Adipokines and nutritional status for patients on maintenance hemodialysis

Skeletal muscle atrophy in clinical and preclinical models of chronic kidney disease: A systematic review and meta-analysis

Patients with chronic kidney disease (CKD) are often regarded as experiencing wasting of muscle mass and declining muscle strength and function, collectively termed sarcopenia. The extent of skeletal muscle wasting in clinical and preclinical CKD populations is unclear. We evaluated skeletal muscle atrophy in preclinical and clinical models of CKD, with multiple sub-analyses for muscle mass assessment methods, CKD severity, sex and across the different preclinical models of CKD. We performed a systematic literature review of clinical and preclinical studies that measured muscle mass/size using the following databases: Ovid Medline, Embase and Scopus. A random effects meta-analysis was utilized to determine standard mean difference (SMD; Hedges' g) between healthy and CKD. Heterogeneity was evaluated using the I2 statistic. Preclinical study quality was assessed via the Systematic Review Centre for Laboratory Animal Experimentation and clinical studies quality was assessed via the Newcastle-Ottawa Scale. This study was registered in PROSPERO (CRD42020180737) prior to initiation of the search. A total of 111 studies were included in this analysis using the following subgroups: 106 studies in the primary CKD analysis, 18 studies that accounted for diabetes and 7 kidney transplant studies. Significant atrophy was demonstrated in 78% of the preclinical studies and 49% of the clinical studies. The random effects model demonstrated a medium overall SMD (SMD = 0.58, 95% CI = 0.52-0.64) when combining clinical and preclinical studies, a medium SMD for the clinical population (SMD = 0.48, 95% CI = 0.42-0.55; all stages) and a large SMD for preclinical CKD (SMD = 0.95, 95% CI = 0.76-1.14). Further sub-analyses were performed based upon assessment methods, disease status and animal model. Muscle atrophy was reported in 49% of the clinical studies, paired with small mean differences. Preclinical studies reported significant atrophy in 78% of studies, with large mean differences. Across multiple clinical sub-analyses such as severity of CKD, dialysis modality and diabetes, a medium mean difference was found. Sub-analyses in both clinical and preclinical studies found a large mean difference for males and medium for females suggesting sex-specific implications. Muscle atrophy differences varied based upon assessment method for clinical and preclinical studies. Limitations in study design prevented conclusions to be made about the extent of muscle loss with disease progression, or the impact of dialysis. Future work would benefit from the use of standardized measurement methods and consistent clinical staging to improve our understanding of atrophy changes in CKD progression, and analysis of biological sex differences.

Sarcopenic Obesity Versus Nonobese Sarcopenia in Hemodialysis Patients: Differences in Nutritional Status, Quality of Life, and Clinical Outcomes

OBJECTIVE

Sarcopenia and sarcopenic obesity (SO) are linked to unfavorable prognosis in maintenance hemodialysis (MHD) populations. We tested whether nonobese sarcopenia and SO, as different stages of extreme protein-energy wasting, have different prognoses.

METHODS

In this prospective observational study, 261 MHD patients were recruited from October 2010 to April 2012 and followed until October 2020. Two definitions were used to diagnose sarcopenia: the European Working Group on Sarcopenia in Older People consensus and the Foundation for the National Institutes of Health (FNIH) Biomarkers Consortium criteria. Obesity was determined as the percentage of total body fat, ≥27% for men and ≥38% for women. Data for all-cause and cardiovascular morbidity and mortality, baseline nutrition markers, inflammation and oxidative stress, adipokines, body composition parameters, handgrip strength, and quality of life (QoL) scores were measured.

RESULTS

According to European Working Group on Sarcopenia in Older People, 115 (44.1%) patients were sarcopenic and 120 (46.0%) according to FNIH definitions. Of them, 28.4% and 34.5% were SO, respectively. Higher levels of albumin, creatinine, uric acid, leptin, phase angle, better nutritional scores, and lower adiponectin levels characterized SO patients compared with nonobese sarcopenic patients regardless of indexing method. Better QoL scores were noted in SO compared with nonobese sarcopenic patients using the FNIH sarcopenia criteria. The hazard of all-cause death, cardiovascular death, and first cardiovascular event for patients with SO was lower compared with the nonobese patients after multivariate adjustments. Statistical significance of these associations disappeared after including fat mass in multivariate models.

