Outcomes associated with intradialytic oral nutritional supplements in patients undergoing maintenance hemodialysis: a quality improvement report

A roadmap for implementing a successful clinical experience with intradialytic parenteral nutrition

BACKGROUND AND AIMS

Intradialytic parenteral nutrition (IDPN) is a safe and effective patient-tailored nutritional strategy for providing nutrient supplementation to malnourished or at risk of malnutrition patients on hemodialysis (HD), who did not adequately respond to intensive dietary counselling and oral nutritional supplementation. Although IDPN is recommended by current ESPEN and KDOQI guidelines for nutrition in HD patients, none of these documents informs how to successfully implement this therapy, being the lack of knowledge on practical aspects of IDPN one of the main limitations to its use. The aim of this narrative review was to provide a practical roadmap for guiding the nephrologists, dietitians, and renal nurses in their everyday clinical practice about the use of IDPN.

METHODS

A multidisciplinary group formed by specialists from the areas of Nephrology and Nutrition agreed to address different practical aspects related to IDPN in HD patients. Based on the available evidence in the literature and on the authors' clinical experience, different topics were selected to develop a detailed plan for implementing a successful experience with IDPN, proposing a practical IDPN roadmap.

RESULTS

This IDPN roadmap provides practical information on when an IDPN should be started; what type of nutrients should be part of an IDPN; how the IDPN should be administered; how the effectiveness and safety of the IDPN should be monitored; how to determine the effectiveness of IDPN; and the conditions that advise discontinuing the IDPN.

CONCLUSIONS

IDPN is a safe and effective nutritional therapy for HD patients, although the lack of staff training may limit its use. This review addresses different practical aspects of IDPN, helping interdisciplinary teams in their daily clinical practice to improve the nutritional care of HD patients, either malnourished or at risk of malnutrition.

Change Over Time in Pre-End-Stage Renal Disease 24-Hour Urine Creatinine as Muscle Mass Surrogate and Post-End-Stage Renal Disease Mortality

OBJECTIVE

Loss of muscle mass and sarcopenia are common in chronic kidney disease (CKD) and end-stage renal disease (ESRD), and sarcopenia can worsen insidiously in patients with advancing CKD. The temporal dynamics of sarcopenia in patients with progressive loss of kidney function, and its association with future outcomes, is unclear.

METHODS

In a contemporary national cohort of incident ESRD US veterans, we selected 661 patients who had at least 2 24-hour urine creatinine (24hrUC) measurements, a surrogate of muscle mass, performed during the 3-year prelude period prior to ESRD transition. We estimated 24hrUC slopes in mixed effects models. To assess the temporal dynamics of pre-ESRD changes in 24hrUC and its association with changing eGFR, we separately fitted in mixed effects models a penalized spline regression of 24hrUC on time and on eGFR. We examined the association of 24hrUC slopes with postdialysis all-cause mortality using Cox models adjusted for confounders.

RESULTS

The mean slope of 24hrUC versus time was -78 mg/year (95% confidence interval: -102 to -54), with a steeper decline noted in the last year prior to ESRD. More severe decreases in 24hrUC were associated with higher all-cause mortality: a 100 mg/year decrease in 24hrUC was associated with a multivariable adjusted death hazard ratio of 1.41 (95% confidence interval: 1.00-1.98, P = .05).

CONCLUSION

Patients with advanced CKD lose a substantial proportion of their muscle mass each year during pre-ESRD prelude. Loss of muscle mass accelerates near ESRD transition, and more loss of muscle mass is associated with higher mortality after ESRD transition.

Is intradialytic oral nutritional supplementation safe and effective on clinical outcomes? A systematic review with conventional meta-analysis and network meta-analysis

AIM

determine the effect of intradialytic oral nutrition (ION) on clinical and safety outcomes.

DESIGN

Systematic Review with conventional Meta-analysis, and a Network Meta-analysis (NMA) as sensitivity analysis. We searched on MEDLINE, LILACS, CENTRAL, and EMBASE in June 2020, and the last update was until August 2022. We selected observational and randomized controlled trials with ION for at least four weeks. Primary outcomes were all-cause mortality and quality of life (QoL); adverse events, physical performance, and appetite were secondary outcomes.

RESULTS

Seven clinical trials and three observational studies were selected. Even when we did not obtain significant differences in physical performance and gastrointestinal symptoms, we identified a clinical improvement in the QoL's physical role, bodily pain, and physical performance domains. After pooling the data on mortality, a protection rate trend was observed in the ION group without statistical significance. The home-prepared ION was the best nutritional supplementation when assessing the appetite outcome through NMA.

CONCLUSIONS

ION seems to have a protective trend in mortality risk; the current evidence is insufficient to establish a relationship with adverse events or other clinical outcomes. The lack of homogeneity in the trials makes it difficult to generalize these results.

PROSPERO REGISTRATION

CRD42020186311.

Effects of nutritional supplementation stabilizing muscle mass loss in older patients on hemodiafiltration

BACKGROUND & AIMS

Malnutrition is common in older individuals with end-stage renal disease on maintenance dialysis. Whether nutritional supplementation may improve skeletal muscle mass (SMM) and survival rate in this population is uncertain. We aimed to analyze the effect of a year of nutritional supplementation on muscle mass and survival rate in older patients on hemodiafiltration.

METHODS

In this observational study, older patients (≥65 years old) on maintenance hemodiafiltration were selected to receive nutritional counselling + nutritional supplementation (N = 85, Supp+) or nutritional counselling alone (N = 47, Supp-) and followed for 1 year. The outcomes were a change in SMM and sarcopenia diagnosis. The secondary outcome was 1-year mortality rate. Nutritional parameters included calf circumference, body mass index, anthropometric measurements, subjective global assessment, and handgrip strength (HGS). Data were evaluated using GLM for repeated measures with adjustment for covariates (age and diabetes).

RESULTS

Malnutrition was found in 50.8% of patients. At baseline, patients from the Supp+ group were older and had worse nutritional parameters including hand grip strength, calf circumference, anthropometric findings and sarcopenia (all p values < 0.05). During the follow-up, there was no significant change in sarcopenia (from 50.8% to 58.3%, p = 0.108), and there was a more pronounced decrease in the SMM index in the Supp-group (p = 0.049), with a significant intervention interaction (p = 0.030). Twenty deaths occurred, 7 (35%) in the Supp- and 13 (65%) in the Supp+ group (p = 0.540). SMM index (relative risk 0.90, p = 0.030) and age (relative risk 1.07, p = 0.046) were independently associated with higher mortality rates.

CONCLUSION

Nutritional supplementation in older and malnourished individuals undergoing hemodiafiltration mitigates the loss of the SMM index and benefits survival rate.

Effects of oral nutritional supplements on the nutritional status and inflammatory markers in patients on maintenance dialysis: a systematic review and meta-analysis of randomized clinical trials

Background and aims

Patients on hemodialysis (HD) or peritoneal dialysis (PD) often have insufficient energy and protein intake, resulting in poor nutritional status and adverse outcomes. Oral nutritional supplements (ONSs) are the most commonly used to increase such patients' energy and protein intakes.

Methods

In this systematic review and meta-analysis, we analyzed studies on nutritional status, inflammatory markers, and electrolyte levels in patients on dialysis receiving ONSs. We searched four electronic databases from inception until 31 December 2022, for randomized controlled trials comparing ONS treatment versus placebo or routine care.

Results

22 studies with 1185 patients on dialysis were included in our meta-analysis. Compared with the control group, the ONS group exhibited significantly increased serum albumin levels [1.26 g/l (95%CI, 0.50-2.02, P < 0.0001; I2 = 80.4%)], body mass indexes (BMIs) [0.30 kg/m2 (95%CI, 0.09-0.52, P = 0.005; I2 = 41.4%)], and handgrip strength (HGS) [0.96 kg (95%CI, 0.07-1.84, P = 0.034; I2 = 41.4%)] from baseline to the end of intervention. No significant differences were observed between the groups in lean body mass, phase angle, C-reactive protein, and serum phosphorus and potassium levels. In terms of improving albumin, the subgroup analyses show that ONS use seems to be more inclined to three variations: HD patients, short-term use, and non-intradialytic supplementation.

