Intradialytic parenteral nutrition in malnourished hemodialysis patients: a prospective long-term study

Nutrition Management in Geriatric Patients with CKD

Sarcopenia, defined as age-related decline in skeletal muscle mass and functional capacity, is a hallmark nutritional abnormality observed in patients with moderate-to-advanced CKD. Uremic state and associated medical conditions also predispose older patients with CKD to protein-energy wasting, a nutritional abnormality that could include sarcopenia. Prevention of protein and energy depletion and replenishing the already low nutritional reserves elderly patients with CKD should focus on conventional and innovative strategies. This review aims to provide an overview of the mainstay of nutritional therapy in this patient population, such as intake of adequate amounts of protein and energy along with preserving fluid, electrolyte, and mineral balance, and to discuss more innovative interventions to aid these approaches.

Nutritional status improvement in elderly CKD patients: a systematic review

PURPOSE

Almost all CKD patients have a poor nutritional status, while elderly CKD patients are specifically frail and malnourished. Our aim is to conduct a systematic review of the up to date primary studies that look at methods of improving nutritional status in CKD patients in the elderly demographic.

METHODS

A focussed and sensitive search strategy was applied to the PUBMED database to identify relevant English language articles. Once articles were identified a detailed quality and bias assessment was performed. Two independent researchers (MZ and SM) then subsequently carried out detailed data extraction and analysis and this was subsequently verified by a third researcher (IN).

RESULTS

A total of 19 studies were included in our systematic review which included 7 non-randomised control trials and 15 randomised controlled trials. The outcomes that we considered to be most relevant for our subject title were: mortality data, SGA, albumin, total protein, isoleucine, leucine, prealbumin, transferrin, leptin, valine, TAG, HDL, LDL and total amino acids. Detailed bias analysis of the different studies was also conducted.

CONCLUSION

This is the first systematic review of the literature, so far, on the subject, involving elderly CKD patients. The quality of trials is low, very heterogenic in patients, methods and outcomes. However, we found a positive effect of dietary interventions on the nutritional status of most patients studied, highlighted by improvement in serum albumin and SGA, the most measured outcomes.

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.

Could intradialytic nutrition improve refractory anaemia in patients undergoing haemodialysis?

BACKGROUND

This prospective randomised study was designed to evaluate the efficacy of intradialytic parenteral nutrition (IDPN) therapy in malnourished patients with refractory anaemia.

METHODS

Forty patients who were malnourished with a BMI not greater than 23 (17-23) kg/m² , undergoing regular HD were included. Of those, 20 patients received 500-1000 ml of IDPN at a rate of 250-300 ml/h at each HD session three days per week for six consecutive months. The other 20 patients did not receive IDPN infusion. The malnutrition inflammation score (MIS) and haematological parameters were recorded at baseline and after three and six months.

RESULTS

Mean haemoglobin levels, BMI and serum albumin were significantly increased while MIS was significantly decreased after the 3rd and 6th months of IDPN.

CONCLUSION

IDPN has a good role in improving refractory anaemia by significantly increasing haemoglobin levels, body weight, and serum albumin levels. The intervention also significantly decreases the MIS of patients.

Malnutrition in Dialysis Patients--The Need for Intervention Despite Uncertain Benefits

We are in the midst of an epidemic of overnutrition which has resulted in a widespread increase in obesity rates in modern societies. Yet for patients suffering from serious chronic illnesses such as end stage renal disease (ESRD), malnutrition (encompassing both inadequate quantity and quality of nutrient intake) represents a far more significant danger. Protein-energy wasting has been identified as one of the strongest risk factor for adverse outcomes in ESRD patients, and modeling studies have suggested that improving nutrition could result in substantial lowering of mortality rates and other benefits. To date there is ample evidence that various interventions can have a positive impact on the nutritional status of ESRD patients, yet we still lack randomized controlled clinical trials showing that the same interventions could indeed lead to better survival or other clinical benefits. This knowledge gap, which is all too common for clinical problems encountered in nephrology, should not act as a deterrent, but it should rather incentivize us to continue exploring novel interventions aimed at improving malnutrition in ESRD.

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.

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.