CONCLUSIONS

MHD patients with SO have better nutritional status and prognosis for cardiovascular events, all-cause and cardiovascular disease mortality, and possibly better QoL compared with nonobese sarcopenic MHD patients. The better prognosis appears to be entirely due to the excess fat, which is protective in sarcopenic MHD patients similar to that described in the entire MHD population.

The Relationship Between Nutritional Status Based on Subjective Global Assessment and Dialysis Adequacy

Background: Malnutrition is common in patients undergoing hemodialysis and leads to a decrease in dialysis adequacy. The evaluation of dialysis adequacy is very important. Objectives: This study was done to investigate the relationship between patients’ nutrition status based on Subjective Global Assessment (SGA) and their dialysis adequacy. Methods: This cross-sectional descriptive study was conducted in Tehran, Iran, in 2019. Three hundred qualified patients were selected by cluster sampling. Before the dialysis session, measurement of height and weight and blood sampling for albumin, total iron-binding capacity (TIBC), blood urea nitrogen (BUN), and creatinine (Cr) assessment were performed. After the dialysis session, measurement of weight and second sampling for BUN were done. SGA forms were filled by patients. Patients’ dialysis adequacy was calculated based on the DaugirdasII formula, and data were analyzed using SPSS 21. Results: From 300 patients, 128 cases (42.7%) had normal nutrition status, while 148 cases (49.3%) had mild to moderate malnutrition and 24 cases (8%) had severe malnutrition with mean dialysis adequacy of 1.07. The present study showed a significant statistical relationship between malnutrition and education (P < 0.001), body mass index (BMI) (P = 0.03), albumin (P < 0.001), TIBC (P < 0.001), and dialysis adequacy (P < 0.001). Gender, age, and dialysis duration showed no significant relationship with nutrition status based on the SGA index. Conclusions: The findings showed a high relative frequency of malnutrition and a decrease in patients’ dialysis adequacy, which emphasize the patient’s educational level, proper management of nutrition along with regular consultations by nutritionists, better implementation of the dialysis procedure, and regular follow-up of dialysis adequacy.

Long Pentraxin 3 as a Broader Biomarker for Multiple Risk Factors in End-Stage Renal Disease: Association with All-Cause Mortality

Persistent inflammation in end-stage renal disease (ESRD) patients is known to underlie the progression of chronic kidney disease and to be associated with multiple risk factors including malnutrition, atherosclerosis, and cardiovascular disease (CVD). The acute-phase protein pentraxin 3 (PTX3) has a proven potential as a local inflammatory biomarker, but its clinical utility in ESRD remains unclear. Circulating levels of PTX3 and classical inflammatory mediators, including the clinical prototypical C-reactive protein (CRP), were assessed in 246 ESRD patients on dialysis and analysed in relation to the lipid profile, adipokine levels, and nutritional, cardiac, and renal fibrosis markers. Occurrence of deaths was recorded for the following year. Contrarily to the classical inflammatory markers, PTX3 levels were negatively correlated with nutritional markers and associated with a less atherogenic lipid profile. Levels of the cardiac and renal fibrosis markers and of the oxidized LDL/LDL-C ratio were found to be independent determinants of PTX3 concentration. When comparing inflammatory mediators, the increase in the PTX3 levels was the only predictor of all-cause mortality in dialysis patients in a survival model adjusted to all markers under study, other than the inflammatory ones, besides common confounding factors in dialysis. Data support the clinical applicability of PTX3 as a broader inflammatory biomarker than the classical ones, presenting a close association with inflammation, malnutrition, CVD, and renal fibrosis and a great potential to predict all-cause mortality in dialysis patients. The pleiotropic character of PTX3 may be of clinical relevance, and it could be targeted to ameliorate the high morbidity and mortality associated with ESRD.

Physical activity increases the resistin concentration in hemodialyzed patients without metabolic syndrome

BACKGROUND

Resistin (RES) concentration increases in end-stage renal disease patients. However, there have been no studies defining the role of physical activity in RES concentrations in hemodialyzed (HD) patients. This study was aimed to determine metabolic and inflammatory effects, including RES, of 4-week supervised rehabilitation program in HD patients, with or without metabolic syndrome (MS).

