA and InBody S10 (fat mass index (FMI): r=0.95, fat-free mass index (FFMI): r=0.78) and also between DXA and InBody 720 (FMI: r=0.96, FFMI: r=0.81). Comparing to DXA, the means of each body composition measured by InBody S10 method were not significantly different in each gender, but differences were found in FM, %FM, and FMI measured by InBody 720.

Conclusions

In maintenance hemodialysis patients, the measurement of body composition with DXA and both BIA methods had highly significant correlations; practically, BIA method could be used as an instrument to follow FM and FFM and to measure the edematous stage. Further studies with large populations are warranted.

Obesity may be erythropoietin dose-saving in hemodialysis patients

Background

In dialysis patients, the obesity-survival paradox still requires an explanation. Anemia and high doses of erythropoiesis-stimulating agents (ESAs) are associated with worse outcomes in the hemodialysis (HD) population. In the present study, we explored the relation between obesity and anemia control in a sample of maintenance HD patients in Egypt.

Methods

This multicenter observational study included 733 patients on maintenance HD from 9 hemodialysis centers in Egypt. Clinical and laboratory data as well as average doses of ESAs and parenteral iron were recorded. The erythropoietin resistance index (ERI) was calculated.

Results

Obesity, defined as a body mass index (BMI) ≥ 30 kg/m², was present in 22.6% of the studied population. The target hemoglobin level (10.0–11.5 g/dL) was achieved in 27.3% of non-obese and 25.3% of obese patients, with no significant difference. The median serum ferritin and the values of transferrin saturation index did not differ significantly between these two groups. The weekly ESA dose was significantly lower in obese than in non-obese patients (P = 0.0001). A trend toward higher ESA doses and ERI values was observed in patients with lower BMIs (P < 0.0001). Multiple linear regression revealed that the BMI and urea reduction ratio were the strongest predictors of the ERI.

Conclusion

Our study adds more evidence to obesity-associated advantages in HD patients. BMI may determine ESA response, with better responses observed in patients with higher BMIs.

Comparison of Subjective Global Assessment and Protein Energy Wasting Score to Nutrition Evaluations Conducted by Registered Dietitian Nutritionists in Identifying Protein Energy Wasting Risk in Maintenance Hemodialysis Patients

OBJECTIVE

To compare the 7-point subjective global assessment (SGA) and the protein energy wasting (PEW) score with nutrition evaluations conducted by registered dietitian nutritionists in identifying PEW risk in stage 5 chronic kidney disease patients on maintenance hemodialysis.

DESIGN AND METHODS

This study is a secondary analysis of a cross-sectional study entitled "Development and Validation of a Predictive energy Equation in Hemodialysis". PEW risk identified by the 7-point SGA and the PEW score was compared against the nutrition evaluations conducted by registered dietitian nutritionists through data examination from the original study (reference standard).

SUBJECTS

A total of 133 patients were included for the analysis.

MAIN OUTCOME MEASURES

The sensitivity, specificity, positive and negative predictive value (PPV and NPV), positive and negative likelihood ratio (PLR and NLR) of both scoring tools were calculated when compared against the reference standard.

RESULTS

The patients were predominately African American (n = 112, 84.2%), non-Hispanic (n = 101, 75.9%), and male (n = 80, 60.2%). Both the 7-point SGA (sensitivity = 78.6%, specificity = 59.1%, PPV = 33.9%, NPV = 91.2%, PLR = 1.9, and NLR = 0.4) and the PEW score (sensitivity = 100%, specificity = 28.6%, PPV = 27.2%, NPV = 100%, PLR = 1.4, and NLR = 0) were more sensitive than specific in identifying PEW risk. The 7-point SGA may miss 21.4% patients having PEW and falsely identify 40.9% of patients who do not have PEW. The PEW score can identify PEW risk in all patients, but 71.4% of patients identified may not have PEW risk.

CONCLUSIONS

Both the 7-point SGA and the PEW score could identify PEW risk. The 7-point SGA was more specific, and the PEW score was more sensitive. Both scoring tools were found to be clinically confident in identifying patients who were actually not at PEW risk.

Clinical relevance of sarcopenia in chronic kidney disease

PURPOSE OF REVIEW

In this article, we review sarcopenia in chronic kidney disease (CKD). We aim to present how definitions of sarcopenia from the general population may pertain to those with CKD, its assessment by clinicians and emerging therapies for sarcopenia in CKD. For this review, we limit our description and recommendations to patients with CKD who are not on dialysis.

