Effect of intradialytic parenteral nutrition on mortality rates in end-stage renal disease care

Oral supplementation of branched-chain amino acid improves nutritional status in elderly patients on chronic haemodialysis

BACKGROUND

Anorexia may be associated with decreased plasma levels of branched-chain amino acids (BCAA). In malnourished elderly haemodialysis (HD) patients, oral BCAA supplementation may improve anorexia, resulting in improved nutritional status.

METHODS

Among 44 elderly (age >70 years) patients on chronic HD, 28 patients with low plasma albumin concentration (<3.5 g/dl) were classified as the malnourished group; they also suffered from anorexia. The other 16 patients did not complain of anorexia and were classified as the well-nourished group. We performed a 12-month, placebo-controlled, double-blind study on the malnourished group. Fourteen patients each received daily oral BCAA supplementation (12 g/day) or a placebo in random order in a crossover trial for 6 months. Body fat percentage, lean body mass, plasma albumin concentration, dietary protein and caloric intakes, and plasma amino acid profiles were monitored.

RESULTS

Lower plasma levels of BCAA and lower protein and caloric intakes were found in the malnourished group as compared to the well-nourished group. In BCAA-treated malnourished patients, anorexia and poor oral protein and caloric intakes improved within a month concomitant with the improvement in plasma BCAA levels over the values in well-nourished patients. After 6 months of BCAA supplementation, anthropometric indices showed a statistically significant increase and mean plasma albumin concentration increased from 3.31 g/dl to 3.93 g/dl. After exchanging BCAA for a placebo, spontaneous oral food intake decreased, but the favourable nutritional status persisted for the next 6 months. In 14 patients initially treated with a placebo, no significant changes in nutritional parameters were observed during the first 6 months. However, positive results were obtained by BCAA supplementation during the subsequent 6 months, and mean plasma albumin concentration increased from 3.27 g/dl to 3.81 g/dl.

CONCLUSIONS

Normalization of low plasma levels of BCAA by oral supplementation can reduce anorexia and significantly improve overall nutritional status in elderly malnourished HD patients.

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.

National kidney foundation K/DOQI clinical practice guidelines for nutrition in chronic renal failure

The National Kidney Foundation Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Nutrition in Chronic Renal Failure was recently published in the American Journal of Kidney Diseases. This publication provides 27 clinical practice guidelines for adults and 10 clinical practice guidelines for children. The adult guidelines focus primarily on patients undergoing maintenance dialysis therapy, although there are several clinical practice guidelines on nutritional issues for patients with advanced chronic renal failure (CRF) not undergoing dialysis therapy. The pediatric guidelines focus entirely on children undergoing maintenance dialysis treatment. The present article discusses a number of the more prominent clinical practice guidelines for the adults. Among these is the recommendation that the protein-energy nutritional status in these patients should be assessed by a panel of measures rather than by any single measure. Also, non-dialyzed patients with advanced CRF (ie, glomerular filtration rate <25 mL/min) and those undergoing maintenance hemodialysis or chronic peritoneal dialysis should be prescribed a dietary energy intake of 35 kcal/kg/day for patients who are <60 years of age and 30 kcal/kg for patients >/=60 years of age. Maintenance hemodialysis patients should be prescribed 1.2 g protein/kg/d; chronic peritoneal dialysis patients should be prescribed 1.2 to 1.3 g protein/kg/d. For non-dialyzed patients with CRF (glomerular filtration rate <25 mL/min), 0.60 g protein/kg/d should be prescribed. For patients who will not accept such a diet or are unable to maintain an adequate energy intake on that diet, a protein intake of up to 0.75 g protein/kg/d may be prescribed. At least 50% of the protein intake for all of these patients should be of high biologic value. A guideline concerning indications for inaugurating maintenance dialysis treatment or renal transplantation on the basis of deteriorating nutritional status is also given.

Amino acid losses during hemodialysis with polyacrylonitrile membranes: effect of intradialytic amino acid supplementation on plasma amino acid concentrations and nutritional variables in nondiabetic patients

BACKGROUND

Malnutrition is highly prevalent in hemodialysis patients. Amino acid (AA) losses during the dialysis procedure may be a contributing factor.

OBJECTIVES

The objectives of this study were 1) to prospectively evaluate AA losses and their effect on plasma AA concentrations during dialysis with polyacrylonitrile at baseline and after administration of AAs by intradialysis and 2) to investigate the effects of intradialytic AA supplementation on nutritional status.