The effect of resistance exercise to augment long-term benefits of intradialytic oral nutritional supplementation in chronic hemodialysis patients

BACKGROUND

Resistance exercise combined with intradialytic oral nutrition (IDON) supplementation improves net protein balance in the acute setting in chronic hemodialysis patients. We hypothesized that combination of long-term resistance exercise and IDON would improve markers of muscle mass and strength further compared with IDON alone.

METHODS

Thirty-two participants (21 male; mean age, 43 ± 13 years) on chronic hemodialysis were randomly assigned to IDON plus resistance exercise (NS + EX), or IDON (NS) alone for 6 months. IDON consisted of a lactose-free formula consisting of protein, carbohydrate, and fat. Three sets of 12 repetitions of leg-press were completed before each dialysis session in the NS + EX arm. Primary outcome measurement was lean body mass. Muscle strength and other nutritional parameters were measured as secondary outcomes.

RESULTS

Of 32 participants, 22 completed the 6-month intervention. There were no statistically significant differences between the study interventions with respect to changes in lean body mass and body weight, when comparing NS + EX to NS. There were also no statistically significant differences in any of the secondary outcomes measured in the study. Body weight (80.3 ± 16.6 kg, 81.1 ± 17.5 kg, and 80.9 ± 18.2 kg at baseline, month 3, and month 6, respectively; P = .02) and 1-repetition maximum (468 ± 148 lb, 535 ± 144 lb, and 552 ± 142 lb, respectively; P = .001) increased statistically significantly during the study for all patients combined.

CONCLUSION

This study did not show further benefits of additional resistance exercise on long-term somatic protein accretion above and beyond nutritional supplementation alone. When both treatments groups were combined, body weight and muscle strength improved during the study.

Relationship between serum protein and mortality in adults on long-term hemodialysis: exhaustive review and meta-analysis

The aim of this exhaustive review and meta-analysis was to explore the relation among serum protein, inflammatory markers, and all-cause and cardiovascular mortalities in adult patients on maintenance hemodialysis. We searched the Medline, Science Citation Index, Academic Search Premier, Cochrane Library, and Embase electronic data bases. Data extraction and quality assessment were done independently by two reviewers and results were pooled using the random effects model. Cochran's Q was used to identify heterogeneity and a funnel plot was used for assessment of publication bias. A meta-analysis was performed on 38 studies (265 330 patients) reporting on serum proteins, inflammatory markers, and mortality. A significant inverse relation was found between serum albumin and all-cause (hazard ratio [HR] 0.7038, 95% confidence interval [CI] 0.6367-0.7781) and cardiovascular (HR 0.8726, 95% CI 0.7909-0.9628) mortalities, with a significantly stronger relation with all-cause mortality (P=0.0014). Pooled results for C-reactive protein showed a weak but significant direct relation with all-cause mortality (HR 1.0322, 95% CI 1.0151-1.0496), but there was not a significant relation between C-reactive protein and cardiovascular mortality (HR 1.0172, 95% CI 0.9726-1.0639). A high degree of heterogeneity was identified among studies especially in the case of all-cause mortality. An asymmetrical funnel plot for serum albumin is suggestive of publication bias. From the meta-analysis it is concluded that serum albumin showed a significant inverse relation with all-cause and cardiovascular mortalities but the relation between prealbumin and all-cause mortality was not significant. C-reactive protein showed a significant direct relation with all-cause mortality but not with cardiovascular mortality. The potential adverse effects of malnutrition and infections in relation to mortality highlight the need for continued treatment of infections and correction of malnutrition in patients on dialysis.

New insights into the role of anabolic interventions in dialysis patients with protein energy wasting

PURPOSE OF REVIEW

Patients on maintenance dialysis commonly develop protein-energy wasting (PEW), which is associated with poor survival. There have been several advances in anabolic interventions aimed at improving PEW in these patients in recent years.

RECENT FINDINGS

Oral or parenteral nutritional supplementation, especially if administered during dialysis, improves net protein anabolism in chronic hemodialysis patients. These beneficial effects have been extended to long-term benefits in recent clinical trials. Resistance exercise, alone or combined with intradialytic oral nutrition supplementation, also improves net protein balance in the acute setting although recent studies indicated a limited beneficial effect of long-term exercise alone on muscle protein accretion in chronic hemodialysis patients. Anabolic agents such as growth hormone and androgens have been shown to exert significant benefits on visceral protein stores, muscle mass and strength. Ghrelin, a hormone with combined orexigenic and anti-inflammatory effects, is a potential new nutritional intervention in maintenance dialysis patients.