Conclusion

In conclusion, ONS use can improve the nutritional status of patients on dialysis in terms of their serum albumin, BMI, and HGS without significant effects on serum phosphorus, potassium, and C-reactive protein levels. However, it remains uncertain whether these results translate to improvement in clinically relevant outcomes. Large-scale high-quality studies are still required in this population.

[Unintentional weight loss in chronic kidney disease]

If the causes of unintended weight loss are already diverse in pre-dialysis patients, at the stage of dialysis requirement a variety of other causes are added. Both stages share a trend towards loss of appetite and nausea, whereby uremic toxins certainly do not represent the only cause. In addition, both stages involve increased catabolism and therefore a higher calorie requirement. In the dialysis stage, protein loss (more in peritoneal dialysis than in hemodialysis) and the sometimes extensive dietary restrictions (low potassium, low phosphate, fluid restriction) are added. The problem of malnutrition, especially in dialysis patients, has been increasingly recognized in recent years, and there is a trend towards improvement. Initially, the causes of weight loss were subsumed under the terms protein energy wasting (PEW), which emphasized the protein loss in dialysis, and malnutrition-inflammation-atherosclerosis (MIA) syndrome, which highlighted chronic inflammation in dialysis patients; however, a variety of other factors contribute to weight loss, which are better described by the term chronic disease-related malnutrition (C-DRM). Weight loss is the most significant factor in recognizing malnutrition, as pre-existing obesity (especially type II diabetes mellitus) often makes the recognition more difficult. In the future, the increasing use of glucagon-like peptide 1 (GLP-1) agonists for weight loss could also lead to weight loss being perceived as intentional rather than distinguishing between intentional fat loss and unintentional loss of muscle mass.

Effect of intradialytic oral nutritional supplementation on nutritional markers in malnourished chronic hemodialysis patients: prospective randomized trial

BACKGROUND AND OBJECTIVES

Malnutrition is prevalent in chronic hemodialysis (HD) patients. It increases mortality and negatively affects quality of life. This study aimed to assess the effect of intradialytic oral nutritional supplement (ONS) on nutritional markers in chronic HD patients with protein energy wasting (PEW).

METHODS

This 3-month prospective, open-label, randomized controlled trial included 60 chronic HD patients with PEW. The intervention group (30 patients) received intradialytic ONS and dietary counseling, whereas the control group (30 patients) received only dietary counseling. Nutritional markers were measured at the beginning and end of the study.

RESULTS

The mean age of the patients was 54 ± 12.7 years, and that of the HD vintage was 64 ± 49.3 months. Compared to the control group, the intervention group showed a significant increase in serum albumin (p < 0.001), prealbumin (p < 0.001), cholesterol (p = 0.016), body mass index (BMI) (p = 0.019), serum creatinine/body surface area (BSA) (p = 0.016), and composite French PEW score (p = 0.002), as well as a significant decrease in high-sensitivity C-reactive protein (hs-CRP) (p = 0.001). The total iron binding capacity, normalized protein nitrogen appearance, and hemoglobin levels increased significantly in both groups.

CONCLUSION

Intradialytic ONS and dietary counseling for three months were more effective than dietary counseling alone in terms of improving nutritional status and inflammation in chronic HD patients, as evidenced by increases in serum albumin, prealbumin, BMI, serum creatinine/BSA, composite French PEW score, and a decrease in hs-CRP.

Effect on nutritional status and biomarkers of inflammation and oxidation of an oral nutritional supplement (with or without probiotics) in malnourished hemodialysis patients. A multicenter randomized clinical trial "Renacare Trial"

Background

Malnutrition in patients undergoing hemodialysis is frequent and associated with a reduction in muscular mass and strength, with an increment in biomarkers of inflammation and oxidation.

Materials and methods

Randomized, multicenter, parallel-group trial in malnourished hemodialysis patients with three groups [(1) control (C) individualized diet, (2) oral nutritional supplement-ONS- + placebo-SU- PL-, and (3) ONS + probiotics-SU-PR]; the trial was open regarding the intake of ONS or individualized diet recommendations, but double-blind for the intake of probiotics. We obtained, at baseline and after 3 and 6 months, anthropometric measurements, handgrip strength, bioelectrical impedance analysis (BIA), dietary records, and routine biochemical parameters. Inflammation and oxidation were determined using ELISA techniques (Versamax and ProcartaPlex multiplex Immunoassay). Results were analyzed by intention to treat.

Results

A total of 31 patients (11 corresponding to group C, 10 to SU-PL, and 10 to SU-PR) completed the 6-months trial. The two groups that took supplements significantly increased their protein calorie, fat (total and n-3), and fiber intake. Weight and fat-free mass (FFM) also increased significantly in the groups on supplements, both at 3 and 6 months, and dynamometry did so in the SU-PL group. At month 3, prealbumin and vitamin D were significantly increased in the SU-TOT (SU-PL + SU-PR) group. No changes were observed regarding levels of phosphorus and potassium in any of the groups. Urea increased significantly at 6 months in the SU-PL group. There were significant changes in some inflammation biomarkers in the groups on supplements during the intervention (brain-derived neurotrophic factor, bone morphogenetic protein-2, MCP-1, IL-1-beta, IL-10, IL-4, and IL-8). The total antioxidant capacity (TAC) increased significantly in the supplemented patients, with no significant changes observed in isoprostanes.

Conclusion

The specific ONS improved protein-calorie intake, nutritional status (mainly FFM), and some biomarkers of inflammation/oxidation. The addition of probiotics could have a synergistic effect with ONS in such biomarkers.

Clinical trail registration

https://clinicaltrials.gov/ct2/show/, identifier NCT03924089.

Impact of Geriatric Nutritional Risk Index and Modified Creatinine Index Combination on Mortality in Hemodialysis Patients

The prognostic impact of the combination of a geriatric nutritional risk index (GRNI) and modified creatinine index, both of which assess nutritious status in hemodialysis patients, has not yet been well investigated thus far. Patients receiving maintenance hemodialysis in our institutes between February 2011 and January 2017 were retrospectively included. The baseline GRNI and modified Creatinine index were calculated and the impact of their combination on 5-year all-cause mortality following the index hemodialysis was investigated. A total of 183 patients (68.3 ± 12.4 years, 98 men, hemodialysis duration 97 ± 89 months) were followed from the index hemodialysis for 5.5 years. Mean GNRI was 91.2 and mean modified Creatinine index was 22.2 in men and 19.6 in women. The 5-year survival was significantly stratified by the median values of GNRI and modified Creatinine index (p < 0.05 for both). Patients with low GNRI and a low modified Creatinine index had lower 5-year survival than those with the other three combination patterns (p < 0.05). A combination of GNRI and modified Creatinine index may be a promising tool to risk stratify mortality in dialysis patients.

Avenues for post-translational protein modification prevention and therapy

Non-enzymatic post-translational modifications (nPTMs) of proteins have emerged as novel risk factors for the genesis and progression of various diseases. We now have a variety of experimental and established therapeutic strategies to target harmful nPTMs and potentially improve clinical outcomes. Protein carbamylation and glycation are two common and representative nPTMs that have gained considerable attention lately as favorable therapeutic targets with emerging clinical evidence. Protein carbamylation is associated with the occurrence of cardiovascular disease (CVD) and mortality in patients with chronic kidney disease (CKD); and advanced glycation end products (AGEs), a heterogeneous group of molecules produced in a series of glycation reactions, have been linked to various diabetic complications. Therefore, reducing the burden of protein carbamylation and AGEs is an appealing and promising therapeutic approach. This review chapter summarizes potential anti-nPTM therapy options in CKD, CVD, and diabetes along with clinical implications. Using two prime examples-protein carbamylation and AGEs-we discuss the varied preventative and therapeutic options to mitigate these pathologic nPTMs in detail. We provide in-depth case studies on carbamylation in the setting of kidney disease and AGEs in metabolic disorders, with an emphasis on the relevance to reducing adverse clinical outcomes such as CKD progression, cardiovascular events, and mortality. Overall, whether specific efforts to lower carbamylation and AGE burden will yield definitive clinical improvement in humans remains largely to be seen. However, the scientific rationale for such pursuits is demonstrated herein.

