The association of intradialytic parenteral nutrition administration with survival in hemodialysis patients

Revisiting Intradialytic Parenteral Nutrition: How Can We Apply the Evidence in Clinical Practice?

Intradialytic parenteral nutrition (IDPN) remains a controversial nutrition support practice in hemodialysis. Multiple reviews and evidence-based clinical practice guidelines have been published in the past 20 years. Despite essentially looking at the same evidence, conclusions and recommendations vary significantly, leading to widespread uncertainty among clinicians on the value of and indications for IDPN. This paper aims to bring a clinical perspective to the current state of evidence and clinical practice, recognizing the strengths and weaknesses of current evidence and the clinical questions that remain unanswered, as well as providing guidance for using IDPN in clinical practice. IDPN should be considered a strategy to complement spontaneous oral intake in clinically stable patients receiving maintenance hemodialysis or who have or are at risk of malnutrition and who have substantial but not adequate protein and/or energy intake. There is a clear need for robust randomized controlled trials evaluating the impact of IDPN in appropriately selected patients. Additionally, future trials should include patient-centered outcome measures such as appetite, spontaneous oral intake, quality of life, and reliable measures of nutritional status.

Effects of the Malnutrition-Eat Additional Meal (MEAM) Diet on the Serum Levels of Albumin and C-Reactive Protein in Hemodialysis Patients

The main objective of this project was to evaluate the efficiency of two kinds of nutritional intervention implemented in hemodialysis patients for 24 weeks (traditional nutritional intervention without a meal served before dialysis for group HG1, and nutritional intervention involving a meal served before dialysis for group HG2), and their impact on nutritional status and serum concentrations of C-reactive protein (CRP). Nutritional status and serum biochemical parameters were analyzed in the control group (CG, n = 70) and in two homogeneous groups of patients, HG1 (n = 35) and HG2 (n = 35). There was an interesting trend in both groups of patients connected with increased intake, mainly of energy and protein. In HG1, the greatest increase in energy intake was observed on Sundays, and in HG2 on the days with dialysis. In HG2, after 24 weeks of the nutritional intervention, an increase in serum albumin (p = 0.0157) and a decrease in CRP concentration (p = 0.0306) were observed, whereas in HG1 there was a decrease in serum albumin concentration (p = 0.0043) with no significant change in CRP concentration. The nutritional intervention applied, called the Malnutrition-Eat Additional Meal (MEAM) diet with an easily digestible meal served before dialysis, was aimed at improving the patients' nutritional status and the obtained results indicate the need not only for substantial reeducation of hemodialysis patients in the area of their diet, but also for undertaking further research and discussions on the possibility of ensuring adequate meals for hemodialysis patients before the dialysis procedure.

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.

Albumin handling in different hemodialysis modalities

Hypoalbuminemia is a major risk factor for morbidity and mortality in dialysis patients. With increasing interest in highly permeable membranes and convective therapies to improve removal of middle molecules, transmembrane albumin loss increases accordingly. Currently, the acceptable upper limit of albumin loss for extracorporeal renal replacement therapies is unknown. In theory, any additional albumin loss should be minimized because it may contribute to hypoalbuminemia and adversely affect the patient's prognosis. However, hypoalbuminemia-associated mortality may be a consequence of inflammation and malnutrition, rather than low albumin levels per se. The purpose of this review is to give an overview of albumin handling with different extracorporeal renal replacement strategies. We conclude that the acceptable upper limit of dialysis-related albumin loss remains unknown. Whether enhanced middle molecule removal outweighs the potential adverse effects of increased albumin loss with novel highly permeable membranes and convective therapies is yet to be determined.