SUMMARY

Existing anabolic therapeutic strategies have proven to be effective in improving PEW in maintenance dialysis patients. Combined anabolic interventions and several new and established anabolic hormones represent further promising nutritional interventions. Large-scale randomized controlled trials examining the effects of anabolic interventions on mortality and morbidity are still lacking.

Effects of peridialytic oral supplements on nutritional status and quality of life in chronic hemodialysis patients

OBJECTIVE

Our objective was to determine the effects of peridialytic oral supplements on nutritional markers and quality of life (QOL) in patients receiving maintenance hemodialysis.

DESIGN

This trial was open, prospective, nonrandomized, and comparative.

SETTING

This study was performed at an outpatient hemodialysis unit in a teaching hospital.

PATIENTS

This study included 88 adults with chronic kidney disease at stage 5.

INTERVENTION

This study involved directly observed nutrition therapy with >or=1 can of enteral nutrition (Nepro) with each hemodialysis session thrice weekly for 3 months, or standard care.

MAIN OUTCOME MEASURE

Changes in biochemical markers of nutritional status and QOL, as measured by the Kidney Disease Quality of Life-Short Form, were determined.

RESULTS

Peridialytic oral nutrition resulted in a significant difference between the nutrition and comparison groups in serum albumin change over time (P = .03; repeated-measures analysis of variance with covariates). Mean (+/-SD) serum albumin concentration did not differ between baseline and month 3 in the nutrition group (3.68 +/- 0.33 g/dL vs. 3.75 +/- 0.40 g/dL; P = .12), but in the comparison group, serum albumin levels declined significantly (3.93 +/- 0.34 g/dL at baseline versus 3.81 +/- 0.37 g/dL at month 3; P = .04). The "role-physical" domain score of the Kidney Disease Quality of Life-Short Form significantly changed over time in the nutrition group versus the comparison group (P = .02; repeated-measures analysis of variance with covariates). Nepro was well-tolerated, and greater than 80% of the prescribed therapy was consumed.

CONCLUSION

Oral nutrition, as part of structured, directly observed peridialytic therapy in chronic hemodialysis patients, was well-accepted, and resulted in the maintenance of serum albumin levels and QOL with respect to impact of physical health on daily activities. These findings need to be confirmed in a randomized, controlled trial.

ESPEN Guidelines on Parenteral Nutrition: surgery

In modern surgical practice it is advisable to manage patients within an enhanced recovery protocol and thereby have them eating normal food within 1-3 days. Consequently, there is little room for routine perioperative artificial nutrition. Only a minority of patients may benefit from such therapy. These are predominantly patients who are at risk of developing complications after surgery. The main goals of perioperative nutritional support are to minimize negative protein balance by avoiding starvation, with the purpose of maintaining muscle, immune, and cognitive function and to enhance postoperative recovery. Several studies have demonstrated that 7-10 days of preoperative parenteral nutrition improves postoperative outcome in patients with severe undernutrition who cannot be adequately orally or enterally fed. Conversely, its use in well-nourished or mildly undernourished patients is associated with either no benefit or with increased morbidity. Postoperative parenteral nutrition is recommended in patients who cannot meet their caloric requirements within 7-10 days orally or enterally. In patients who require postoperative artificial nutrition, enteral feeding or a combination of enteral and supplementary parenteral feeding is the first choice. The main consideration when administering fat and carbohydrates in parenteral nutrition is not to overfeed the patient. The commonly used formula of 25 kcal/kg ideal body weight furnishes an approximate estimate of daily energy expenditure and requirements. Under conditions of severe stress requirements may approach 30 kcal/kg ideal body weights. In those patients who are unable to be fed via the enteral route after surgery, and in whom total or near total parenteral nutrition is required, a full range of vitamins and trace elements should be supplemented on a daily basis.

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.

Association of serum prealbumin and its changes over time with clinical outcomes and survival in patients receiving hemodialysis

BACKGROUND

In patients receiving maintenance hemodialysis (MHD), a low serum prealbumin is an indicator of protein-energy wasting.