Trajectories of Nutritional Parameters Before and After Prescribed Oral Nutritional Supplements: A Longitudinal Cohort Study of Patients With Chronic Kidney Disease Not Requiring Dialysis

Background:

The association between oral nutritional supplement use and nutritional parameters among patients with nondialysis chronic kidney disease (CKD-ND) with or at high risk of undernutrition/protein-energy wasting has not been previously studied. The definition of patient subgroups most likely to benefit from oral nutritional supplementation (ONS) is also an area where more research is needed.

Objective:

To assess nutritional parameter trajectories among patients with CKD-ND prescribed oral nutritional supplements in British Columbia, and to compare trajectories by nutritional phenotype.

Design:

Longitudinal cohort study, pre-post design.

Setting:

Multidisciplinary CKD clinics across British Columbia.

Patients:

A total of 3957 adult patients with CKD-ND, who entered multidisciplinary CKD clinics during 2010 to 2019, met criteria for oral nutritional supplement prescription based on dietitian assessment, and received ≥1 oral nutritional supplement prescription.

Measurements:

Longitudinal nutritional parameters, including body mass index (BMI), serum albumin, serum bicarbonate, serum phosphate, and neutrophil-to-lymphocyte ratio (NLR).

Methods:

Using linear mixed models, slopes for nutritional and inflammation parameters were assessed in the 2-year periods before and after the first oral nutritional supplement prescription. Hierarchical cluster analysis was applied to identify nutritional phenotypes using baseline data, and slope analysis was repeated by cluster.

Results:

In the pre-oral-nutritional-supplement period, declines in BMI (−0.87 kg/m2/year, 95% confidence interval [CI]: −0.99 to −0.75), albumin (−1.11 g/L/year, 95% CI: −1.27 to −0.95), and bicarbonate (−0.49 mmol/L/year; 95% CI: −0.59 to −0.39), and increases in NLR (+0.79/year; 95% CI: 0.60 to 0.98) and phosphate (+0.05 mmol/L/year; 95% CI: 0.04 to 0.06) were observed. Following oral nutritional supplement prescription, there were statistically significant increases in BMI slope (+0.91 kg/m2/year, P < .0001), albumin slope (+0.82 g/L/year, P < .0001), and phosphate slope (+0.02 mmol/L/year, P = .005), as well as a decline in NLR slope of −0.55/year ( P < .0001). There was no significant change in bicarbonate slope. Cluster analysis identified 5 distinct phenotypes. The cluster with the highest mean baseline NLR and lowest mean BMI demonstrated the greatest number of improvements in nutritional parameter slopes in the post-oral-nutritional-supplement period.

Limitations:

Possibility of residual confounding. Data on dietary intake, muscle mass, and nutritional scoring systems were not available in the registry.

Conclusions:

Among patients with CKD-ND prescribed oral nutritional supplements, there were improvements in nutrition/inflammation parameters over time following the first ONS prescription. The heterogeneity in response to ONS by cluster subgroup suggests an individualized approach to nutritional management may be beneficial.

Nutritional Status, Nutritional Phenotypes, and Oral Nutritional Supplement Prescription Patterns Among Patients With Non-Dialysis Chronic Kidney Disease in British Columbia

OBJECTIVES

Management of protein-energy wasting and undernutrition with oral nutritional supplements (ONS) has not been systematically studied in the non-dialysis chronic kidney disease (CKD-ND) population. We aimed to describe nutritional status, identify phenotypes of patients prescribed ONS, and evaluate ONS prescription patterns among CKD-ND patients in British Columbia.

DESIGN AND METHODS

This observational study assessed adult CKD-ND patients who entered multidisciplinary CKD clinics during 2013-2018 in British Columbia. Descriptive statistics were used to describe baseline nutrition and inflammation parameters among patients prescribed ONS versus patients not prescribed ONS within 1 year of clinic entry. Hierarchical clustering method with consensus clustering was applied to identify phenotypes of patients prescribed ONS. Multivariable logistic regression was used to assess the associations between ONS prescription and health region/dietitian full-time equivalents per 1,000 CKD patients.

RESULTS

Of 15,859 CKD-ND patients, 9% of patients entering CKD clinics were prescribed ONS within 1 year of clinic entry, and these patients demonstrated lower baseline estimated glomerular filtration rate, body mass index (BMI), serum albumin, bicarbonate, as well as greater age, serum phosphate, and neutrophil-to-lymphocyte ratio compared with those not receiving ONS. Cluster analysis revealed 5 phenotypes of ONS users: cluster 1 had the highest mean neutrophil-to-lymphocyte ratio; cluster 2 had the lowest mean albumin; cluster 3 had the lowest mean BMI; cluster 4 had the highest mean BMI; and cluster 5 had the lowest mean bicarbonate. There was regional variability in ONS prescription, and an odds ratio for ONS prescription of 1.32 (95% confidence interval 1.16-1.50) for every 1-unit increase in dietitian full-time equivalents per 1,000 patients. Over 3 years of follow-up, overall ONS use among CKD-ND patients remained stable.

CONCLUSIONS

This study demonstrates appropriate prescribing of ONS to patients with suboptimal nutritional status, although regional variation exists. Patients receiving ONS represent a heterogenous group with phenotypes reflecting several clinical and biochemical features of the protein-energy wasting syndrome. These findings will assist with updating ONS policy, planning quality improvement initiatives, and informing dietitian resource allocation.

Intradialytic nutrition and quality of life in Chilean older patients in hemodialysis with protein-energy wasting

PURPOSE

The study assessed the impact of intradialytic oral nutritional supplementation on the quality of life in patients receiving hemodialysis and diagnosed with protein energy wasting.

METHODS

A pre-test post-test quasi-experimental study was conducted before and after 3 months of intradialytic oral nutritional supplementation on 109 older hemodialysis patients. We measured before and after 3 months of intradialytic oral nutritional supplementation, the quality of life score, the burden of kidney disease, three quality of life scales and the mental and physical health status using KDQoL-SF™ 1.3, body composition and biochemical parameters of nutritional condition.

RESULTS

The mean age of the patients was 69.4 ± 3.4 years, 59% were male, and the time on dialysis was 63.5 ± 52.6 months. Comparing the baseline with month 3 of intradialytic oral nutritional supplementation, we observed to better quality of life. In contrast to malnutrition, score, specifically increased significantly score of symptoms/problems list related to hemodialysis, sexual function, social and cognitive function, sleep, pain, energy/fatigue and general state of health. Significant changes were also found in nutritional status, energy intake and body composition indicators. After 3 months of intradialytic oral nutritional supplementation, we observed a nutritional status recovery in one or more indicators in 92% of the patients.

CONCLUSION

Our findings indicate that 3 months of intradialysis oral nutritional supplementation improves the components of physical and mental quality of life and nutritional status in older patients receiving hemodialysis diagnosed with loss of protein energy. These results are relevant to improve the experience of patients with protein energy loss receiving hemodialysis.

Importance of Considering Malnutrition and Sarcopenia in Order to Improve the QOL of Elderly Hemodialysis Patients in Japan in the Era of 100-Year Life

In the current aging society of Japan, malnutrition and resultant sarcopenia have been widely identified as important symptomatic indicators of ill health and can cause impairments of longevity and quality of life in older individuals. Elderly individuals are recommended to have sufficient calorie and protein intake so as to enjoy a satisfactory quality of life, including maintaining activities of daily living in order to avoid emaciation and sarcopenia. The prevalence of emaciation and sarcopenia in elderly hemodialysis (HD) patients in Japan is higher than in non-HD elderly subjects due to the presence of malnutrition and sarcopenia associated with chronic kidney disease (CKD). Furthermore, comorbidities, such as diabetes and osteoporosis, induce malnutrition and sarcopenia in HD patients. This review presents findings regarding the mechanisms of the development of these early symptomatic conditions and their significance for impaired QOL and increased mortality in elderly HD patients.

Efficacy of intradialytic amino acids on nutritional status in children with stage 5 chronic kidney disease

BACKGROUND

Protein energy wasting (PEW) is a common cause of morbidity and mortality in patients with stage 5 chronic kidney disease (CKD 5). Intradialytic parenteral nutrition (IDPN) has been used as a therapy for preventing and treating PEW in children with CKD 5 when other conventional modalities fail. However, not enough data is available to define its effectiveness in treating malnutrition in children. This study aims to investigate potential benefits of IDPN in Egyptian children with CKD 5.