METHODS

The study was completed by 28 patients aged 56.9±13.3 years ( x ¯ ± SD ) who were HD for 50.6±73.4 months, and 30 controls aged 61.5±8.3 years with normal renal function. Both the groups were divided into two subgroups with respect to MS. Individualized supervised rehabilitation program based on physiotherapy, including exercises, was provided to each subject for 4 weeks. Baseline and post-intervention complete blood count, glycated hemoglobin (HbA1c) and levels of serum RES, leptin, adiponectin, cystatin C, erythropoietin, high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), interleukin-6, transforming growth factor- β1, plasminogen activator inhibitor-1 homocysteine, insulin, albumin, parathyroid hormone (PTH), and phosphorus were measured.

RESULTS

Compared to controls, HD patients showed higher baseline leucocytes count and higher serum concentrations of RES, leptin, cystatin C, hs-CRP, TNF-α, homocysteine, phosphorus, PTH while hemoglobin, glucose, and albumin concentrations. A positive correlation between serum albumin and RES concentrations was observed in HD patients. Post-intervention RES increase was observed in HD patients without MS (post-intervention 34.22±8.89 vs baseline 30.16±11.04 ng/mL; P=0.046) while no change was observed in patients with MS and in the control group.

CONCLUSION

MS modifies a RES response to the rehabilitation program in HD patients.

Associations of Adiponectin, Leptin Levels, and the Change of Body Composition in Patients on Peritoneal Dialysis: A Prospective Cohort Study

Background

Although the association between adipokines such as adiponectin, leptin, and body composition has been noted, whether they could predict the change of fat mass and lean body mass is unknown. We aimed to examine these associations in patients on peritoneal dialysis (PD) through a prospective cohort study.

Methods

Body composition (by dual-energy x-ray absorptiometry) including fat mass and lean body mass were examined at baseline and then at year 3. Serum leptin and adiponectin levels were measured. Demographic data, comorbidity, biochemical data, inflammation (high-sensitive C-reactive protein [hs-CRP]) and insulin resistance (homeostatic model assessment [HOMA-IR]) were also examined.

Results

At baseline, serum adiponectin levels were significantly inversely correlated with weight, lean body mass index (LBMI), fat mass index (FMI), lean body mass (LBM), and fat mass (FM) in 213 prevalent patients. At year 3, FMI, LBMI, FM, and the percentage of FM (FM%) increased while the percentage of LBM (LBM%) significantly decreased despite unchanged weight and LBM among the remaining 112 patients. After adjustment for demographic data, comorbidities, hs-CRP, HOMA-IR, and daily energy intake (DEI), serum adiponectin at baseline was not associated with increases in LBMI, FMI, and FM, but independently associated with an increase in FM% and a decrease in LBM%. The predictive effect of high-serum adiponectin level on mortality disappeared after adjusting for diabetes and cardiovascular disease. Serum leptin was not associated with any changes in body composition during the follow-up, nor with the mortality in this cohort.

Conclusions

A high adiponectin level could predict an increase in FM% and a decrease in LBM% during a 3-year follow-up in PD patients. Serum adiponectin could not independently predict mortality in PD patients.

Associations of adiponectin and leptin levels with protein-energy wasting, in end stage renal disease patients

OBJECTIVE

The aim of the study was to examine the prevalence of protein-energy wasting (PEW) in hemodialysis (HD) and peritoneal dialysis (PD) patients in our center and determine whether adiponectin and leptin are involved in the development of PEW.

DESIGN

Prospective (18 months).

SETTING

University Hospital of Heraklion, Crete, Greece.

SUBJECTS

Seventy-four end-stage-renal-disease patients, 47 on HD and 27 on PD.

MAIN OUTCOME MEASURES

At three sequential time points (baseline, 6 and 18 months) anthropometric, nutritional and inflammatory status data were collected. Serum adiponectin and leptin were also assessed at each time point. Patients were allocated to 3 strata according to PEW severity (0, 1-2 and ≥3 criteria for PEW).