Effectiveness of Intradialytic Parenteral Nutrition in Treating Protein-Energy Wasting in Hemodialysis: A Rapid Systematic Review

Intradialytic parenteral nutrition (IDPN) is commonly requested before recommended therapies in malnourished patients on hemodialysis. This review provides updated critical synthesis of the evidence on the use of IDPN in patients on hemodialysis. We searched MEDLINE, CINAHL, and other sources to identify evidence. Two reviewers sequentially selected studies, abstracted data, rated study quality, and synthesized evidence using predefined criteria. IDPN did not improve clinically relevant outcomes compared with dietary counseling or oral supplementation and had varied results compared with usual care in 12 studies. Data are limited on adverse events or cost-effectiveness of IDPN. Important limitations of the evidence, including limited measurement of clinically important outcomes, methodological concerns, and heterogeneity between studies, weaken our confidence in these findings. IDPN may be a reasonable treatment option for patients who fail to respond or cannot receive recommended treatments, but the broad usage of IDPN before recommended treatment options does not appear warranted.

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.

Use of Intradialytic Parenteral Nutrition in Patients Undergoing Hemodialysis

Intradialytic parenteral nutrition (IDPN) is a form of supplemental nutrition used to treat patients with malnutrition who receive hemodialysis. Once the diagnosis of malnutrition is made in such patients, encouragement of oral intake is the first-line treatment. If this fails, then enteral or parenteral nutrition may be needed. This review examines the literature on the use of IDPN and summarizes the current recommendations. There is considerable controversy over indications and benefits of IDPN, and well-controlled, long-term studies are needed to help tease out these issues. In the interim, clinical judgment should be used when considering IDPN for individual patients.

Pregnancy in Chronic Dialysis: A Review and Analysis of the Literature

Pregnancy is uncommon in end-stage renal failure, particularly in patients requiring dialysis. We reviewed the literature from 1965 to date, seeking an optimal way of dialyzing pregnant women after encountering one such patient.

Methods

We searched the English literature by cross-referencing “pregnancy” with “hemo-” or “peritoneal dialysis” and “renal failure”. Eighty-six pregnancies worldwide were found to which we added one case of our own. Various independent factors were studied against gestational age at delivery using uni- and multivariate analysis. These factors included mother's age, previous delivery, diagnoses of renal disease, dialysis duration prior to pregnancy, gestational age at onset of dialysis, dialysis type, level of hemoglobin during pregnancy, BUN and creatinine targets, BUN/creatinine ratio, dialysis intensity at the beginning and end of pregnancy, influence of erythropoietin and dialysis complications.

Results

Of the 87 pregnancies, 12% resulted in stillbirths, 9% of neonates died prior to discharge. The mean gestational age at delivery was 32 ± 5 weeks, and the mean birth weight 1604 ± 652 g. Two congenital abnormalities and one twin pregnancy were reported. 48% of deliveries were premature. Pre-eclampsia was reported in 11%, and worsening hypertension in 17%. CAPD was used in 25 and hemodialysis in 62 patients. Fetal survival was similar in both cases (72% vs 82%), although incidence of various dialysis complications differed. The conventional dialysis goals of a low target BUN level and hemoglobin for pregnant patients were not factors in predicting fetal outcome. The number of hemodialyses/week were negatively correlated (R = -0.35, P = 0.061), but the hours of dialysis positively correlated (R = 0.42, p = 0.035) to gestational age. Fetal survival was independently influenced by creatinine level [564 µmol/L when baby survived vs 788 µmol/L when baby died (p = 0.021)], BUN/creatinine ratio (50 vs 30, p = 0.053), and hours of dialysis (5.6 hrs vs 3.6 hrs, p=0.013). There was no relation of either frequency or volume of peritoneal dialysis exchanges to gestational age or fetal survival.

Conclusions

Greater attention to a high intake of protein (>1.5 g/kg) and higher dose of hemodialysis, achieved by longer, every other day dialysis, may be the optimal approach to pregnant patients on hemodialysis. Our first attempt to define the goal of hemodialysis is to keep the predialysis creatinine below 600 mmol/L and the protein intake high enough so the predialysis BUN level is >25 mmol/L. There are no clear guidelines on how to best perform CAPD.

When Is Parenteral Nutrition Appropriate?