RECENT FINDINGS

Poorer parameters of lean mass, strength and physical function are associated with worsening patient-centered outcomes such as limiting mobility, falls and mortality in CKD; however, the magnitude of these associations are different in those with and without CKD. Sarcopenia in CKD is a balance between skeletal muscle regeneration and catabolism, which are both altered in the uremic environment. Multiple pathways are involved in these derangements, which are briefly reviewed. Differences between commonly used terms cachexia, frailty, protein-energy wasting, dynapenia and sarcopenia are described. Therapeutic options in predialysis CKD are not well studied; therefore, we review exercise options and emerging pharmacological therapies.

SUMMARY

Sarcopenia, now with its own International Classification of Diseases, 10th Revision (ICD-10) code, is of importance clinically and should be accounted for in research studies in patients with CKD. Multiple therapies for sarcopenia are in development and will hopefully be available for our patients in the future.

Effects of a Novel Nutritional Formula Enriched With Eicosapentaenoic Acid and Docosahexaenoic Acid Specially Developed for Tube-Fed Hemodialysis Patients

OBJECTIVE

To evaluate the effects of a nutritional formula enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in tube-fed bedridden hemodialysis patients.

DESIGN

A prospective, multicenter, single-arm study.

SETTING

Koyukai Memorial Hospital, Orimoto Hospital, and Chofu Hospital, Japan.

SUBJECTS

Eleven tube-fed bedridden hemodialysis patients.

INTERVENTION

Patients were fed a nutritional formula enriched with EPA and DHA for 12 weeks.

MAIN OUTCOME MEASURES

Body weight; body mass index (BMI); serum levels of total protein, albumin, prealbumin, total cholesterol, triglyceride, and C-reactive protein (CRP); serum fatty acid composition.

RESULTS

Body weight; BMI; and serum levels of total protein, albumin, total cholesterol, triglyceride, and CRP at 12 weeks were not significantly different from baseline levels. Serum prealbumin, EPA, and DHA levels significantly increased after 12 weeks of treatment.

CONCLUSIONS

A nutritional formula enriched with EPA and DHA may be beneficial for nutritional management in tube-fed bedridden hemodialysis patients.

Effects of Resveratrol Supplementation in Nrf2 and NF-κB Expressions in Nondialyzed Chronic Kidney Disease Patients: A Randomized, Double-Blind, Placebo-Controlled, Crossover Clinical Trial

INTRODUCTION

Resveratrol is a phenolic compound that has demonstrated anti-inflammatory and antioxidant effects, resulting from enhanced antioxidant enzymes production and modulating nuclear factors involved in the inflammation-oxidative stress cycle, as nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB).

OBJECTIVE

The study aim was to evaluate the effects of resveratrol supplementation on Nrf2 and NF-κB expression in nondialyzed chronic kidney disease (CKD) patients.

MATERIALS AND METHODS

A randomized, double-blind, crossover trial was performed in 20 nondialyzed CKD patients (62.0 ± 8.0 years old, 45% men, body mass index of 27.7 ± 1.2 kg/m², estimated glomerular filtration rate of 34.0 ± 13.0 mL/minute). Eleven patients were randomly allocated to "placebo first" (4 weeks placebo; 8 weeks washout, 4 weeks 500 mg of resveratrol/day) and 9 to "resveratrol first" (4 weeks 500 mg of resveratrol/day, 8 weeks washout, 4 weeks placebo). The peripheral blood mononuclear cells were isolated and processed for expression Nrf2 and NF-κB by quantitative real-time polymerase chain reaction. Proinflammatory cytokines and antioxidant enzymes were also measured.

RESULTS

The effect size of Nrf2 supplementation (-0.13, P = .29) and NF-κB (0.09, P = .31) was not significant. There was no difference in proinflammatory biomarkers or antioxidant biomarkers after resveratrol supplementation.

CONCLUSION

In this pilot study, 500 mg of resveratrol supplementation for 4 weeks had no antioxidant and anti-inflammatory effect in nondialyzed CKD patients. Additional studies with differing doses and/or time of treatment should be conducted to better elucidate the effects of the resveratrol supplementation in CKD patients.

