A Novel Approach for Managing Protein-Energy Wasting in People With Kidney Failure Undergoing Maintenance Hemodialysis: Rationale and Call for Trials

Longitudinal impact of extended-hours hemodialysis with a liberalized diet on nutritional status and survival outcomes: findings from the LIBERTY cohort

BACKGROUND

Protein-energy wasting (PEW), a unique weight loss linked to nutritional and metabolic abnormalities, is common in patients undergoing hemodialysis (HD) and associated with adverse outcomes. This study investigated whether extended-hours HD combined with a liberalized diet could overcome PEW and improve survival.

METHODS

The body mass index (BMI) and survival outcomes in patients undergoing extended-hours HD were evaluated for up to 8 years using data from the LIBeralized diet Extended-houRs hemodialysis Therapy (LIBERTY) cohort. Extended-hours HD was defined as weekly dialysis length ≥ 18 h.

RESULTS

The LIBERTY cohort included 402 patients who initiated extended-hours HD. An increase in the length and frequency of HD sessions was observed over time, with approximately 70% and 20% of patients undergoing extended-hours HD for > 21 h/week and > 3 sessions/week at 5 years, respectively. The BMI and percentage creatinine generation rate were maintained over time, with no substantial increase in the phosphorus and potassium levels. The estimated BMI initially increased, and thereafter plateaued over time in patients with a baseline BMI < 25 kg/m2, whereas it decreased gradually in patients with a baseline BMI ≥ 25 kg/m2 after several years from baseline. Ninety-one patients died, and 108 discontinued extended-hours HD during the median follow-up period of 6.2 years (interquartile range, 3.5-8.0), yielding a 5-year survival rate of 85%.

CONCLUSIONS

Extended-hours HD with a liberalized diet may help achieve favorable survival outcomes and maintain nutritional status. Thus, it is a promising treatment option for managing PEW in patients undergoing HD.

Plasma Metabolite Profiles Between In-Center Daytime Extended-Hours and Conventional Hemodialysis

Key Points

Significant differences in 39 plasma metabolites were observed between patients on extended-hours hemodialysis and those on conventional hemodialysis. Extended-hours hemodialysis had a lower lactate-to-pyruvate ratio and higher branched-chain amino acids than conventional hemodialysis. Extended-hours hemodialysis may have favorable metabolic and nutritional benefits for patients undergoing maintenance hemodialysis.

Background

Protein–energy wasting, characterized by disordered body protein catabolism resulting from metabolic and nutritional derangements, is associated with adverse clinical outcomes in patients undergoing hemodialysis. Extended-hours hemodialysis (≥6 hours per treatment session) offers both enhanced removal of uremic solutes and better fluid management, generally allowing more liberalized dietary protein and calorie intake. The aim of this study was to evaluate the difference in plasma metabolite profiles among patients receiving in-center daytime extended-hours hemodialysis and those receiving conventional hemodialysis.

Methods

Predialysis plasma samples were obtained from 188 patients on extended-hours hemodialysis (21.9 h/wk) and 286 patients on conventional hemodialysis (12.1 h/wk) in Japan in 2020 using capillary electrophoresis-mass spectrometry. Group differences were compared for 117 metabolites using Wilcoxon rank-sum tests with multiple comparisons and partial least squares discriminant analysis. In addition, propensity score–adjusted multiple regression analyses were performed to evaluate group differences for known uremic toxins, branched-chain amino acids, and lactate-to-pyruvate ratio (a possible surrogate marker of mitochondrial dysfunction).

Results

Significant differences were observed in 39 metabolites, largely consistent with the high variable importance for prediction in partial least squares discriminant analysis. Among known uremic toxins, uridine and hypoxanthine levels were significantly higher in the conventional hemodialysis group than in the extended-hours hemodialysis group, whereas trimethylamine N -oxide levels were higher in the extended-hours hemodialysis group than in the conventional hemodialysis group. Patients on extended-hours hemodialysis had higher levels of all branched-chain amino acids and a lower lactate-to-pyruvate ratio than those on conventional hemodialysis (significant difference of −8.6 [95% confidence interval, −9.8 to −7.4]).