Parenteral nutrition (PN) represents one of the most notable achievements of modern medicine, serving as a therapeutic modality for all age groups across the healthcare continuum. PN offers a life-sustaining option when intestinal failure prevents adequate oral or enteral nutrition. However, providing nutrients by vein is an expensive form of nutrition support, and serious adverse events can occur. In an effort to provide clinical guidance regarding PN therapy, the Board of Directors of the American Society for Parenteral and Enteral Nutrition (ASPEN) convened a task force to develop consensus recommendations regarding appropriate PN use. The recommendations contained in this document aim to delineate appropriate PN use and promote clinical benefits while minimizing the risks associated with the therapy. These consensus recommendations build on previous ASPEN clinical guidelines and consensus recommendations for PN safety. They are intended to guide evidence-based decisions regarding appropriate PN use for organizations and individual professionals, including physicians, nurses, dietitians, pharmacists, and other clinicians involved in providing PN. They not only support decisions related to initiating and managing PN but also serve as a guide for developing quality monitoring tools for PN and for identifying areas for further research. Finally, the recommendations contained within the document are also designed to inform decisions made by additional stakeholders, such as policy makers and third-party payers, by providing current perspectives regarding the use of PN in a variety of healthcare settings.

Back to the future: restricted protein intake for conservative management of CKD, triple goals of renoprotection, uremia mitigation, and nutritional health

Lowering dietary protein intake (DPI) to approximately 0.6-0.8 g/kgBW/day may be renoprotective through various mechanisms, and it has been recommended in patients with non-dialysis-dependent chronic kidney disease (NDD-CKD) as a means to also control various metabolic consequences of advanced CKD, such as uremic symptoms, hyperparathyroidism, hypertension, hyperkalemia, and hyperphosphatemia. A meta-analysis in this issue of the Journal suggests that low-protein diet is effective and safe when used to retard progression of CKD and alleviate uremic complications. A potential deleterious consequence of lowering DPI in this population is the development or worsening of protein-energy wasting (PEW), which can contribute to poor clinical outcomes such as higher mortality and morbidity. There is currently insufficient high-level evidence to determine the ideal level of DPI in patients with NDD-CKD with high risk of PEW. For the time being we recommend a DPI of 0.6-0.8 g/kgBW/day, and increasing this as needed on an individual basis in patients with PEW. Further examination of this dilemma in randomized controlled clinical trials will be necessary.

A patient with CKD and poor nutritional status

Protein energy wasting is common in patients with CKD and ESRD and is associated with adverse clinical outcomes, such as increased rates of hospitalization and death, in these patients. A multitude of factors can affect the nutritional and metabolic status of patients with CKD, including decreased dietary nutrient intake, catabolic effects of renal replacement therapy, systemic inflammation, metabolic and hormonal derangements, and comorbid conditions (such as diabetes and depression). Unique aspects of CKD also confound reliable assessment of nutritional status, further complicating management of this comorbid condition. In patients in whom preventive measures and oral dietary intake from regular meals cannot help them maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is effective in replenishing protein and energy stores. The advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic steroids and exercise, with nutritional supplementation or alone, improve protein stores and represent potential additional approaches for the treatment of PEW. There are several emerging novel therapies, such as appetite stimulants, anti-inflammatory interventions, and anabolic agents.

Management of protein-energy wasting in non-dialysis-dependent chronic kidney disease: reconciling low protein intake with nutritional therapy

Protein-energy wasting (PEW), characterized by a decline in body protein mass and energy reserves, including muscle and fat wasting and visceral protein pool contraction, is an underappreciated condition in early to moderate stages of chronic kidney disease (CKD) and a strong predictor of adverse outcomes. The prevalence of PEW in early to moderate CKD is ≥20-25% and increases as CKD progresses, in part because of activation of proinflammatory cytokines combined with superimposed hypercatabolic states and declines in appetite. This anorexia leads to inadequate protein and energy intake, which may be reinforced by prescribed dietary restrictions and inadequate monitoring of the patient's nutritional status. Worsening uremia also renders CKD patients vulnerable to potentially deleterious effects of uncontrolled diets, including higher phosphorus and potassium burden. Uremic metabolites, some of which are anorexigenic and many of which are products of protein metabolism, can exert harmful effects, ranging from oxidative stress to endothelial dysfunction, nitric oxide disarrays, renal interstitial fibrosis, sarcopenia, and worsening proteinuria and kidney function. Given such complex pathways, nutritional interventions in CKD, when applied in concert with nonnutritional therapeutic approaches, encompass an array of strategies (such as dietary restrictions and supplementations) aimed at optimizing both patients' biochemical variables and their clinical outcomes. The applicability of many nutritional interventions and their effects on outcomes in patients with CKD with PEW has not been well studied. This article reviews the definitions and pathophysiology of PEW in patients with non-dialysis-dependent CKD, examines the current indications for various dietary modification strategies in patients with CKD (eg, manufactured protein-based supplements, amino acids and their keto acid or hydroxyacid analogues), discusses the rationale behind their potential use in patients with PEW, and highlights areas in need of further research.

Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism

Protein energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with adverse clinical outcomes, especially in individuals receiving maintenance dialysis therapy. A multitude of factors can affect the nutritional and metabolic status of CKD patients requiring a combination of therapeutic maneuvers to prevent or reverse protein and energy depletion. These include optimizing dietary nutrient intake, appropriate treatment of metabolic disturbances such as metabolic acidosis, systemic inflammation, and hormonal deficiencies, and prescribing optimized dialytic regimens. In patients where oral dietary intake from regular meals cannot maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is shown to be effective in replenishing protein and energy stores. In clinical practice, the advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic strategies such as anabolic steroids, growth hormone, and exercise, in combination with nutritional supplementation or alone, have been shown to improve protein stores and represent potential additional approaches for the treatment of PEW. Appetite stimulants, anti-inflammatory interventions, and newer anabolic agents are emerging as novel therapies. While numerous epidemiological data suggest that an improvement in biomarkers of nutritional status is associated with improved survival, there are no large randomized clinical trials that have tested the effectiveness of nutritional interventions on mortality and morbidity.

[Efficacy of oral supplementation during dialysis in patients with chronic renal failure]

Protein-calorie malnutrition is common in hemodialysis patients and is a powerful predictor of morbidity and mortality. Nutritional supplementation, administered orally or parenterally, especially during dialysis, may compensate for the relatively inadequate protein and energy intake and improves net protein anabolism in chronic hemodialysis patients. Intradialytic oral nutrition seems preferable to intradialytic parenteral nutrition (IDPN) due to its lower cost and persistence of its anabolic effects after infusion is stopped, and because IDPN induces a higher increase in serum glucose and insulin levels and a greater reduction in serum ghrelin concentrations. Further larger scale randomized, controlled trials of nutritional interventions should be performed in maintenance dialysis patients to assess their efficacy regarding quality of life, morbidity, and mortality.

Severity of hypoalbuminemia predicts response to intradialytic parenteral nutrition in hemodialysis patients

BACKGROUND

Intradialytic parenteral nutrition (IDPN) is used infrequently to correct hypoalbuminemia in maintenance hemodialysis (MHD) patients. We hypothesized that the severity of baseline hypoalbuminemia correlates with the success rate of IDPN therapy in MHD patients.

METHODS

In a prospective and contemporary cohort of 196 hypoalbuminemic MHD patients who received IDPN through Pentec Health (Boothwyn, PA), predictors of IDPN response were examined using multivariate logistic regression.

RESULTS

Of 196 hypoalbuminemic MHD patients, 134 had severe hypoalbuminemia, defined as a baseline serum albumin level of less than 3.0 g/dL. The average period of IDPN therapy was 5.8 +/- 2.4 months, S.D. The baseline level of serum albumin was lower in MHD patients who responded to IDPN (2.68 +/- 0.47 g/dL, S.D.). A multivariate logistic regression analysis adjusted the associations for age, gender, diabetes, and IDPN time. The presence of severe hypoalbuminemia (serum albumin, <3.0 g/dL) at baseline was associated with a 2.5 times higher chance of responding to IDPN (95% confidence interval, 1.3 to 4.9; P = .006). The same severe hypoalbuminemia was associated with a 3.5 times increased likelihood of serum albumin correction by at least 0.5 g/dL (95% confidence interval, 1.8 to 6.8; P < .001).