RESULTS

Adiponectin and leptin levels were greater among PD compared to HD patients (p≤0.035). Adiponectin levels were incrementally greater across increasing strata of PEW (p≤0.002). Leptin showed the opposite trend, with lower levels in malnourished patients and higher levels in patients with zero PEW criteria (p≤0.042). Alterations of adiponectin levels during the observation period were dependent on PEW stratum (p≤0.021) and mode of dialysis (p≤0.002), after adjustment for age, dialysis vintage, gender and fat mass index. Particularly, adiponectin levels increased over time in HD patients with ≥3 criteria for PEW, whereas adiponectin levels decreased in PD patients with ≥3 criteria for PEW throughout the study. Leptin alterations over time were not affected by dialysis mode or PEW stratification.

CONCLUSIONS

Our study provides evidence that increased adiponectin and decreased leptin levels are independently associated with PEW and thus, poor prognosis.

Comparison of malnutrition inflammation score, anthropometry and biochemical parameters in assessing the difference in protein-energy wasting between normal weight and obese patients undergoing haemodialysis

AIM

Protein-energy wasting (PEW) is prevalent in haemodialysis. Obesity is an independent risk factor of kidney insufficiency, but it is proposed to have beneficial roles in better outcomes in the final stage of disease. Better nutritional status and body reserves are among probable mechanisms, but direct examinations are limited. The present study aimed to investigate whether obese patients have preferable nutritional status compared to normal weight patients based on malnutrition inflammation score (MIS) and other PEW parameters in haemodialysis.

METHODS

This case-control study investigated 52 normal weight (18.5 < body mass index (BMI) < 25 kg/m² ) and 48 obese (BMI≥30 kg/m² ) patients on regular haemodialysis. PEW was assessed based on anthropometric and biochemical factors, recent weight changes, appetite, anorexia, dietary intake and MIS.

RESULTS

Obese patients had better MIS compared with the normal weight group (P < 0.001), although varying degrees of wasting were prevalent among this group too (75% mild and 25% moderate wasting). The obese group had less significant weight loss (4.2 vs 8%) and anorexia and better appetite. However, a considerable percentage of patients in both groups showed muscle (94.6% of normal weight and 19.5% of obese) and peripheral fat tissue (89.2% of normal weight and 31.7% of obese) losses compared to the 50th percentile. Biochemical parameters were not significantly different between groups except for triglyceride (P = 0.001), transferrin and total iron-binding capacity (P = 0.028).

CONCLUSIONS

MIS was significantly better in obese patients; however, both groups showed degrees of wasting based on MIS and other PEW parameters. Nutritional status of obese haemodialysis patients should be monitored regularly because of high risk of PEW like other BMI categories.

Sensitivity and Specificity of Body Mass Index as a Marker of Obesity in Elderly Patients on Hemodialysis

OBJECTIVES

Diagnosing obesity by body mass index (BMI) may not be reliable in elderly individuals due to the changes in body composition. We aimed to analyze the accuracy of BMI thresholds by World Health Organization (WHO) and Nutrition Screening Initiative (NSI) to diagnose obesity in elderly patients on hemodialysis (HD).

DESIGN

Multicenter cross-sectional study.

SETTING

Six dialysis facilities.

SUBJECTS

169 elderly on chronic HD (70.4 ± 7.1 years; 63.9% men).

MAIN OUTCOME VARIABLE

Total body fat percentage (BF%) was assessed by the sum of skinfold thicknesses and abdominal fat by waist circumference (WC). Both were used as reference to test the specificity and sensitivity of BMI thresholds (WHO: ≥30 kg/m(2); NSI: >27 kg/m(2)).

RESULTS

The prevalence of obesity according to NSI-BMI, WHO-BMI, BF%, and WC thresholds were 31%, 13%, 27%, and 29.6% in men, respectively, and 36%, 15%, 13%, and 75% in women. Compared to BF%, the sensitivity of NSI-BMI was moderate (65.5%) for men and high (100%) for women, whereas that of WHO-BMI was low (31%) for men and high (87.5%) for women. Compared with WC, NSI-BMI had good (75%) sensitivity for men and moderate (47.8%) for women, whereas WHO-BMI had moderate (43.8%) sensitivity for men and low (19.6%) for women. The best agreement with BF% was observed for NSI-BMI in men (kappa = 0.46) and for WHO-BMI in women (kappa = 0.80). For WC, the best agreement was for WHO-BMI for men (kappa = 0.63) and NSI-BMI for women (kappa = 0.31).