OBJECTIVE

We hypothesized that baseline serum prealbumin correlates independently with health-related quality of life (QoL) and death and that its change over time is a robust mortality predictor.

DESIGN

Associations and survival predictability of serum prealbumin at baseline and its changes over 6 mo were examined in a 5-y (2001-2006) cohort of 798 patients receiving MHD.

RESULTS

Patients with serum prealbumin >or= 40 mg/dL had greater mid-arm muscle circumference but lower percentage of total body fat. Both serum interleukin-6 and dietary protein intake correlated independently with serum prealbumin. Measures of QoL indicated better physical health, physical function, and functionality with higher prealbumin concentrations. Although baseline prealbumin was not superior to albumin in predicting survival, in both all and normoalbuminemic (albumin >or= 3.5 g/dL; n = 655) patients, prealbumin < 20 mg/dL was associated with higher death risk in adjusted models, but further adjustments for inflammatory cytokines mitigated the associations. In 412 patients with baseline prealbumin between 20 and 40 mg/dL whose serum prealbumin was remeasured after 6 mo, a >or=10-mg/dL fall resulted in a death hazard ratio of 1.37 (95% CI: 1.02, 1.85; P = 0.03) after adjustment for baseline measures, including inflammatory markers.

CONCLUSIONS

Even though baseline serum prealbumin may not be superior to albumin in predicting mortality in MHD patients, prealbumin concentrations <20 mg/dL are associated with death risk even in normoalbuminemic patients, and a fall in serum prealbumin over 6 mo is independently associated with increased death risk.

Nutrition, inflammation and chronic kidney disease

PURPOSE OF REVIEW

Protein-energy wasting and chronic inflammation are important comorbid conditions that predict poor clinical outcome in patients with advanced chronic kidney disease. The current article aims to provide a brief overview of the etiology and nutritional consequences of chronic inflammation with an outline of potential treatment options.

RECENT FINDINGS

The exact mechanisms leading to these unfavorable conditions are not fully elucidated and are most likely multifactorial. Irrespective of the specific etiologic mechanisms, it appears that the common pathway for all the metabolic derangements is related to exaggerated protein degradation relative to protein synthesis. Several studies suggest that chronic inflammation can predispose advanced chronic kidney disease patients to a catabolic state leading to worsening of protein-energy wasting by both increasing protein breakdown and decreasing protein synthesis. Chronic administration of nutritional supplementation, both parenterally and orally, improves nutritional status even in inflamed hemodialysis patients. Several pilot studies indicate that antiinflammatory intervention can also improve the metabolic and nutritional profiles.

SUMMARY

While a single common etiology has not been identified in this complex process, nutritional and antiinflammatory interventions can provide potential treatment options to improve the high mortality and morbidity in patients with advanced chronic kidney disease.

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.

Nutrition support and the chronic critical illness syndrome

Critical illness can be viewed as consisting of 4 distinct stages: (1) acute critical illness (ACI), (2) prolonged acute critical illness, (3) chronic critical illness, and (4) recovery. ACI represents the evolutionarily programmed response to a stressor. In ACI, substrate is shunted away from anabolism and toward vital organ support and inflammatory proteins. Nutrition support in this stage is unproven and may ultimately prove detrimental. As critical illness progresses, there is no evolutionary precedent, and man owes his life to modern critical care medicine. It is at this point that nutrition and metabolic support become integral to the care of the patient. This paper (1) delineates and develops the 4 stages of critical illness using current evidence, clinical experience, and new hypotheses; (2) defines the chronic critical illness syndrome (CCIS); and (3) details an approach to the metabolic and nutrition support of the chronically critically ill patient using the metabolic model of critical illness as a guide. It is our hope that this clinical model can generate testable hypotheses that can improve the outcome of this unique population of patients.

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.

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.

Assessment of nutritional status in hemodialysis patients using patient-generated subjective global assessment

OBJECTIVE

To evaluate the scored Patient-Generated Subjective Global Assessment (PG-SGA) as a nutrition assessment tool in hemodialysis patients.

DESIGN

A cross-sectional observational study assessing the nutritional status of hemodialysis patients.

SETTING

Private tertiary Australian hospital.

SUBJECTS

Sixty patients, ages 63.9 +/- 16.2 years.