CONCLUSIONS

Improvement of hypoalbuminemia occurs in most hypoalbuminemic MHD patients who receive IDPN therapy. The likelihood and magnitude of the response to IDPN are associated with the severity of baseline hypoalbuminemia. These associations need to be verified in controlled trials.

Nutrition support for the chronically wasted or acutely catabolic chronic kidney disease patient

Because of the number of factors affecting the nutritional and metabolic status in patients with advanced chronic kidney disease or who are on maintenance dialysis, the prevention and treatment of protein-energy wasting (PEW) of chronic kidney disease should involve a comprehensive combination of maneuvers to diminish protein and energy depletion, in addition to therapies that will avoid further losses. The available evidence suggests that nutritional supplementation, administered orally or parenterally, is effective in the treatment of maintenance dialysis patients with PEW in whom oral dietary intake from regular meals cannot maintain adequate nutritional status. Increased oral nutrient intake during dialysis and at home is the ideal choice for this intervention. In clinical practice, the advantages of intradialytic oral nutritional supplements include proven efficacy and compliance. Therefore, at a minimum, oral nutritional supplementation given intradialytically should be attempted in maintenance dialysis patients with PEW, accompanied by individualized dietary advice for appropriate intake at home. In ones who cannot tolerate oral feeding, other forms of nutritional supplementation including intradialytic parenteral nutritional are a reasonable strategy. Although not proven conclusively, nutritional interventions in the form of supplementation may lead to considerable improvements in mortality, hospitalization, and treatment costs.

Intradialytic nutritional support

PURPOSE OF REVIEW

Intradialytic nutritional support has been used for more than 30 years both in critically ill patients with acute renal failure and during maintenance hemodialysis. Present knowledge allows better estimation of its metabolic and nutritional efficacy, as well its effect on patient outcome.

RECENT FINDINGS

Recent data showed that intradialytic nutritional support is able to counteract these effects of dialysis on protein metabolism and to improve both nitrogen and energy balance. In maintenance hemodialysis patients, the improvement of nutritional status during nutritional support was shown to improve long-term survival. In critically ill patients with acute renal failure, protein sparing is one of the main therapeutic goals. The effect of nutritional support on patient outcome is not demonstrated. Recent data, however, showed that the improvement of nitrogen balance may be associated with a better outcome.

SUMMARY

Current information helps to better assess the effects of intradialytic nutritional support, to clarify the nutritional management of renal failure patients and to provide recommendations. Future research should focus on the possible means to improve the efficacy of nutritional support, either by modifying its components of by associating anabolic or anticatabolic agents.

Intradialytic parenteral nutrition does not improve survival in malnourished hemodialysis patients: a 2-year multicenter, prospective, randomized study

Although intradialytic parenteral nutrition (IDPN) is a method used widely to combat protein-calorie malnutrition in hemodialysis patients, its effect on survival has not been thoroughly studied. We conducted a prospective, randomized trial in which 186 malnourished hemodialysis patients received oral nutritional supplements with or without 1 year of IDPN. IDPN did not improve 2-year mortality (primary end point), hospitalization rate, Karnofsky score, body mass index, or laboratory markers of nutritional status. Instead, both groups demonstrated improvement in body mass index and the nutritional parameters serum albumin and prealbumin (P < 0.05). Multivariate analysis showed that an increase in prealbumin of >30 mg/L within 3 months, a marker of nutritional improvement, independently predicted a 54% decrease in 2-year mortality, as well as reduced hospitalizations and improved general well-being as measured by the Karnofsky score. Therefore, although we found no definite advantage of adding IDPN to oral nutritional supplementation, this is the first prospective study demonstrating that an improvement in prealbumin during nutritional therapy is associated with a decrease in morbidity and mortality in malnourished hemodialysis patients.