DESIGN

Seventeen stable patients without diabetes who were receiving hemodialysis were studied. In the first phase, AA losses were evaluated over 2 wk in 10 patients randomly assigned to receive AA supplementation. AA losses were analyzed during the first week without supplementation and during the second week with AA administration. In the second phase, the patients' nutritional status was investigated after 3 mo of AA supplementation and was compared with those in 7 patients not receiving AAs.

RESULTS

Mean +/- SD) AA losses during a 4-h dialysis session were 12 +/- 2 g; there was a significant decrease in plasma AA concentrations (386 +/- 298 micromol/L for essential and 902 +/- 735 micromol/L for nonessential AAs). After administration of AAs, the losses increased to 28 +/- 4 g. However, this procedure produced a positive net balance of AAs (10.6 +/- 5.6 g for total AAs), preventing a reduction in plasma concentrations. After 3 mo of AA administration, there was a significant increase in protein catabolic rate and serum albumin and transferrin. This improvement occurred without any change in the dialysis dose, ruling out the possibility that an increase in dialysis efficiency played a role.

CONCLUSIONS

Intradialysis adequately provides AA supplements, prevents reductions in plasma AA concentrations, and favorably affects the nutritional status of patients receiving hemodialysis.

Successful intradialytic parenteral nutrition after abdominal "Catastrophes" in chronically hemodialysed patients

OBJECTIVE

To assess the therapeutic contribution of intradialytic parenteral nutrition (IDPN) in four acutely ill, hypercatabolic, hemodialysed patients. All underwent major surgery, complicated by infection and malnutrition.

DESIGN

A retrospective clinical study.

SETTING

An in-center hemodialysis unit, at a tertiary referral hospital.

PATIENTS

Patient 1: a young woman, with a good renal transplant. Developed gastric lymphoma, which required gastrectomy. After cessation of immunosuppression, "lost" her kidney and returned to hemodialysis. Received IDPN for 4 months and recovered well from severe malnourishment. Patient 2: an elderly, malnourished man, on continuous ambulatory peritoneal dialysis (CAPD). Developed biliary peritonitis and bacteremia. In a 3-month period, the patient had four operations. Maintained on IDPN for 4 months. Patient 3: a young and obese man, who suffered from life-threatening staphylococcal aureus peritonitis, resulting in widespread bowel adhesions. Underwent repeated aspirations of purulent ascites, laparoscopy, and explorative laparotomy. IDPN was administered for 4 months and stopped on the patient's request. Patient 4: a young man, who after cadaveric renal transplantation remained hospitalized for 6 months because of acute rejection and peritoneal and retroperitoneal abscesses. Had major surgery performed seven times. Received IDPN for 6 months, and is now well.

RESULTS

All four patients benefited from 4 to 6 months of IDPN, as an integral part of intensive supportive and nutritional treatment. Weight loss was halted, as patient appetite returned and oral nutrition became adequate. Estimated daily protein intake reached 1.2 g/kg, while caloric intake rose to nearly 30 kcal/kg/d (Table 3). Mean serum albumin levels increased from 25.5 g/L +/- 0.9 g/L to 38.0 g/L +/- 1.5 g/L. No adverse side effects were seen from IDPN.

CONCLUSION

IDPN is a worthwhile part of treatments used in the catabolic, postoperative hemodialysed patient. It is safe and efficient when used over a 6-month period in trying to attenuate existing, or worsening malnutrition in these patients. It should be commenced at an early stage in these patients, after attempts at oral nutritional support have been deemed inadequate.

Management of protein and energy intake in dialysis patients

Malnutrition is not uncommon in patients with end-stage renal disease treated with maintenance dialysis. The presence of several abnormal parameters of nutritional status are reported to be predictive of poorer outcomes in these patients, compared to dialysis patients without evidence of malnutrition. This article describes methods that may be used to recognize the presence of malnutrition in end-stage renal disease patients and the management of protein and energy intake. Whether the correction of malnutrition will improve outcomes, such as morbidity and mortality, is unknown.