Conclusions

Extended-hours hemodialysis was associated with a more favorable plasma metabolic and amino acid profile; however, concentrations of most uremic toxins did not significantly differ from those of conventional hemodialysis.

Why protein-energy wasting leads to faster progression of chronic kidney disease

PURPOSE OF REVIEW

Protein-energy wasting (PEW) is increasingly more prevalent as chronic kidney disease (CKD) progresses to more advanced stages. There is a global recognition of the importance of preventing and mitigating PEW in the CKD population not on dialysis given the goal of extending dialysis-free time and delaying dialysis initiation and growing evidence of the clinical consequences of PEW which include the risk of death, hospitalization and clinical conditions such as infections. We reviewed the association of PEW and the malnutrition characteristics indicative of PEW on CKD progression.

RECENT FINDINGS

Studies show the association between low serum albumin levels, low BMI, and diets with inadequate dietary energy and protein intake and CKD progression. Limited studies suggest low muscle mass impacts CKD progression. Optimizing nutrition by dietary management, including a moderately low protein (0.6-0.8 g/kg/day) and plant-based (>50% of protein source, known as PLADO) diet and as needed with supplementation [e.g. during acute kidney injury (AKI) event] administrated orally, enterally, or parenterally are the basis for the prevention and treatment of PEW in CKD and delaying CKD progression. Furthermore, other therapeutic methods such as treating or avoiding comorbidities and AKI, ensuring appropriate exercise and incremental transition to dialysis treatment may help ameliorate and prevent PEW development in CKD patients.

SUMMARY

Using tailored precision nutrition approaches and nutritional supplementation with or without other beneficial strategies may help prevent and treat PEW and its consequent occurrence of CKD progression.

[Nutrition for patients on dialysis]

Dietary recommendations for patients on dialysis are changing as our understanding of enteral microbiotal metabolism and bioavailability of nutrients from food improves.A diet low in phosphate and potassium is recommended for patients on hemodialysis. However, the absolute content does not reflect bioavailability: How much phosphate or potassium is taken up depends on food source (plant vs. animal) and to which grade it is processed. While both are nearly 100% bioavailable from industrially processed foods (additives such as dipotassium-phosphate and other salts), a much lower proportion is taken up from unprocessed plant foods high in fibre (ca. 20-40%). The DIET-HD study showed no significant association between dietary potassium and serum potassium in > 8 000 dialysis patients; and those with the highest low-processed, fresh plant-food consumption have the best survival. Dietary fibre improves colon transit time and thereby lessens symptoms of constipation. A diet low in sodium improves blood pressure and volume management in dialysis patients. The energy and protein requirements on dialysis are high: 25-35 kcal and 1-1,2 g protein per kg body weight per day (in relation to "ideal" body weight, if patient is overweight). Protein energy wasting is associated with higher stages of kidney disease, and malnutrition is associated with worse survival on dialysis. Nutritional status should be assessed on a regular basis using validated scores, and malnutrition should be addressed and treated.

A simple score for malnutrition-inflammation complex syndrome (MICS) is associated with the risk of mortality in Japanese patients undergoing maintenance hemodialysis

INTRODUCTION

Malnutrition-inflammation complex syndrome (MICS) is highly prevalent in patients undergoing hemodialysis. We determined the prognostic value of the Simple MICS score, calculated using a combination of age, body mass index, and serum concentrations of albumin, creatinine, and C-reactive protein.

METHODS

We retrospectively recruited 218 Japanese patients undergoing maintenance hemodialysis. The primary outcome was all-cause mortality, and the main exposure was the Simple MICS score. Cox proportional hazard regression analysis and logistic regression analysis were used to characterize the relationship between the Simple MICS score and mortality.

RESULTS

During a median 4.4-year follow-up period, 56 patients died. Multivariable-adjusted models showed that a higher Simple MICS score was associated with higher risks of mortality. The predictability for all-cause mortality of the Simple MICS score was significantly better than conventional nutrition-related indices.