METHODS

In this prospective, placebo-controlled, parallel-group single blinded study, we enrolled 50 CKD 5 patients; 25 patients (intervention group) received intravenous amino acids (KIDIMN), while 25 patients (control group) received normal saline as placebo, each given during regular dialysis 3 times a week for 9 months. Patients were subjected to nutritional assessment at baseline and 3-, 6-, and 9-month follow-up using height Z-score, hand grip strength (HGS) for muscle power assessment, body composition monitor (BCM) for assessing lean tissue mass (LTM) and adipose tissue mass (ATM), and biochemical measures including serum albumin, serum triglyceride, and serum cholesterol.

RESULTS

When comparing baseline and 9-month follow-up values, significant improvement was recorded in height Z-score, LTM, and serum albumin in the intervention group unlike the control group where no significant changes were recorded.

CONCLUSION

IDPN is proposed to be an effective method for preventing and treating malnutrition in children with CKD 5. However, further multi-centric studies with larger sample size and longer duration of follow-up are still recommended.

Significance of Adipose Tissue Maintenance in Patients Undergoing Hemodialysis

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

Anabolic Resistance of Muscle Protein Turnover Comes in Various Shapes and Sizes

Anabolic resistance is defined by a blunted stimulation of muscle protein synthesis rates (MPS) to common anabolic stimuli in skeletal muscle tissue such as dietary protein and exercise. Generally, MPS is the target of most exercise and feeding interventions as muscle protein breakdown rates seem to be less responsive to these stimuli. Ultimately, the blunted responsiveness of MPS to dietary protein and exercise underpins the loss of the amount and quality of skeletal muscle mass leading to decrements in physical performance in these populations. The increase of both habitual physical activity (including structured exercise that targets general fitness characteristics) and protein dense food ingestion are frontline strategies utilized to support muscle mass, performance, and health. In this paper, we discuss anabolic resistance as a common denominator underpinning muscle mass loss with aging, obesity, and other disease states. Namely, we discuss the fact that anabolic resistance exists as a dimmer switch, capable of varying from higher to lower levels of resistance, to the main anabolic stimuli of feeding and exercise depending on the population. Moreover, we review the evidence on whether increased physical activity and targeted exercise can be leveraged to restore the sensitivity of skeletal muscle tissue to dietary amino acids regardless of the population.

Can an intradialytic snack model compensate the catabolic impact of hemodialysis?

BACKGROUND AND AIMS

Hemodialysis (HD) has a catabolic effect caused by alterations in protein metabolism, increase in resting energy expenditure (REE) and protein needs due to inflammation, HD circuit blood and heat losses, protein losses to dialysate and HD filter membrane biocompatibility. We aim to determine, as a proof of concept, whether a standardized intradialytic snack model is adequate to compensate the catabolic impact of HD.

METHODS

Cross sectional analysis of patients' chosen intradialytic intake according to a snack model, at the day of blood sample collection of three different months. As targets for the compensation of the catabolic impact of HD, we considered 316.8kCal (1.32 (±0.18) kcal/min - 240' of HD) for the estimated increase in REE and at least 7 g of protein losses/HD treatment.

RESULTS

A total of 448 meals were analyzed, with 383 given during daytime shifts. No intolerances were registered. The mean nutritional profile of the daytime shifts intakes was 378.8 (±151.4) kcal, 13.5 (±7.2) g of protein, 676 (±334) mg of sodium (Na), 361.0 (±240.3) mg of potassium (K) and 249.3 (±143.0) mg of phosphates (P). We found that 68% of the meals provided an intake ≥316.8kCal and 82% a protein intake ≥ 7 g, with a significant association found between treatment shift and energy (p < 0.028), protein (p < 0.028), lipids (p < 0.004), Na (p < 0.004), K (p < 0.009) and P (p < 0.039) intakes.

CONCLUSIONS

We found that this intradialytic snack model meets the target for the treatment-related increases in protein and energy needs. Although sodium intake was found to be high, potassium and phosphate intake was considered adequate.

Chronic Kidney Disease and Nutrition Support

Individuals with chronic kidney disease (CKD), particularly those undergoing maintenance dialysis, are prone to protein-energy wasting (PEW), the latter of which can be ameliorated with different methods of nutrition support. Dietary counseling guided by dietitians is the key for preventing and managing PEW in CKD. If dietary counseling per se fails to meet the recommended energy and protein requirements, the addition of oral nutrition supplements (ONSs) would be necessary. When these initial measures cannot attain the recommended energy and protein requirements, nutrition support, including enteral tube feeding or parenteral nutrition (PN), should be considered as a viable option to improve nutrition status. Partial PN, comprising intraperitoneal PN (IPPN) and intradialytic PN (IDPN) therapies, may be attempted as supplemental nutrition support in patients with PEW requiring peritoneal dialysis and hemodialysis, respectively. Despite the debatable effectiveness of IPPN for patients undergoing peritoneal dialysis, it remains a feasible means in these patients. The indications for IPPN in patients undergoing peritoneal dialysis include inadequate dietary intake of energy and protein, and barriers of oral intake and other forms of enteral supplementation such as issues with suitability, tolerance, and compliance. Nonetheless, in the case of spontaneous dietary consumption of energy and protein meeting the difference between the IDPN provision and the nutrition targets, the use of IDPN is rational. In patients with PEW and malfunctioning gastrointestinal tract, as well as those whose enteral intake (with or without partial PN) is below the recommended nutrient requirements, total PN becomes a relevant nutrition intervention.

Frequency of Intradialytic Hypotension Events Do Not Increase with Oral Nutritional Supplementation during Hemodialysis Treatment: A Randomized Controlled Trial

OBJECTIVE

This study aimed to compare the effect of the use of a renal-specific oral nutritional supplement (RS-ONS) during hemodialysis sessions and the use of RS-ONS at home on the incidence of intradialytic hypotension.

METHODS

A single-center, 12-week, open-label, randomized controlled clinical trial was conducted. The intervention was a RN-ONS divided into two portions: 100 and 137 mL. The first portion was given after 1 hour of hemodialysis (HD) treatment, while the second portion was given 45 minutes before the end of HD. The research staff registered the baseline and final nutritional parameters and systolic arterial pressure (SAP) from the screen of the HD device during 36 HD sessions. Hypotension symptoms were also recorded every hour during each HD session. The nutritional and functional status was also assessed.

RESULTS

We registered a total of 16 hypotensive events during 1082 HD sessions: 9 were in patients supplemented at home (551 HD sessions) and 7 occurred in patients supplemented during HD P = .668. Incidence of intradialytic hypotension (IH) during 1082 HD sessions was 1.4%. The total malnutrition inflammation score (MIS) decreased in both groups (P < .01), and the percentage of cachexia improved in the supplemented-during-HD group (P < .05).

CONCLUSIONS

In this randomized controlled trial, intradialytic hypotension events did not increase with the RS-ONS during HD treatment. This strategy appears to be a safe anabolic nutritional strategy for the prevention of PEW, selecting stable patients and administering a fractioned volume of the supplement after the first hour of HD treatment. More studies with larger samples size are required to confirm these findings.

The modulating effect of dietary protein intake on mortality in long-term hemodialysis patients: A nationwide population-based study

AIMS OF THE STUDY

A high prevalence of protein-energy wasting and malnutrition among uremic patients is associated with an increase in morbidity and mortality. We aimed to investigate the modulating effect of daily dietary protein intake (DPI) evaluated by normalised protein catabolic rate (nPCR) on mortality in long-term haemodialysis (HD) patient from a nationwide population-based study.

METHODS USED TO CONDUCT THE STUDY

By Taiwan Renal Registry Data System between 2005 and 2012, we divided the long-term HD patients into average nPCR < 1.2 and nPCR ≥ 1.2 groups according to the current guideline. The relation of nPCR with three-year all-cause and cardiovascular (CV) mortality were evaluated. The cox regression method for predicted mortality by nPCR was used.