Intradialytic parenteral nutrition: comparison of olive oil versus soybean oilbasedlipid emulsions

Lipid, oxidative and inflammatory parameters are frequently altered in dialysis patients and may be worsened by intravenous lipid emulsions (ILE). We assessed the efficacy and tolerance of olive as compared with standard soybean oil-based ILE during intradialytic parenteral nutrition (IDPN). IDPN mixtures containing amino acids, glucose, and either olive oil (OO group,n17) or soybean oil-based ILE (SO group,n18) were administered in a 5-week randomized, double-blind study. On days 0 and 35, patients' nutritional status was assessed by BMI, normalized protein catabolic rate, predialytic creatinine, serum albumin and transthyretin; lipid metabolism by plasma LDL- and HDL-cholesterol, triacylglycerols, phospholipids, apo A-I, A-II, B, C-II, C-III, E and lipoprotein (a); oxidative status by α-tocopherol, retinol, selenium, glutathione peroxidase, malondialdehyde and advanced oxidized protein products; inflammatory status by serum C-reactive protein, orosomucoid, IL-2 and IL-6. No serious adverse event was observed. Significant changes were observed from day 0 to day 35 (P<0·05): nutritional criteria improved (albumin in OO; albumin, transthyretin and creatinine in SO); LDL-cholesterol, apo B, C-II, C-III and apo A-I/A-II ratio increased in both groups. HDL-cholesterol decreased in OO; apo E increased and lipoprotein (a) decreased in SO; α-tocopherol/cholesterol ratio increased in OO; malondialdehyde decreased in both groups; IL-2 increased in both groups. The between-group comparison only showed the following differences: α-tocopherol/cholesterol increased in OO; lipoprotein (a) decreased in SO. From these data, it was concluded that OO- and SO-based IDPNs similarly improved nutritional status and influenced plasma lipid, oxidative, inflammatory and immune parameters.

Nutritional Supplementation in Adult Patients on Hemodialysis

At the beginning of the 1980s, nutritional status appeared as a key element of quality of life, health care requirements, and survival during chronic renal failure. In patients on dialysis, malnutrition is a major determinant of survival, and its management appears to be a key element in terms of outcome. Recommendations for the nutritional management of patients on hemodialysis have been elaborated by the National Kidney Foundation (NKF) and the European Society of Parenteral and Enteral Nutrition (ESPEN).

Nutrition and Metabolism in Kidney Disease

Nutritional and metabolic derangements are highly prevalent in patients with chronic kidney disease (CKD) and patients on renal replacement therapy. These derangements, which can be termed uremic malnutrition, significantly affect the high morbidity and mortality rates observed in this patient population. Uremic malnutrition clearly is related to multiple factors encountered during the predialysis stage and during chronic dialysis therapy. Several preliminary studies suggested that interventions to improve the nutritional status and metabolic status of uremic patients actually may improve the expected outcome in these patients, although their long-term efficacy is not well established. It therefore is important to emphasize that uremic malnutrition is a major comorbid condition in CKD and renal replacement therapy patients, and that all efforts should be made to try to understand better and treat these conditions effectively to improve not only mortality but also the quality of life of chronically uremic patients. In this article we review the current state of knowledge in the field of nutrition and metabolism in all stages of CKD and renal replacement therapy, including kidney transplant. We also address questions that face investigators in this field and suggest where future research might be headed.

Muscle Protein Metabolism During Hemodialysis

Despite improvement in many aspects of the care of maintenance hemodialysis (HD) patients, protein-calorie malnutrition, which is characterized by an insidious loss of somatic protein, is common and is a major risk factor for increased morbidity and mortality. We present here an overview of the current knowledge on protein metabolism in uremic patients with the expectation of providing insights into the mechanisms involved in HD-associated catabolism and outlining the rationale underlying intradialytic nutrition. We concentrate on the discussion of muscle protein metabolism because muscle is the predominant site of protein storage, and its integrity is mandatory for the maintenance of a good quality of life.

Malnutrition in Hemodialysis Patients: What Therapy?

Malnutrition is common in hemodialysis patients and is a powerful predictor of morbidity and mortality. Although much progress has been made in recent years in identifying the causes and pathogenesis of malnutrition in hemodialysis patients, as well as recognizing the link between malnutrition and morbidity and mortality, no consensus has been reached concerning its management. Along with such conventional interventions as nutritional counseling, oral nutritional supplements, and intradialytic parenteral nutrition, novel preventive and therapeutic strategies have been tested, such as appetite stimulants, growth hormone, androgenic anabolic steroids, and anti-inflammatory drugs, with contradictory and nonconclusive results. Malnutrition still remains a great challenge for nephrologists in the third millennium.