The effects of resistance exercise and oral nutritional supplementation during hemodialysis on indicators of nutritional status and quality of life

BACKGROUND

Protein-energy wasting (PEW) is common in patients undergoing hemodialysis (HD). Studies have assessed the positive effect of oral nutritional supplementation (ONS) or resistance exercise (RE) on nutritional status (NS) markers in patients undergoing HD.

METHODS

The aim of this study was to assess the effect of ONS and RE on NS and the quality of life (QOL) of 36 patients undergoing HD. In a randomized clinical trial, patients were divided into the following two groups: a control group (ONS) that received a can of ONS during their HD sessions and an intervention group (ONS + RE) that received a can of ONS and underwent a 40-min session of RE during their HD sessions. Both interventions lasted 12 weeks. The patients' anthropometric, biochemical, dietetic and bioelectrical impedance measurements as well as their QOL, evaluated using the Kidney Disease Quality of Life Short Form, were recorded.

RESULTS

At baseline, 55.5% of patients presented with PEW according to International Society of Renal Nutrition and Metabolism criteria (20 patients). We found statistically significant changes from baseline in both groups, such as increases in body weight, body mass index, midarm circumference, midarm muscle circumference, triceps skinfold thickness, fat mass percentage, handgrip strength, phase angle and serum albumin. A decrease in the prevalence of PEW was observed in both groups at the end of the intervention. A delta comparison between groups showed no statistically significant differences in the anthropometric and biochemical parameters. No significant improvement was observed in QOL and body composition measured by bioimpedance vector analysis. Dietary energy and protein intake increased significantly during the study period for all patients.

CONCLUSION

Oral nutritional supplementation during HD improves NS. The addition of RE during HD does not seem to augment the acute anabolic effects of intradialytic ONS on NS.

Hepatocyte growth factor (HGF) and hemodialysis: physiopathology and clinical implications

Hepatocyte growth factor (HGF) is a pleiotropic cytokine which exerts a variety of effects on several cells, being involved in the regulation of many biological processes, such as inflammation, tissue repair, morphogenesis, angiogenesis, tumour propagation, immunomodulation of viral infections and cardio-metabolic activities. Patients undergoing regular hemodialysis (HD) present elevated levels of HGF, mainly due to the leukocyte activation associated with HD treatment. High HGF levels might account for specific clinical features of HD patients, i.e. mild liver damage in course of HCV-infection and high cardiovascular risk profile. Moreover, in patients with acute kidney injury, the induction of HGF may represent a crucial step to promote renal recovery, which can have important prognostic consequences in the short and long-term. In this review we discuss the mechanisms underlying HGF production in HD patients, the role of HGF in this particular patient population and the potential clinical implications derived from the study of HGF in HD patients.

Sarcopenia and Physical Inactivity in Patients With Chronic Kidney Disease

Sarcopenia and physical inactivity synergistically progress in patients with chronic kidney disease (CKD) and are strong predictors of mortality in this population. Exercise training and essential amino acids and vitamin D supplements may contribute to improving sarcopenia and physical inactivity in CKD patients.

The Associations of Malnutrition and Aging with Fluid Volume Imbalance between Intra- and Extracellular Water in Patients with Chronic Kidney Disease

OBJECTIVES

Fluid imbalance due to sodium retention and malnutrition can be characterized by the ratio of extracellular water (ECW) to intracellular water (ICW). We investigated whether the ECW/ICW ratio is a risk factor for adverse outcomes.

DESIGN

Retrospective cohort study.

SETTING AND PARTICIPANTS

149 patients with chronic kidney disease from 2005 to 2009, who were followed until August 2013.

MEASUREMENTS

Body fluid composition was measured by bioelectrical impedance analysis. Patients were categorized according to the ECW/ICW ratio tertile. Daily nutrient intake was estimated from 24-h dietary recall and analyzed using standard food composition tables. The main outcomes were adverse renal outcomes, as defined by a decline of 50% or more from the baseline glomerular filtration rate or initiation of renal replacement therapy, cardiovascular events, and all-cause mortality.

RESULTS

The ECW/ICW ratio increased with downward ICW slope with age and renal dysfunction besides ECW excess with massive proteinuria. Sodium intake, protein intake, and calorie intake were negatively correlated with the ECW/ICW ratios due to the steeper decreasing ICW content with the decreased dietary intake than the decreasing ECW content. During a median 4.9-year follow up, patients in the highest tertile had the worst adverse renal outcomes (15.9 vs. 5.1 per 100 patient-years, P < 0.001), cardiovascular events (4.1 vs. 0.3 per 100 patient-years, P = 0.002), and mortality (11.2 vs. 1.3 per 100 patient-years, P < 0.001). The adjusted hazard ratio (95% confidence intervals) for adverse renal outcomes, cardiovascular events, and mortality were 1.15 (1.03 - 1.26), 1.12 (0.93 - 1.31), and 1.29 (1.11 - 1.50), respectively.