RESULTS OF THE STUDY

Among 88 330 HD patients, 58 122 (65.8%) patients were in average nPCR < 1.2 group and 30 208 (34.2%) in average nPCR ≥ 1.2 group. Both all-cause and cardiovascular (CV) mortality risks were increased in nPCR < 1.2 group after adjusting for demographics and laboratories cofactors in our multivariate cox regression model. Patients with nPCR < 1.2 and albumin ≥ 3.7 had a higher adjusted hazard ratio (aHR) for all-cause and CV mortality (1.16 [95% confidence interval (CI): 1.07-1.25, P < .001]; 1.15 [95% CI: 1.02-1.31, P = .03], respectively), compared with the reference group with nPCR ≥ 1.2 and albumin ≥ 3.7. Interestingly, there was no difference in mortality risk between low DPI subgroup (nPCR < 1.2 and Alb < 3.7) and the reference group (nPCR ≥ 1.2 and Alb < 3.7). Further stratification analysis revealed that low DPI subgroup (nPCR < 1.2, Alb ≥ 3.7 and TC ≥ 150) had an increased risk of both all-cause and CV mortality (aHR 1.14 [95% CI: 1.04-1.25, P = .005]; aHR 1.17 [95% CI: 1.02-1.35, P = .026], respectively).

CONCLUSIONS DRAWN FROM THE STUDY

Low DPI (as presented by nPCR) independently correlated with all-cause and CV mortality among HD patients. Mortality risks were higher in low DPI patients even with normoalbuminaemia and non-hypocholesterolaemia. Further investigations on the importance of increasing DPI in HD patients is warranted.

ESPEN guideline on clinical nutrition in hospitalized patients with acute or chronic kidney disease

Acute kidney disease (AKD) - which includes acute kidney injury (AKI) - and chronic kidney disease (CKD) are highly prevalent among hospitalized patients, including those in nephrology and medicine wards, surgical wards, and intensive care units (ICU), and they have important metabolic and nutritional consequences. Moreover, in case kidney replacement therapy (KRT) is started, whatever is the modality used, the possible impact on nutritional profiles, substrate balance, and nutritional treatment processes cannot be neglected. The present guideline is aimed at providing evidence-based recommendations for clinical nutrition in hospitalized patients with AKD and CKD. Due to the significant heterogeneity of this patient population as well as the paucity of high-quality evidence data, the present guideline is to be intended as a basic framework of both evidence and - in most cases - expert opinions, aggregated in a structured consensus process, in order to update the two previous ESPEN Guidelines on Enteral (2006) and Parenteral (2009) Nutrition in Adult Renal Failure. Nutritional care for patients with stable CKD (i.e., controlled protein content diets/low protein diets with or without amino acid/ketoanalogue integration in outpatients up to CKD stages four and five), nutrition in kidney transplantation, and pediatric kidney disease will not be addressed in the present guideline.

Slipping Through the Pores: Hypoalbuminemia and Albumin Loss During Hemodialysis

Hypoalbuminemia results when compensatory mechanisms are unable to keep pace with derangements in catabolism/loss and/or decreased synthesis of albumin. Across many disease states, including chronic kidney disease (CKD), hypoalbuminemia is a well-established, independent risk factor for adverse outcomes, including mortality. In the setting of CKD, reduced serum albumin concentrations are often a manifestation of protein-energy wasting, a state of metabolic and nutritional alterations resulting in reduced protein and energy stores. The progression of CKD to kidney failure and the initiation of maintenance hemodialysis (HD) further predisposes an already at-risk population toward hypoalbuminemia such that approximately 60% of HD patients have albumin concentrations <4.0 g/dl. Albumin loss into the dialysate through the dialyzer appears to be a potentially modifiable cause of hypoalbuminemia in some patients. A group of newer dialyzers for maintenance HD-sometimes termed protein-leaking or medium cut-off membranes-aim to improve clearance of middle molecules (vs high flux dialyzers) but are associated with increased albumin losses. In this article, we will examine the impact of dialyzer selection on albumin losses during conventional HD, including the clinical relevance of such losses on serum albumin levels. Data on the clinical relevance of albumin losses during dialysis and current gaps in the evidence base are also discussed.

Uremic Sarcopenia and Its Possible Nutritional Approach

Uremic sarcopenia is a frequent condition present in chronic kidney disease (CKD) patients and is characterized by reduced muscle mass, muscle strength and physical performance. Uremic sarcopenia is related to an increased risk of hospitalization and all-causes mortality. This pathological condition is caused not only by advanced age but also by others factors typical of CKD patients such as metabolic acidosis, hemodialysis therapy, low-grade inflammatory status and inadequate protein-energy intake. Currently, treatments available to ameliorate uremic sarcopenia include nutritional therapy (oral nutritional supplement, inter/intradialytic parenteral nutrition, enteral nutrition, high protein and fiber diet and percutaneous endoscopic gastrectomy) and a personalized program of physical activity. The aim of this review is to analyze the possible benefits induced by nutritional therapy alone or in combination with a personalized program of physical activity, on onset and/or progression of uremic sarcopenia.

Pharmacoepidemiology for nephrologists (part 1): concept, applications and considerations for study design

Randomized controlled trials on drug safety and effectiveness are the foundation of medical evidence, but they may have limited generalizability and be unpowered to detect rare and long-term kidney outcomes. Observational studies in routine care data can complement and expand trial evidence on the use, safety and effectiveness of medications and aid with clinical decisions in areas where evidence is lacking. Access to routinely collected large healthcare data has resulted in the proliferation of studies addressing the effect of medications in patients with kidney diseases and this review provides an introduction to the science of pharmacoepidemiology to critically appraise them. In this first review we discuss the concept and applications of pharmacoepidemiology, describing methods for drug-utilization research and discussing the strengths and caveats of the most commonly used study designs to evaluate comparative drug safety and effectiveness.

The effect of protein-enriched snacks on serum albumin concentration in non-selected haemodialysis patients

OBJECTIVE

Serum albumin level is not only one of the protein-energy wasting criteria but also a powerful marker of mortality in patients on haemodialysis (HD) treatment. The study aimed to assess the effect of a protein-enriched snack given during HD treatment on serum albumin level.

DESIGN AND METHODS

This prospective, single-centre, observational, non-randomized 16-month study was sub-divided into four 4-month periods. Patients on hemodialysis for more than three months and receiving a regular standard snack (8.8 g of protein) during the HD session were included and assigned during four four-month periods to receive either the standard snack or a protein-enriched snack (28.7 g). Patients were not selected based on nutritional criteria.

RESULTS

Sixty-six patients completed the study. Serum albumin levels significantly increased, from 3.43 ± 0.28 g/dl in the first period (standard snack) to 3.62 ± 0.32 g/dl (p < 0.0001) in the second period (enriched snack). In the third period (standard snack), albumin levels remained stable (3.61 ± 0.35 g/dl). After the fourth period (enriched snack), serum albumin levels further increased significantly (3.69 ± 0.30 g/dl; p = 0.05 and p = 0.007, respectively). Weight and normalized protein nitrogen appearance remained stable during the 16-month study period.

CONCLUSIONS

This study suggests that the intake of a protein-enriched snack during HD treatment, independently from baseline serum albumin level, could significantly increase their serum albumin levels. Serum albumin level is a powerful predictor of mortality; therefore, this simple and effective action could be of real interest to improve patients' outcomes.

Development of muffins as dialysis snacks for patients undergoing hemodialysis: results of chemical composition and sensory analysis

Objective

This study aimed to develop two non-industrial food products as financially accessible options to prevent and treat malnutrition in hemodialysis (HD) patients. These food products were developed and intended for use as dialysis snacks.

Methods

This is a cross-sectional and multi-step study. First, 183 adult HD patients (55 ± 14 years; 50.8% males), replied to a questionnaire with their food preferences regarding taste (salty, sweet, bitter, sour) and consistency (liquid, solid, pasty) for a dialysis snack. Most patients preferred a food product with a solid consistency (90%) and a salty flavor (81.4%). Second, three muffin formulations of fine herbs were developed; one enriched with whey protein concentrate (WPC), a second with textured soy protein (TSP) and a third standard formulation without protein for comparison with the protein-enriched muffins, for which the chemical and nutritional compositions were analyzed. In the third step, 60 patients on HD (61 ± 15 years; 53% males) were enrolled in a sensory analysis by applying a 9-point structured hedonic scale, ranging from “extremely liked” (score 9) to “extremely disliked” (score 1).