CONCLUSIONS

BMI thresholds do not accurately diagnose adiposity in elderly on HD. Therefore, using BMI may lead to misclassifications in this segment population.

The Effect of BCAA and ISO-WHEY Oral Nutritional Supplements on Dialysis Adequacy

Background

Protein-energy malnutrition is a common problem in hemodialysis patients and has different outcomes such as reduced quality of life, longer hospitalization time, lower dialysis adequacy, and higher mortality rate. Investigation of dialysis adequacy is an important method for assessing hemodialysis patients, and improving the dialysis adequacy is an important healthcare team goal.

Objectives

The present study aims to investigate and compare the effects of BCAA and ISO-WHEY oral nutritional supplements on dialysis adequacy.

Methods

In a clinical trial study, 66 hemodialysis patients were randomly divided into three groups: Group A (n = 22), Group B (n = 22), and Group C or the control group (n = 22). In Groups A and B, as prescribed and controlled by nutritionists and nephrologists, respectively, ISO-WHEY and BCAA protein powder were used for 2 months on a daily basis. For all groups, before intervention and 1 and 2 months after intervention, the dialysis adequacy was measured using URR and Kt/V. Finally, the data were analyzed using IBM SPSS Statistics Base 21.0 software.

Results

Out of 66 patients, 61 (19 in Group A, 20 in Group B, and 22 in Group C) completed the study period, and before intervention, all groups were equal in terms of quality and quantity variables (P > 0.05). After intervention, there was a significant difference between the three groups with regard to the variables of dialysis adequacy based on Kt/V and URR to independent-t test and repeated measures ANOVA (P < 0.05).

Conclusions

Results show that the intake of oral nutritional supplements leads to an improvement in the dialysis adequacy of hemodialysis patients. Therefore, the use of nutritional supplements along with patients' training and regular consultation will be helpful in improving the nutritional status, dialysis adequacy, and eventually the quality of life.

Elevated resistin levels are associated with inflammation in hemodialysis patients with failed renal allografts

BACKGROUND

Resistin is an adipocytokine, associated with insulin resistance and inflammation. The aim of this study is to evaluate the levels of serum resistin levels and other markers of inflammation in hemodialysis (HD) patients with failed renal allografts.

METHODS

Sixty-nine HD patients with failed renal allografts and 98 never transplanted (naive) HD patients and also 21 healthy controls were included in the study. Serum levels of various biochemical parameters as well as resistin, IL-6, TNF-α and hs-CRP as biochemical markers of inflammation, were measured.

RESULTS

Serum resistin levels in patients with failed renal allografts (4.80 ± 2.06 ng/mL) were significantly higher than those of the naive HD patients (3.44 ± 1.48 ng/mL) and healthy controls (0.95 ± 0.38 ng/mL; p<0.001). Patients with failed transplants were also characterized by higher TNF-alpha levels (96.8 ± 131.3 pg/mL vs. 40.9 ± 25.4 pg/mL; p<0.001) and IL-6 levels (83.9 ± 150.9 pg/mL vs. 14.6 ± 14.4 pg/mL; p<0.001) as compared to naive HD patients. Serum hs-CRP levels in patients with failed renal allografts (9.33 ± 11.86 mg/L) were significantly higher than those of the naive HD patients (1.26 ± 1.71 mg/L) and healthy controls (2.12 ± 1.82 mg/L; p<0.001). Serum albumin levels in patients with failed transplants (3.84 ± 0.47 g/dL) were lower as compared to never transplanted HD patients (4.13 ± 0.33 g/dL) and healthy controls (4.53 ± 0.40 g/dL; p<0.001). There was a positive correlation between serum resistin and TNF-alpha levels (r = 0.486, p<0.001).

CONCLUSIONS

Serum resistin levels are increased in HD patients with failed renal allografts very probably reflecting an allograft-induced chronic inflammatory state.