INTERVENTION

Scored PG-SGA questionnaire, comparison of PG-SGA score > or =9 with subjective global assessment (SGA), albumin, corrected arm muscle area, and triceps skinfold.

RESULTS

According to SGA, 80% of patients were well nourished and 20% of patients were malnourished. Patients classified as well nourished (SGA-A) attained a significantly lower median PG-SGA score compared with those rated as moderately malnourished or at risk of malnutrition (SGA-B). A PG-SGA score > or =9 had a sensitivity of 83% and a specificity of 92% at predicting SGA classification. There were significant correlations between the PG-SGA score and serum albumin, PG-SGA score, and percentage weight loss over the past 6 months. There was no association between PG-SGA score and body mass index or anthropometric measurements.

CONCLUSION

The scored PG-SGA is an easy-to-use nutrition assessment tool that allows quick identification of malnutrition in hemodialysis patients.

Malnutrition in Patients Undergoing Hemodialysis: Is Intradialytic Parenteral Nutrition the Answer?

Patients with end-stage renal disease often experience malnutrition as a result of decreased dietary intake; inadequate dialysis; loss of nutrients into the dialysate; abnormal protein, carbohydrate, and lipid metabolism; and concomitant diseases, which may contribute to an increase in morbidity and mortality. Intradialytic parenteral nutrition (IDPN) is being used to improve nutritional status, in conjunction with other methods of nutritional supplementation. The biggest advantage of IDPN is probably its convenience since it is administered during dialysis treatment and thus does not require additional clinic visits or prolonged dialysis time. Although IDPN has several disadvantages, its ability to improve nutritional status and reduce morbidity and mortality in patients with end-stage renal disease is promising. Well-designed, large-scale, prospective studies are required to confirm its beneficial effects.

Malnutrition-inflammation complex syndrome in dialysis patients: causes and consequences

Protein-energy malnutrition (PEM) and inflammation are common and usually concurrent in maintenance dialysis patients. Many factors that appear to lead to these 2 conditions overlap, as do assessment tools and such criteria for detecting them as hypoalbuminemia. Both these conditions are related to poor dialysis outcome. Low appetite and a hypercatabolic state are among common features. PEM in dialysis patients has been suggested to be secondary to inflammation; however, the evidence is not conclusive, and an equicausal status or even opposite causal direction is possible. Hence, malnutrition-inflammation complex syndrome (MICS) is an appropriate term. Possible causes of MICS include comorbid illnesses, oxidative and carbonyl stress, nutrient loss through dialysis, anorexia and low nutrient intake, uremic toxins, decreased clearance of inflammatory cytokines, volume overload, and dialysis-related factors. MICS is believed to be the main cause of erythropoietin hyporesponsiveness, high rate of cardiovascular atherosclerotic disease, decreased quality of life, and increased mortality and hospitalization in dialysis patients. Because MICS leads to a low body mass index, hypocholesterolemia, hypocreatininemia, and hypohomocysteinemia, a "reverse epidemiology" of cardiovascular risks can occur in dialysis patients. Therefore, obesity, hypercholesterolemia, and increased blood levels of creatinine and homocysteine appear to be protective and paradoxically associated with a better outcome. There is no consensus about how to determine the degree of severity of MICS or how to manage it. Several diagnostic tools and treatment modalities are discussed. Successful management of MICS may ameliorate the cardiovascular epidemic and poor outcome in dialysis patients. Clinical trials focusing on MICS and its possible causes and consequences are urgently required to improve poor clinical outcome in dialysis patients.

Role of nutrition for cardiovascular risk reduction in chronic kidney disease patients

Cardiovascular disease (CVD) is the major cause of death in end-stage renal disease (ESRD) patients. Uremic malnutrition and chronic inflammation are important comorbid conditions, closely associated with CVD risk in ESRD patients. A pathophysiologic link between uremic malnutrition, chronic inflammation, and atherosclerosis has been proposed in this patient population. Uremic malnutrition can result from chronic inflammation and can accelerate the progression of cardiovascular disease. Chronic inflammation can also directly predispose ESRD patients to a proatherogenic state. Both uremic malnutrition and chronic inflammation are also associated with increased oxidative stress, a condition proposed as a unifying concept of CVD in uremia. Although a single common etiology has not been identified in this complex process, nutritional, anti-inflammatory, and antioxidant interventions can provide potential treatment options to improve the high mortality and morbidity in ESRD patients.