Results

When compared with the standard formulation, the formulations enriched with WPC and TSP protein had a significantly higher amount of protein/serving (Standard: 5.9 ± 0.3 g vs WPC: 14.5 ± 0.9 g and TSP 10.8 ± 0.7 g; P < 0.05) but a lower amount of carbohydrate (Standard: 13.1 ± 2.2 g vs WPC: 5.6 ± 0.8 g and TSP 6.0 ± 1.2 g vs; P < 0.05). The mineral content/serving of the protein-enriched muffins was low in phosphorus (50 mg) and sodium (180 mg). The potassium content/serving was moderate for the WPC muffin (225.2 mg) and low for the TSP muffin (107.9 mg). The acceptability index (AI) for the enriched protein muffins was higher than 70% and similar to the standard formulation.

Conclusion

The muffins with fine herbs and enriched with protein were well-accepted by all patients and appropriate to serve as dialysis snacks for HD patients.

Impacts of admission serum albumin levels on short-term and long-term mortality in hospitalized patients

AIM

The aim of this study is to assess the association between admission serum albumin and short- and long-term mortality in all hospitalized patients.

DESIGN

A single-center cohort study.

METHODS

A retrospective cohort of all adult hospitalized patients at a tertiary referral hospital between January 2009 and December 2013 were analysed. Admission serum albumin was stratified into six groups: ≤2.4, 2.5-2.9, 3.0-3.4, 3.5-3.9, 4.0-4.4 and ≥4.5 g/dl. The outcomes of interest were in-hospital mortality, length of hospital stay and 1-year mortality. Serum albumin of 4-4.4 g/dl was selected as a reference group for outcome comparison.

RESULTS

A total of 14 075 patients were studied. Admission serum albumin of ≥4.5 g/dl had the lowest in-hospital and 1-year mortality with progressively increased in-hospital mortality observed with decreased admission serum albumin. In adjusted analysis, compared with serum albumin of 4.0-4.4 g/dl, serum albumin of ≤2.4, 2.5-2.9, 3.0-3.4 and 3.5-3.9 were significantly associated with increased in-hospital and 1-year mortality. In contrast, serum albumin of ≥4.5 g/dl was significantly associated with lower 1-year mortality but not in-hospital mortality. Admission serum albumin <4.0 g/dl was significantly associated with a prolonged hospital stay, while admission serum albumin of ≥4.5 g/dl was significantly associated with shorter hospital stay, compared with serum albumin of 4.0-4.4 g/dl.

CONCLUSION

Low albumin level at admission was progressively associated with increased short- and long-term mortality in all hospitalized patients even when albumin level was considered in normal range.

Oral protein-based supplements versus placebo or no treatment for people with chronic kidney disease requiring dialysis

BACKGROUND

Malnutrition is common in patients with chronic kidney disease (CKD) on dialysis. Oral protein-based nutritional supplements are often provided to patients whose oral intake is otherwise insufficient to meet their energy and protein needs. Evidence for the effectiveness of oral protein-based nutritional supplements in this population is limited.

OBJECTIVES

The aims of this review were to determine the benefits and harms of using oral protein-based nutritional supplements to improve the nutritional state of patients with CKD requiring dialysis.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 12 December 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of patients with CKD requiring dialysis that compared oral protein-based nutritional supplements to no oral protein-based nutritional supplements or placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for eligibility, risk of bias, and extracted data from individual studies. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference and 95% CI for continuous outcomes.

MAIN RESULTS

Twenty-two studies (1278 participants) were included in this review. All participants were adults on maintenance dialysis of whom 79% were on haemodialysis (HD) and 21% peritoneal dialysis. The follow-up period ranged from one to 12 months. The majority of studies were at unclear risk of selection, performance, and reporting bias. The detection bias was high for self-reported outcomes. Oral protein-based nutritional supplements probably lead to a higher mean change in serum albumin compared to the control group (16 studies, 790 participants: MD 0.19 g/dL, 95% CI 0.05 to 0.33; moderate certainty evidence), although there was considerable heterogeneity in the combined analysis (I² = 84%). The increase was more evident in HD participants (10 studies, 526 participants: MD 0.28 g/dL, 95% CI 0.11 to 0.46; P = 0.001 for overall effect) and malnourished participants (8 studies, 405 participants: MD 0.31 g/dL, 95% CI 0.10 to 0.52, P = 0.003 for overall effect). Oral protein-based nutritional supplements also probably leads to a higher mean serum albumin at the end of the intervention (14 studies, 715 participants: MD 0.14 g/dL, 95% CI 0 to 0.27; moderate certainty evidence), however heterogeneity was again high (I² = 80%). Again the increase was more evident in HD participants (9 studies, 498 participants: MD 0.21 g/dL, 95% CI 0.03 to 0.38; P = 0.02 for overall effect) and malnourished participants (7 studies, 377 participants: MD 0.25 g/dL, 95% CI 0.02 to 0.47; P = 0.03 for overall effect). Compared to placebo or no supplement, low certainty evidence showed oral protein-based nutritional supplements may result in a higher serum prealbumin (4 studies, 225 participants: MD 2.81 mg/dL, 95% CI 2.19 to 3.43), and mid-arm muscle circumference (4 studies, 216 participants: MD 1.33 cm, 95% CI 0.24 to 2.43) at the end of the intervention. Compared to placebo or no supplement, oral protein-based nutritional supplements may make little or no difference to weight (8 studies, 365 participants: MD 2.83 kg, 95% CI -0.43 to 6.09; low certainty evidence), body mass index (9 studies, 368 participants: MD -0.04 kg/m², 95% CI -0.74 to 0.66; moderate certainty evidence) and lean mass (5 studies, 189 participants: MD 1.27 kg, 95% CI -1.61 to 4.51; low certainty evidence). Due to very low quality of evidence, it is uncertain whether oral protein-based nutritional supplements affect triceps skinfold thickness, mid-arm circumference, C-reactive protein, Interleukin 6, serum potassium, or serum phosphate. There may be little or no difference in the risk of developing gastrointestinal intolerance between participants who received oral protein-based nutritional supplements compared with placebo or no supplement (6 studies, 426 participants: RR 2.81, 95% CI 0.58 to 13.65, low certainty evidence). It was not possible to draw conclusions about cost or quality of life, and deaths were not reported as a study outcome in any of the included studies.

AUTHORS' CONCLUSIONS

Overall, it is likely that oral protein-based nutritional supplements increase both mean change in serum albumin and serum albumin at end of intervention and may improve serum prealbumin and mid-arm muscle circumference. The improvement in serum albumin was more evident in haemodialysis and malnourished participants. However, it remains uncertain whether these results translate to improvement in nutritional status and clinically relevant outcomes such as death. Large well-designed RCTs in this population are required.

Intradialytic Nutrition and Hemodialysis Prescriptions: A Personalized Stepwise Approach

Dialysis and nutrition are two sides of the same coin—dialysis depurates metabolic waste that is typically produced by food intake. Hence, dietetic restrictions are commonly imposed in order to limit potassium and phosphate and avoid fluid overload. Conversely, malnutrition is a major challenge and, albeit to differing degrees, all nutritional markers are associated with survival. Dialysis-related malnutrition has a multifactorial origin related to uremic syndrome and comorbidities but also to dialysis treatment. Both an insufficient dialysis dose and excessive removal are contributing factors. It is thus not surprising that dialysis alone, without proper nutritional management, often fails to be effective in combatting malnutrition. While composite indexes can be used to identify patients with poor prognosis, none is fully satisfactory, and the definitions of malnutrition and protein energy wasting are still controversial. Furthermore, most nutritional markers and interventions were assessed in hemodialysis patients, while hemodiafiltration and peritoneal dialysis have been less extensively studied. The significant loss of albumin in these two dialysis modalities makes it extremely difficult to interpret common markers and scores. Despite these problems, hemodialysis sessions represent a valuable opportunity to monitor nutritional status and prescribe nutritional interventions, and several approaches have been tried. In this concept paper, we review the current evidence on intradialytic nutrition and propose an algorithm for adapting nutritional interventions to individual patients.