Multinutrient Oral Supplements and Tube Feeding in Maintenance Dialysis: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review aims to determine the potential benefits of enteral multinutrient support (oral or tube) in patients with chronic kidney disease (CKD) receiving maintenance dialysis.

METHODS

Studies of multinutrient oral supplements and enteral tube feeding that involved comparisons of nutritional support versus routine care (ie, usual diet), disease-specific formulae (with adapted macronutrient and micronutrient composition for use in maintenance dialysis patients) versus standard formulae, and enteral tube feeding versus parenteral nutrition are included in this review. The outcome measures sought were clinical (quality of life, complications, and mortality), biochemical (albumin and electrolyte levels), and nutritional (dietary intake and anthropometry). Meta-analyses were performed when possible.

RESULTS

This review of 18 studies (5 randomized controlled trials [RCTs], 13 non-RCTs) suggests that enteral nutritional support increased total (energy and protein) intake and increased serum albumin concentration by 0.23 g/dL (2.3 g/L; 95% confidence interval, 0.037 to 0.418 g/dL [0.37 to 4.18 g/L]; 1 RCT, 2 non-RCTs), with little effect on electrolyte status (serum phosphate and potassium). Few studies reported clinical outcome, and there was insufficient information to compare disease-specific versus standard formulae or enteral versus parenteral nutrition.

CONCLUSION

This systematic review suggests that enteral multinutrient support significantly increases serum albumin concentrations and improves total dietary intake. This may improve clinical outcome, especially in malnourished patients, but insufficient published data exist to examine this. Additional research is required to investigate clinical, economic, and nutritional consequences of using oral supplements and tube feeding (using standard or disease-specific feeds) in patients with CKD receiving maintenance dialysis.

C-reactive protein and end-stage renal disease

The significance of CRP and inflammation has increased over time, especially in the end-stage renal disease (ESRD) population. From a simple marker it now appears that CRP is an active participant in pro-atherosclerotic phenomenon including local pro-inflammatory and thrombotic events. Studies in the general population indicate the usefulness of CRP in prognostication and in monitoring response to therapy. The clinical usefulness of CRP monitoring in chronic kidney disease (CKD) and especially in ESRD deserves closer study. In the meantime, the utility of CRP measurements for monitoring and treatment is on a case-by-case basis. Management of traditional cardiovascular risk factors should be considered. In the interest of optimizing therapy it is prudent to use biocompatible membranes and ultrapure water. A careful search for infectious processes in dialysis patients is recommended, with special attention to vascular access sites, periodontitis, gastritis, and other potentially chronic or covert infections. ACE-inhibitor use should be maximized in all eligible CKD patients. The data on the use of statins in ESRD have been generally positive but await further validation. Individualized use for selected patients is probably beneficial.

Protein and energy: recommended intake and nutrient supplementation in chronic dialysis patients

Nutritional status is an important predictor of clinical outcome in end-stage renal disease (ESRD) patients, especially in patients on chronic hemodialysis. Uremic malnutrition is strongly associated with increased risk of death and hospitalization events in this patient population, and decreased muscle mass is the most significant predictor of these outcomes. Several factors that influence protein metabolism predispose chronic hemodialysis patients to increased catabolism and loss of lean body mass. The available evidence suggests that low protein and energy intake associated with advanced uremia along with catabolic consequences of dialytic therapies can lead to the development of uremic malnutrition. Recent studies show that the hemodialysis procedure induces a net protein catabolic state at the whole-body level as well as skeletal muscle. There is evidence to suggest that these undesirable effects are due to decreased protein synthesis and increased proteolysis. Provision of nutrients, either in the form of intradialytic parenteral nutrition or oral feeding during hemodialysis, can adequately compensate for the catabolic effects of the hemodialysis procedure. While the mechanisms of these effects are not studied in detail, changes in extracellular amino acid concentrations, along with certain anabolic hormones such as insulin, are important mediators of these actions.