Protein homeostasis in chronic hemodialysis patients

PURPOSE OF REVIEW

Nutritional status is an important predictor of clinical outcome in chronic hemodialysis patients, as uremic malnutrition is strongly associated with an increased risk of death and hospitalization events. Decreased muscle mass is the most significant predictor of morbidity and mortality in these patients. Several factors that influence protein metabolism predispose chronic hemodialysis patients to increased catabolism and the loss of lean body mass. The purpose of this review is to discuss recent advances in the understanding of abnormalities in protein homeostasis in chronic hemodialysis patients.

RECENT FINDINGS

It has long been suspected that the hemodialysis procedure is a net catabolic event. Recent studies have indeed shown that the hemodialysis procedure induces a net protein catabolic state at the whole-body level as well as in skeletal muscle. There is evidence to suggest that these undesirable effects are caused by decreased protein synthesis and increased proteolysis. The provision of nutrients, either in the form of intradialytic parenteral nutrition or oral feeding during hemodialysis, can adequately compensate the catabolic effects of the hemodialysis procedure. Whereas the mechanisms of these effects have not been studied in detail, changes in extracellular amino acid concentrations and certain anabolic hormones such as insulin are important mediators of these actions.

SUMMARY

There is now indisputable evidence to suggest that the hemodialysis procedure leads to a highly catabolic state. Despite this, chronic hemodialysis patients can still achieve anabolism when given adequate protein supplementation to meet the metabolic requirements of hemodialysis, and when adequate insulin is present.

Uremic malnutrition: new insights into an old problem

Uremic malnutrition is highly prevalent and is associated with poor clinical outcomes in end-stage renal disease (ESRD) patients. Inadequate diet and a state of persistent catabolism play major roles in predisposing these patients to uremic malnutrition and appear to have an additive effect on overall outcome. Recent studies highlight the existence of a complex syndrome involving chronic inflammation, metabolic abnormalities, and hormonal derangements contributing to the increased morbidity and mortality observed in ESRD patients. Novel strategies such as appetite stimulants, anti-inflammatory drugs, and anabolic hormones along with conventional nutritional supplementation may provide potential interventions to improve clinical outcome in ESRD patients.

Metabolism and clinical interest of serum transthyretin (prealbumin) in dialysis patients

Chronic renal failure is responsible for an increase in serum concentrations of transthyretin. Elevated serum transthyretin during renal insufficiency is secondary to the lack of retinol-binding protein degradation in renal tubules and to the subsequent increase in the fraction of transthyretin bound to retinol-binding protein. In both hemodialysis and peritoneal dialysis patients, serum transthyretin was demonstrated to be a reliable marker of nutritional status, exhibiting significant relationships with energy and protein intakes as well as with fat stores and lean body mass. Serum transthyretin levels less than 300 mg/l were shown to be associated with an increased risk of morbidity and mortality in dialysis patients. The predictive value of transthyretin was shown to be independent of serum albumin. Regular measurements of both serum albumin and transthyretin make it possible to detect patients whose prognosis is compromised by malnutrition and in whom an active nutritional therapy must be undertaken. Simultaneous measurements of inflammatory markers such as serum C-reactive protein are required to evaluate the role of inflammation in serum albumin and transthyretin variations. These low-cost protein parameters should be incorporated in the regular assessment of dialysis patients and measured every 1 to 3 months.

Intradialytic parenteral nutrition improves protein and energy homeostasis in chronic hemodialysis patients

Decreased dietary protein intake and hemodialysis-associated protein catabolism are among several factors that predispose chronic hemodialysis (CHD) patients to protein calorie malnutrition. Since attempts to increase protein intake by dietary counseling are usually ineffective, intradialytic parenteral nutrition (IDPN) has been proposed as a potential therapeutic approach in malnourished CHD patients. In this study, we examined protein and energy homeostasis during hemodialysis in seven CHD patients at two separate hemodialysis sessions, with and without IDPN administration. Patients were studied 2 hours before, during, and 2 hours following a hemodialysis session, using a primed constant infusion of L-(1-(13)C) leucine and L-(ring-(2)H(5)) phenylalanine. Our results showed that IPDN promoted a large increase in whole-body protein synthesis and a significant decrease in whole-body proteolysis, along with a significant increase in forearm muscle protein synthesis. The net result was a change from an essentially catabolic state to a highly positive protein balance, both in whole-body and forearm muscle compartments. We conclude that the provision of calories and amino acids during hemodialysis with IDPN acutely reverses the net negative whole-body and forearm muscle protein balances, demonstrating a need for long-term clinical trials evaluating IDPN in malnourished CHD patients.