Feeding during dialysis-risks and uncertainties

Allowing dialysis patients to eat during the treatment is controversial. It is, therefore, no surprise that practices and policies with respect to intradialytic food consumption vary considerably from unit to unit and from country to country. Those who defend the position of feeding during dialysis reason that intradialytic meals offer a supervised and effective therapy for protein-energy wasting. Those who take the opposite view argue that intradialytic food intake should be avoided for the following three reasons. First, interventional studies show that eating during dialysis causes a clinically significant reduction in systemic blood pressure during the postprandial period and elevates the risk of symptomatic intradialytic hypotension; the latter is associated with increased mortality risk. Second, clinical studies have shown that eating during dialysis interferes with the adequacy of the delivered dialysis, whereas eating 2-3 h before the dialysis session has no impact on the efficiency of the subsequent dialysis treatment. And third, randomized studies show that eating during dialysis focus on the positive outcomes but do not adequately balance this potential benefit against the risk of intradialytic hemodynamic instability and poor quality of delivered dialysis. Even after half a century of providing long-term dialysis, definitive randomized trials that balance risks and benefits of eating during dialysis are missing. These knowledge gaps require randomized trials. Since there is a real possibility of harm with eating during dialysis, we caution that instead of encouraging the widespread use of intradialytic meals, practices and policies should focus on adequate nutrient intake during the interdialytic interval.

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.

Results from the randomized controlled IHOPE trial suggest no effects of oral protein supplementation and exercise training on physical function in hemodialysis patients

Few long-term studies have assessed whether changes in both diet and exercise can improve the health and quality of life (QOL) of hemodialysis (HD) patients. Here we examined whether 12 months of intradialytic protein supplementation and endurance exercise improves physical function, risk of cardiovascular disease (CVD), and QOL in HD patients in a randomized controlled trial (RCT). A total of 138 HD patients (average age 58 years) were assigned for 12 months to control, intradialytic protein, or protein plus exercise groups. The protein and protein plus exercise groups consumed an oral protein supplement (30 grams of whey) three days/week during dialysis. The protein plus exercise group cycled for 30-45 minutes during dialysis treatment. The primary outcome was change in physical function at 12 months, assessed by a shuttle walk test. Secondary outcomes included arterial stiffness, blood pressure, body composition, muscle strength, markers of nutritional status, and QOL. Assessments were conducted at baseline, 6 and 12 months. In total, 101 patients completed the intervention. There were no significant differences between groups in shuttle walk test performance from baseline to 12 months. There were trends for improvements in some secondary measures of physical function and strength in the protein and protein plus exercise groups at six or 12 months, but these did not reach statistical significance. Thus, our trial did not demonstrate significant improvements in markers of physical function, risk of CVD or QOL after one year of intradialytic oral OPS and aerobic exercise training. More comprehensive lifestyle management may be needed to uncover robust improvements in the health and QOL of HD patients.

Oral nutritional supplements and 30-day readmission rate in hypoalbuminemic maintenance hemodialysis patients

INTRODUCTION

Hemodialysis (HD) patients are hospitalized nearly twice yearly, and 35% of these patients are rehospitalized within 30-days postdischarge. We hypothesized that monitored oral nutritional supplementation (ONS) during HD treatment may decrease readmissions.

METHODS

A cohort of maintenance HD patients, treated at a large dialysis organization, who were hospitalized with a postdischarge albumin of ≤3.5 g/dL, without documented ONS use 90 days prior to the index hospitalization were identified. Individuals who received monitored intradialytic ONS postdischarge were compared to those without receipt of ONS. The outcome of interest was 30-day hospital readmissions. Logistic regression was used to assess the association between ONS receipt and 30-day readmission events, with adjustment for case-mix and laboratory variables.

FINDINGS

Of 5479 eligible patients, ONS was prescribed to 1420 individuals. Mean age was 64.6 ± 14.1 (SD) years; median dialysis vintage was 3.9 years. There were 274 (19%) readmissions among ONS recipients vs. 1571 (38.7%) among controls during the 30-day follow-up period. Individuals who did not receive ONS had increased odds of readmission [OR 2.26 (95% CI 1.02, 2.53)] in 30 days, as compared to those who did receive ONS postdischarge. In sensitivity analyses using a propensity score matched cohort, the odds ratio of readmissions within 30 days postdischarge was 1.71 (95% CI: 1.42, 2.07) for individuals who did not receive ONS as compared to those who received ONS.

DISCUSSION

Consumption of ONS during HD sessions is associated with reduced hospital readmission rates among in-center maintenance HD with severe hypoalbuminemia at 30 days post-hospital discharge.

CKD autophagy activation and skeletal muscle atrophy-a preliminary study of mitophagy and inflammation

BACKGROUND/OBJECTIVES

Long-lived proteins and organelles, such as mitochondria and the sarcoplasmic reticulum, are degraded by autophagy. However, the specific role of autophagy in chronic kidney disease (CKD) muscle atrophy is still undefined.

SUBJECTS/METHODS

This was a cross-sectional study with 20 subjects and 11 controls. Autophagy induction was studied in human skeletal muscle biopsies from CKD patients and controls by comparing the cross-sectional areas of muscle fibers, protein, and mRNA expression of autophagy-related genes and the appearance of autophagosomes.

RESULTS

The cross-sectional area of muscle fibers was decreased in CKD patients as compared with the control group. CKD was associated with activated autophagy and mitophagy, as measured by the elevated mRNA and protein expression of BNIP3, (microtubule-associated proteins 1 A/1B light chain 3, also MAP1LC3) LC3, p62, PINK1, and PARKIN in the skeletal muscle and isolated mitochondria of the CKD group. Electron microscopy and immunohistofluorescence analysis showed mitochondrial engulfment by autophagosomes. Mitophagy was further demonstrated by the colocalization of LC3 and p62 puncta with the mitochondrial outer membrane protein TOM20. In addition, degradative FOXO3 (Forkhead box O3) was activated and synthetic mTOR (mammalian target of rapamycin) was inhibited, whereas the upstream mediators VPS34 (class III PI3-kinase) and AKT (protein kinase B, PKB) were activated in CKD patients.

CONCLUSIONS

Hyperactive autophagy and mitophagy may play important roles in CKD muscle atrophy. Autophagy was activated by FOXO3 translational factors in the skeletal muscle tissues of CKD patients, which maybe a new way of intervention for CKD muscle atrophy.

Pilot Study of the Effects of High-Protein Meals During Hemodialysis on Intradialytic Hypotension in Patients Undergoing Maintenance Hemodialysis

OBJECTIVE

Patients undergoing hemodialysis (HD) have high protein and energy requirements, and protein-energy wasting is common and associated with poor outcomes. Eating during dialysis may improve nutritional status by counteracting the catabolic effects of HD treatment; but eating during HD may be discouraged because of concerns of postprandial hypotension. However, little data are available to support this practice. In this study, we hypothesized that high-protein meals during HD do not lead to symptomatic intradialytic hypotension events.

DESIGN

A 9-week, nonrandomized, parallel-arm study.

SETTING

A single in-center HD clinic.

SUBJECTS

Eighteen patients undergoing HD from 2 shifts completed the study. Patients were aged 62 ± 16 years with dialysis vintage of 3.4 ± 2.6 years.

INTERVENTION

Patients in the intervention group (n = 9) undergoing HD received meals of ∼30 g protein and ∼1/3 daily recommended intakes of sodium, potassium, phosphorus, and fluid during dialysis for 25 consecutive HD sessions. The control group (n = 9) completed all aspects of the study including a visit by study personnel but were not given meals. The 25 consecutive sessions before the start of the intervention/control phase were used as a baseline comparison for each patient.

MAIN OUTCOME MEASURE

Symptomatic hypotension event frequency.

RESULTS

In the intervention arm, there were 19 symptomatic hypotension events in 5 patients prestudy and 18 events in 6 patients during the study. In the control arm, there were 16 events in 7 patients prestudy and 13 events in 7 patients during the study. Change in the frequency of symptomatic hypotension events from prestudy to during study was not different between groups (P = .71). There was no effect of meals on nutritional status, but patients reported positive attitudes toward receiving meals during dialysis.

CONCLUSION

High-protein meals during HD did not increase symptomatic hypotension events. Larger, longer term studies are needed to confirm these results and evaluate whether high-protein meals on dialysis benefit nutritional status and clinical outcomes.

Survival in patients on hemodialysis: Effect of gender according to body mass index and creatinine

Background

The association of a higher body mass index (BMI) with better survival is a well-known “obesity paradox” in patients on hemodialysis (HD). However, men and women have different body compositions, which could impact the effect of BMI on mortality. We investigated the effect of gender on the obesity-mortality relationship in Korean patients on HD.