CONCLUSIONS

Fluid imbalance between ICW and ECW occurring in malnourished and elderly patients with chronic kidney disease may explain the reserve capacity for volume overload and is associated with adverse renal outcomes and all-cause mortality.

Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients

Background

n-3 polyunsaturated fatty acids (PUFAs) might be useful nutritional strategy for treating patients with sarcopenia. We evaluated the effect of the intake of dietary n-3 PUFAs on the skeletal muscle mass (SMM), appendicular skeletal muscle mass (ASM), and its determinants in patients receiving standard hemodialysis (HD) treatment for the management of end stage renal disease.

Methods

In this cross-sectional study, data of 111 HD patients were analyzed. Anthropometric and bioelectrical impedance measurements used to estimate the muscle mass were performed the day of dialysis immediately after the dialysis session. Routine laboratory and 3-day dietary data were also collected. The cutoff value of adequate intake (AI) for both n-3 PUFAs and alpha-linolenic acid (ALA) was 1.6 g/day and 1.1 g/day for men and women, respectively.

Results

The mean age, mean dietary n-3 PUFAs intake, ALA intake, ratio of n-6/n-3 PUFAs intake, SMM, and ASM of patients were 61.4 ± 10.4 years, 2.0 ± 1.3 g/day, 1.5 ± 1.0 g/day, 9.5 ± 6.7 g/day, 23.9 ± 5.5 kg, and 17.5 ± 4.5 kg, respectively. A higher SMM and ASM significantly observed in patients who achieved an AI of n-3 PUFAs. Similar trends appeared to be observed among those patients who achieved the AI of ALA, but the difference was not significantly, except for ASM (P = 0.047). No relevant differences in demographics, laboratory and nutritional parameters were observed, regardless of whether the patients achieved an AI of n-3 PUFAs. Multivariate analysis showed that the BMI and equilibrated Kt/V were independent determinants of the muscle mass. Moreover, the ratio of n-6/n-3 PUFAs was an independent risk determinant of reduced ASM in HD patients.

Conclusion

Patients with an AI of n-3 PUFAs had better total-body SMM and ASM. A higher dietary ratio of n-6/n-3 PUFAs seemed to be associated with a reduced muscle mass in HD patients.

Fiber type-specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients

INTRODUCTION

The aim of this study was to assess the effect of high-intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis.

METHODS

Patients (n = 21) underwent a 16-week control period, followed by 16 weeks of resistance training 3 times weekly. SC and myonuclear number were determined by immunohistochemistry of vastus lateralis muscle biopsy cross-sections. Knee extension torque was tested in a dynamometer.

RESULTS

During training, SCs/type I fibers increased by 15%, whereas SCs/type II fibers remained unchanged. Myonuclear content of type II, but not type I, fibers increased with training. Before the control period, the SC content of type II fibers was lower than that of type I fibers, whereas contents were comparable when normalized to fiber area. Torque increased after training.

CONCLUSIONS

Increased myonuclear content of type II muscle fibers of dialysis patients who perform resistance training suggests that SC dysfunction is not the limiting factor for muscle growth.

Study of Serum Levels of Leptin, C-Reactive Protein and Nutritional Status in Hemodialysis Patients

Background:

Leptin is secreted by adipose tissue and decreases appetite. However, the role of leptin in the pathogenesis of hemodialysis (HD)-related malnutrition has not been fully evaluated.

Objectives:

The aim of study was to investigate the association between the serum leptin levels, serum C-reactive protein (CRP) levels, and nutritional status in hemodialysis patients.

Patients and Methods:

This analytical descriptive study included 45 hemodialysis patients and 40 healthy subjects. Biochemical parameters and serum leptin levels were measured. The nutritional status was evaluated using a food frequency questionnaire (FFQ) and the calculation of the body mass index (BMI).