Nutrition support of the chronically critically ill patient

Providing nutrition and metabolic support to the CCI patient is based on the rational application of scientifically derived data and clinical experience with this unique population. Much of the data presented has been extrapolated from the critically ill ICU patients and the chronically ill hospitalized or nursing home patient, as there are limited data solely based on an experience with the CCI [table: see text] patient population. The key principles are: (1) primacy of protein provision and avoidance of overfeeding energy, (2) use of combined modality (enteral, parenteral, and oral) nutrition to meet needs as required, (3) use of adjunctive agents to promote nitrogen retention when needed, and (4) recognition of and adjustment for altered nutrient requirements (Table 3).

Practical aspects of intradialytic nutritional support

A critical review of recent international literature related to the use of intradialytic parenteral nutrition is given. The role of intradialytic parenteral nutrition as a therapy in malnourished hemodialysis patients is established and the need for systematic monitoring of this population at high risk of malnutrition is emphasized.

Treatment of protein-energy malnutrition in chronic nonmalignant disorders

Protein-energy malnutrition (PEM) is common in connection with chronic disease and is associated with increased morbidity and mortality. Because the risk of PEM is related to the degree of illness, the causal connections between malnutrition and a poorer prognosis are complex. It cannot automatically be inferred that nutritional support will improve the clinical course of patients with wasting disorders. We reviewed studies of the treatment of PEM in cases of chronic obstructive pulmonary disease, chronic heart failure, stroke, dementia, rehabilitation after hip fracture, chronic renal failure, rheumatoid arthritis, and multiple disorders in the elderly. Several methodologic problems are associated with nutrition treatment studies in chronically ill patients. These problems include no generally accepted definition of PEM, uncertain patient compliance with supplementation, and a wide range of outcome variables. Avail-able treatment studies indicate that dietary supplements, either alone or in combination with hormonal treatment, may have positive effects when given to patients with manifest PEM or to patients at risk of developing PEM. In chronic obstructive pulmonary disease, nutritional treatment may improve respiratory function. Nutritional therapy of elderly women after hip fractures may speed up the rehabilitation process. When administered to elderly patients with multiple disorders, diet therapy may improve functional capacity. The data regarding nutritional treatment of the conditions mentioned above is still inconclusive. There is still a great need for randomized controlled long-term studies of the effects of defined nutritional intervention programs in chronically ill and frail elderly with a focus on determining clinically relevant outcomes.

Prealbumin is as important as albumin in the nutritional assessment of hemodialysis patients

BACKGROUND

Although serum prealbumin is considered a valid indicator of nutritional status in hemodialysis patients, there is relatively little evidence that its determination is of major prognostic significance. In this study, we aimed to determine the independent association of serum prealbumin with survival in hemodialysis patients, after adjusting for serum albumin and other indicators of protein energy nutritional status.

METHODS

Serum prealbumin was measured in more than 1600 maintenance hemodialysis patients. We determined the correlations among prealbumin and other indicators of nutritional status, including serum albumin, and bioimpedance-derived indicators of body composition. The relationship between serum prealbumin and survival was determined using proportional hazards regression.

RESULTS

The serum albumin was directly correlated with the serum prealbumin (r = 0.47, P < 0.0001), but still explained <25% of the variability in prealbumin. Prealbumin was inversely related to mortality, with a relative risk reduction of 6% per 1 mg/dL increase in prealbumin, even after adjusting for case mix, serum albumin, and other nutritional indicators. The increase in risk with lower serum prealbumin concentrations was observed whether the serum albumin was high or low.

CONCLUSION

In hemodialysis patients, the serum prealbumin provides prognostic value independent of the serum albumin and other established predictors of mortality in this population.