CONCLUSION

The Simple MICS score can be used to stratify mortality risk in patients undergoing maintenance hemodialysis.

Deconstructing Disease-Related Malnutrition: A New Assessment Framework for Clinical Practice

Protein-energy wasting (PEW) is a key cause of functional impairment and poor health outcomes in people with chronic kidney disease. While PEW can be mitigated with nutrition therapy, it is a complex myriad of disorders with numerous interacting etiologies and corresponding presentations, which make it difficult to diagnose and manage in practice. A variety of scoring rubrics have been developed to facilitate malnutrition assessment. Although these tools have greatly benefited the recognition and treatment of PEW, the typical format of grading specified PEW indicators has the potential to overlook or overstate highly relevant individual-specific factors. This review presents a simple framework for malnutrition assessment that can be used to complement and evaluate conventional assessment tools. Unlike standard tools, which are designed to identify and rate malnutrition risk and severity, the malnutrition framework is conceptual model that organizes PEW assessment into three distinct, but interacting facets of PEW risk: nutrient balance, nutrition status, and malnutrition risk. The new framework encourages critical thinking about PEW risk that may help clinicians plan and interpret assessments to efficiently and effectively manage this condition.

Dietary protein and muscle wasting in chronic kidney disease: new insights

PURPOSE OF REVIEW

Muscle wasting is an important health problem in chronic kidney disease (CKD) patients. Protein restriction in the diet can be one of the main causes of muscle wasting in this population. In this review, we aimed to investigate the relationship between dietary protein intake and muscle wasting in CKD patients according to recent literature.

RECENT FINDINGS

The one of the main mechanisms responsible for the muscle wasting is the disturbances in skeletal muscle protein turnover. Muscle wasting primarily occurs when the rates of muscle protein breakdown exceed the muscle protein synthesis. Dietary protein intake represents an important role by causing a potent anabolic stimulus resulting a positive muscle protein balance. Compared to studies made in healthy populations, there are very limited studies in the literature about the relationship between dietary protein intake and muscle wasting in the CKD population. Majority of the studies showed that a more liberal protein intake is beneficial for muscle wasting in especially advanced CKD and hemodialysis population.

SUMMARY

Although evaluating muscle wasting in CKD patients, the amount of protein in the diet of patients should also be reviewed. Although excessive protein intake has some negative consequences on this patient group, a more liberated dietary protein intake should be taken into account in this patient group with muscle wasting and especially in dialysis patients.

A Higher Whole-Body Extracellular to Intracellular Water Ratio Is Associated with Increased Odds of Cognitive Impairment in Hemodialysis Patients

BACKGROUND

Cognitive impairment (CI) is highly prevalent in patients undergoing hemodialysis. Whether fluid overload with malnutrition as assessed by the ratio of extracellular water to intracellular water (ECW/ICW) is associated with CI in patients on maintenance hemodialysis (MHD) has yet to be studied.

OBJECTIVE

This study aimed to investigate the association between ECW/ICW and CI in patients with MHD.

METHODS

We conducted a multicenter, cross-sectional study that enrolled 3,025 adult patients with MHD. Cognitive function was assessed through the Mini-Mental State Examination. The ECW/ICW was derived from a portable body composition monitor and analyzed by quartiles.

RESULTS

23.04% of participants had CI in our study. The prevalence of CI tended to increase as the quartiles of the ECW/ICW ratio increased. Unadjusted analysis showed that participants in quartile 4 were 3.02 times more likely to have a CI compared to those in quartile 1. After adjusting for age, sex, education, smoking status, body mass index, dialysis vintage, history of hypertension, and history of stroke, the adjusted OR (95% CI) for the highest quartile of ECW/ICW ratio was 1.36 (1.01, 1.83) for CI compared with the lowest quartile. Interestingly, the association between ECW/ICW ratio and CI persisted across all subgroups stratified by age, gender, history of diabetes, and stroke. (p for interaction > 0.05 for all).

CONCLUSION

An increased ECW/ICW ratio is associated with higher odds of cognitive impairment in patients undergoing hemodialysis.