Validation of Mini Nutritional Assessment Scale in peritoneal dialysis patients

INTRODUCTION

Malnutrition is a negative predictive factor for survival in end stage renal disease (ESRD) patients. Coincidence of malnutrition, inflammation and atherosclerosis (MIA syndrome) in the dialysis population is an exceptionally poor outcome event. Due to flexibility, ease of performance and reproducibility, clinical scales are of particular value in assessment of nutritional status in ESRD patients. The aim of the present study was to evaluate the clinical value of Mini Nutritional Assessment (MNA) in peritoneal dialysis (PD) patients.

MATERIAL AND METHODS

Nutritional status was assessed in 41 peritoneal dialysis patients by means of the MNA scale and malnutrition inflammation score (MIS). Some other clinical and laboratory parameters associated with nutritional status were analyzed. Patients were followed up for 30 months.

RESULTS

In the analyzed group of patients a good nutritional state was diagnosed in 22 patients (54%), risk of malnutrition in 17 (41%) and malnutrition in 2 patients (5%) based on the MNA scale. A strong correlation between MNA based nutritional status and MIS was found (r = -0.85, p < 0.01, ANOVA, p < 0.01). Differences in time on dialysis, body mass index, concentration of albumin, cholesterol and triglycerides were noted between at risk/malnourished and well-nourished (according to MNA) patients. Statistically significant factors determining survival of patients by Cox proportional hazard analysis were age (HR 1.07), being at risk/malnourished according to MNA (HR 5.7), MIS (HR 1.2), and albumin (HR 0.13).

CONCLUSIONS

The MNA scale is a valuable, clinically suitable tool for assessment of nutritional status in peritoneal dialysis patients. Risk of malnutrition and malnutrition diagnosed by MNA identifies patients at high mortality risk.

Relationship between zinc levels and plasma leptin in hemodialysis patients

Recent evidences suggested a possible relationship between zinc deficiency and leptin levels in pathogenesis of anorexia in chronic kidney disease. The present study addressed the relationship between zinc and leptin in hemodialysis (HD) patients.

METHODS

Fifty HD patients (54.3±12.7years old, 62% men) were studied and compared to 21 healthy volunteers (50.7±15.7years old, 43% men). Biochemical data, serum zinc, plasma leptin, IL-6, TNF-α and C-Reactive Protein levels were determined. Anthropometric parameters, food intake and appetite score were also assessed.

RESULTS

The leptin levels were higher in HD patients (16.1μg/mL (0.21-118.25) vs 6.0μg/mL (0.50-23.10)) in healthy volunteers (p=0.04), whereas serum zinc levels were lower (54.5±16.3μg/dL) compared to healthy volunteers (78.4±9.4μg/dL) (p=0.0001). The plasma leptin was correlated negatively with plasma zinc (r=-0.33; p=0.007), energy (r=-0.38; p=0.002) and protein intake (r=-0.34; p=0.006) and, positively correlated with BMI (r=0.54; p=0.0001), % body fat (r=0.70; p=0.0001) and conicity index (r=0.46; p=0.001). Plasma zinc was associated with hemoglobin (r=0.30; p=0.04) and negatively associated with TNF-α (r=-0.37; p=0.002) and C-Reactive Protein (r=-0.37; p=0.004). There was no correlation among Zn, leptin and appetite score in these patients.

CONCLUSION

This study showed that low plasma zinc levels are negatively associated with high leptin levels in HD patients.

Low resistin level is associated with poor hospitalization-free survival in hemodialysis patients

Malnutrition and inflammation are related to high rates of morbidity and mortality in hemodialysis patients. Resistin is associated with nutrition and inflammation. We attempted to determine whether resistin levels may predict clinical outcomes in hemodialysis patients. We conducted a prospective evaluation of 100 outpatients on hemodialysis in a single dialysis center (male, 46%; mean age, 53.7 ± 16.4 yr). We stratified the patients into 4 groups according to quartiles of serum resistin levels. During the 18-month observational period, patients with the lowest quartile of serum resistin levels had poor hospitalization-free survival (log rank test, P = 0.016). After adjustment of all co-variables, patients with the lowest quartile of serum resistin levels had poor hospitalization-free survival, compared with reference resistin levels. Higher levels of interleukin-6 were an independent predictor of poor hospitalization-free survival. In contrast, serum resistin levels were not correlated with interleukin-6 levels. The current data showed that low resistin levels may independently predict poor hospitalization free survival in hemodialysis patients.