Methods

This study included 2,833 maintenance patients on HD from a multicenter prospective cohort study in Korea (NCT00931970). The relationship between categorized BMI and gender-specific mortality was evaluated by an adjusted Cox proportional hazard model with restricted cubic spline analyses and the Competing risk analysis. We also investigated the effect of changes in BMI over 12 months and serum creatinine level on survival in male and female patients on HD.

Results

The mean BMI was 22.6 ± 3.3 kg/m² and the mean follow up duration was 24.2 ± 3.4 months. The patients with the highest quintile of BMI (≥25.1 kg/m²) showed lower mortality (subdistributional hazard ratio [SHR] = 0.63, 95% confidence interval [CI] = 0.43–0.93, P = 0.019) compared with those with the reference BMI quintile. When analyzed by gender, male patients with a BMI over 25.1 kg/m² had lower mortality risk (HR = 0.43, 95% CI = 0.25–0.75, P = 0.003); however, no significant difference was found in female patients. Increased BMI after 12 months and high serum creatinine were associated with better survival only in male patients on HD.

Conclusions

BMI could be used as a risk factor for mortality in male patients on HD. However, the mortality of female patients on HD was not related with baseline and follow-up BMI. This suggests that BMI is a good surrogate marker of lean body composition, especially in male patients on HD.

The Relationship Between Intradialytic Nutrition and Gastrointestinal Symptoms Using a Modified Version of the Gastrointestinal Symptom Rating Scale

OBJECTIVE

Intradialytic nutrition has been shown to improve nutritional status in maintenance hemodialysis (HD) patients but remains controversial due in part to concerns over hemodynamic stability and gastrointestinal (GI) distress. There are limited data on the relationship between intradialytic nutrition and GI symptoms, possibly due to the lack of a validated tool. Therefore, we intended to validate a questionnaire to measure GI symptoms associated with a single HD treatment and determine the relationship between intradialytic nutrition and GI symptoms.

DESIGN

Cross-sectional study. Forty-eight maintenance HD patients.

MAIN OUTCOME MEASURE

GI symptoms and dietary intake during HD treatment.

RESULTS

In general, we found acceptable internal consistency (Cronbach's alpha >0.5, exception reflux domain) and repeatability in all 5 domains of a modified version of the Gastrointestinal Symptom Rating Scale. The prevalence of GI symptoms associated with a single HD treatment (generalized score greater than 1) was 54.2, 43.7, 6.2, 41.7, and 45.8% for the abdominal pain, indigestion, reflux, diarrhea, and constipation domains, respectively. More than two-thirds of patients chose to eat during treatment (168.6 ± 165.6 kcal) with the most commonly consumed items being candy, oral supplements, and cookies. There was no difference in GI symptoms among patients who did or did not eat (P > .05). However, the amount of total dietary fat and fiber consumed during treatment was associated with greater indigestion (P < .05) prior to accounting for outliers or multiple comparisons.

CONCLUSION

In this sample, the modified version of the Gastrointestinal Symptom Rating Scale was a generally valid tool for measuring GI symptoms associated with a single HD treatment. Patients who ate during treatment did not experience greater GI symptoms than those who did not; however, high amounts of fat and fiber may be associated with greater GI symptoms. Prospective trials should examine the relationship between GI symptoms and dietary intake during treatment in HD patients.

Children tolerate intradialytic oral nutrition

BACKGROUND

People undergoing haemodialysis (HD) often have poor nutrition, which in turn can contribute to worse outcomes. Inadequate nutrition has a particularly deleterious effect on growth and neurocognitive development, as well as mortality, in children and adolescents. Nutritional supplementation can improve outcomes but can be difficult to administer.

OBJECTIVE

Determine the tolerability of intradialytic oral nutrition in children and adolescents.

DESIGN

A cross-sectional quality improvement study in an outpatient paediatric HD unit. Intervention was intradialytic oral nutritional supplementation provided as protein bars and/or meals.

SUBJECTS

Children and adolescents undergoing outpatient HD who were able to participate in surveys and eat by mouth.

MEASUREMENTS

Adverse effects and symptoms on nurse- and patient-reported surveys, respectively. Relationships between the predictor variables and the outcomes were assessed using generalised estimating equations.

RESULTS

The majority of children felt better after eating on dialysis (72%) with no adverse effects (80%). On unadjusted analyses and confirmed with generalised estimating equation modelling, children who reported being hungry felt better after eating on dialysis, despite being more likely to have adverse effects.

CONCLUSION

The study demonstrates that our children and adolescents feel better after eating on HD with minimal adverse effects. The finding that hungry patients are more likely to feel better despite having a higher likelihood of an adverse effect demonstrates the tolerability of eating on HD. Intradialytic oral nutrition could be a safe and well-tolerated opportunity to provide supplemental nutrition to paediatric HD patients and improve outcomes.

Effects of Oral Nutritional Supplements on Mortality, Missed Dialysis Treatments, and Nutritional Markers in Hemodialysis Patients

OBJECTIVE

Protein-energy wasting is common in end-stage renal disease patients undergoing dialysis and is strongly associated with mortality and adverse outcomes. Intradialytic oral nutritional supplements (ONS) reduce risk of mortality in these patients. Large studies characterizing the impact of ONS on other outcomes are lacking. We assessed the associations between administration of ONS and clinical and nutritional outcomes.

DESIGN

Retrospective evaluation of a pilot program providing ONS to patients at a large dialysis organization in the United States. The pilot program provided ONS to in-center hemodialysis patients with serum albumin ≤3.5 g/dL at 408 facilities.

SUBJECTS

ONS patients were compared to matched controls with serum albumin ≤3.5 g/dL, identified from facilities not participating in the ONS program (n = 3,374 per group).

INTERVENTION

Receipt of ONS.

MAIN OUTCOME MEASURES

Death, missed dialysis treatments, hospitalizations, serum albumin, normalized protein catabolic rate, and postdialysis body weight were abstracted from large dialysis organization electronic medical records.

RESULTS

There was a 69% reduction in deaths (hazard ratio = 0.31; 95% confidence interval = 0.25-0.39), and 33% fewer missed dialysis treatments (incidence rate ratio = 0.77; 95% confidence interval = 0.73-0.82) among ONS patients compared to controls (P < .001 for both). The effects of ONS on nutritional indices were mixed: serum albumin was lower, whereas normalized protein catabolic rate values, a surrogate for dietary protein intake, and postdialysis body weights were higher for ONS patients compared to controls during follow-up.

CONCLUSIONS

Our evaluation confirmed the beneficial effects of ONS in reducing mortality and improving some indices of nutritional status for hypoalbuminemic hemodialysis patients. We also report the novel finding that ONS can reduce the number of missed dialysis treatments. These results support the use of intradialytic ONS as an effective intervention to improve the outcomes in hemodialysis patients with low serum albumin.

Mechanisms and consequences of carbamoylation

Protein carbamoylation is a non-enzymatic post-translational modification that binds isocyanic acid, which can be derived from the dissociation of urea or from the myeloperoxidase-mediated catabolism of thiocyanate, to the free amino groups of a multitude of proteins. Although the term 'carbamoylation' is usually replaced by the term "carbamylation" in the literature, carbamylation refers to a different chemical reaction (the reversible interaction of CO₂ with α and ε-amino groups of proteins). Depending on the altered molecule (for example, collagen, erythropoietin, haemoglobin, low-density lipoprotein or high-density lipoprotein), carbamoylation can have different pathophysiological effects. Carbamoylated proteins have been linked to atherosclerosis, lipid metabolism, immune system dysfunction (such as inhibition of the classical complement pathway, inhibition of complement-dependent rituximab cytotoxicity, reduced oxidative neutrophil burst, and the formation of anti-carbamoylated protein antibodies) and renal fibrosis. In this Review, we discuss the carbamoylation process and evaluate the available biomarkers of carbamoylation (for example, homocitrulline, the percentage of carbamoylated albumin, carbamoylated haemoglobin, and carbamoylated low-density lipoprotein). We also discuss the relationship between carbamoylation and the occurrence of cardiovascular events and mortality in patients with chronic kidney disease and assess the effects of strategies to lower the carbamoylation load.