Results:

Serum leptin (P < 0.05) and albumin (P < 0.0001) levels and BMI (P < 0.001) of HD patients were significantly lower, while CRP levels were significantly higher than those of controls (P < 0.0001). HD patients consumed the lower daily servings of the food groups compared to the control subjects (P < 0.0001). A significant positive correlation between serum levels of leptin and albumin and BMI was demonstrated. No significant correlations were identified between leptin level, CRP level, and other variables.

Conclusions:

The findings suggest that low levels of leptin may be a contributory factor for malnutrition in HD patients. Further studies are required to ascertain the significance of leptin levels in relation to nutritional factors in hemodialysis patients.

Heart Rate Variability Correlates to Functional Aerobic Impairment in Hemodialysis Patients

Background

Autonomic dysfunction (AD) is highly prevalent in hemodialysis (HD) patients and has been implicated in their increased risk of cardiovascular mortality.

Objective

To correlate heart rate variability (HRV) during exercise treadmill test (ETT) with the values obtained when measuring functional aerobic impairment (FAI) in HD patients and controls.

Methods

Cross-sectional study involving HD patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT were performed. A symptom-limited ramp treadmill protocol with active recovery was employed. Heart rate variability was evaluated in time domain at exercise and recovery periods.

Results

Forty-one HD patients and 41 controls concluded the study. HD patients had higher FAI and lower HRV than controls (p<0.001 for both). A correlation was found between exercise HRV (SDNN) and FAI in both groups. This association was independent of age, sex, smoking, body mass index, diabetes, and clonidine or beta-blocker use, but not of hemoglobin levels.

Conclusion

No association was found between FAI and HRV on 24-hour Holter or at the recovery period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD patients and controls.

Detection of autonomic dysfunction in hemodialysis patients using the exercise treadmill test: the role of the chronotropic index, heart rate recovery, and R-R variability

OBJECTIVE

To evaluate the ability of different parameters of exercise treadmill test to detect autonomic dysfunction in hemodialysis patients.

METHODS

Cross-sectional study involving hemodialysis patients and a control group. Clinical examination, blood sampling, echocardiogram, 24-hour Holter, and exercise treadmill test were performed. A ramp treadmill protocol symptom-limited with active recovery was employed.

RESULTS

Forty-one hemodialysis patients and 41 controls concluded the study. There was significant difference between hemodialysis patients and controls in autonomic function parameters in 24h-Holter and exercise treadmill test. Probability of having autonomic dysfunction in hemodialysis patients compared to controls was 29.7 at the exercise treadmill test and 13.0 in the 24-hour Holter. Chronotropic index, heart rate recovery at the 1st min, and SDNN at exercise were used to develop an autonomic dysfunction score to grade autonomic dysfunction, in which, 83% of hemodialysis patients reached a scoring ≥2 in contrast to 20% of controls. Hemodialysis was independently associated with either altered chronotropic index or autonomic dysfunction scoring ≥2 in every tested model (OR=50.1, P=0.003; and OR=270.9, P=0.002, respectively, model 5).

CONCLUSION

The exercise treadmill test was feasible and useful to diagnose of the autonomic dysfunction in hemodialysis patients. Chronotropic index and autonomic dysfunction scoring ≥2 were the most effective parameters to differentiate between hemodialysis patients and controls suggesting that these variables portrays the best ability to detect autonomic dysfunction in this setting.

Muscle wasting in end-stage renal disease promulgates premature death: established, emerging and potential novel treatment strategies

Muscle wasting (or sarcopenia) is a common feature of the uremic phenotype and predisposes this vulnerable patient population to increased risk of comorbid complications, poor quality of life, frailty and premature death. The old age of dialysis patients is in addition a likely contributor to loss of muscle mass. As recent evidence suggests that assessment of muscle strength (i.e. function) is a better predictor of outcome and comorbidities than muscle mass, this opens new screening, assessment and therapeutic opportunities. Among established treatment strategies, the benefit of resistance exercise and endurance training are increasingly recognized among nephrologists as being effective and should be promoted in sedentary chronic kidney disease patients. Testosterone and growth hormone replacement appear as the most promising among emerging treatments strategies for muscle wasting. As treatment of muscle wasting is difficult and seldom successful in this often old, frail, sedentary and exercise-hesitant patient group, novel treatment strategies are urgently needed. In this review, we summarize recent studies on stimulation of mitochondrial biogenesis, myogenic stem (satellite) cells and manipulation of transforming growth factor family members, all of which hold promise for more effective therapies to target muscle mass loss and function in the future.