Effect of intradialytic parenteral nutrition on delivered Kt/V

The purpose of the study is to determine the effect of intradialytic parenteral nutrition (IDPN) and its components on delivered Kt/V (Kt/Vd). Nineteen patients undergoing routine outpatient hemodialysis and receiving IDPN were enrolled onto this prospective, crossover study. To reduce the confounding of time, assigned treatment in the first week was random, with patient crossover in the fourth week. Patients served as their own controls. In the successive 6 weeks, patients received IDPN solutions differing in whether amino acids (AAs), dextrose, or lipids were included or excluded. The primary end point was Kt/Vd, measured with a single-pool, variable-volume urea kinetic model. Other factors with the potential to impact on Kt/Vd were controlled and/or monitored. The administration of IDPN with all three components resulted in a significantly reduced mean Kt/Vd. When patients received AA-containing solutions, mean Kt/Vd was significantly less than when IDPN was withheld. Administration of solutions without AA resulted in a mean Kt/Vd not significantly different from mean Kt/Vd when IDPN was withheld. The mean prescribed Kt/V did not differ from mean Kt/Vd when IDPN was withheld. Simulation analyses of increased urea generation (Gu) showed an increase in patient urea volume and decreased Kt/V similar to the study findings. AA-containing IDPN solutions resulted in a significant reduction in Kt/Vd, possibly mediated by increased Gu. Administration of IDPN solutions may have important clinical and economic consequences that warrant further investigation.

Role of fermentable carbohydrate supplements with a low-protein diet in the course of chronic renal failure: experimental bases

During the past few years, considerable attention has been given to the impact of nutrition on kidney disease. The question arises of whether the effect of a moderate dietary protein restriction could be reinforced by enrichment of the diet with fermentable carbohydrates. Feeding fermentable carbohydrates may stimulate the extrarenal route of nitrogen (N) excretion through the fecal route. Such an effect has been reported in several species, including healthy humans and patients with chronic renal failure (CRF). Furthermore, studies of these subjects show that the greater fecal N excretion during the fermentable carbohydrate supplementation period was accompanied by a significant decrease in plasma urea concentration. In animal models of experimental renal failure, the consumption of diets containing fermentable carbohydrates results in a greater rate of urea N transfer from blood to the cecal lumen, where it is hydrolyzed by bacterial urease before subsequent microflora metabolism and proliferation. Therefore, this results in a greater fecal N excretion, coupled with a reduction in urinary N excretion and plasma urea concentration. Because elevated concentrations of serum urea N have been associated with adverse clinical symptoms of CRF, these results suggest a possible usefulness of combining fermentable carbohydrates with a low-protein diet to increase N excretion through the fecal route. Further investigations in this population of patients of whether fermentable carbohydrates in the diet may be beneficial in delaying or treating the symptoms and chronic complications of CRF will certainly emerge in the future. This should be realized without adversely affecting nutritional status and, as far as possible, by optimizing protein intake for the patients without being detrimental to renal function.

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

BACKGROUND

Malnutrition is a frequent problem of patients on intermittent hemodialysis and substantially contributes to their morbidity and mortality.

METHODS

In 26 hemodialysis patients who, despite dietary advice and oral nutritional supplements, still had malnutrition, the feasibility and effects of a specific intradialytic parenteral nutritional (IPN) regimen were evaluated during a 9-month study period. An IPN solution consisting of 250 mL glucose 50%, 250 mL lipids 20%, and 250 mL amino acids 7% was infused i.v. three times a week during the dialysis session. At the end of each dialysis session an additional volume of 250 mL amino acids was infused as a rinsing fluid. Insulin was administered i.v. before dialysis.

RESULTS

Of the 26 enrolled patients, 16 completed the study. The remaining 10 patients withdrew mainly because of muscle cramps and nausea during the initiation phase of the treatment, when sodium was not present in the IPN fluid but was supplemented intermittently. In the 16 treated patients, body weight, which had decreased in the pretreatment period from 58.2+/-1.3 kg (-6 months) to 54.8+/-10.1 kg at the start of the study, increased again up to 57.1+/-10.7 kg after 9 months IPN (p < .05). Serum transferrin and prealbumin rose from 1.7+/-0.4 to 2.0+/-0.4 g/L and from 0.23+/-0.05 to 0.27+/-0.10 g/L, respectively. Bone densitometry showed an increase of tissue mass, mostly related to a rise in fat tissue. Triceps skinfold (p < .05) and arm muscle compartment of the midarm (p = .07) increased as well. No such changes were observed in the patients who withdrew from treatment.

CONCLUSIONS

An i.v. hyperalimentation regimen applied to malnourished hemodialysis patients results in a rise of body weight and in a limited, but significant, change of some parameters of nutritional status. The rise in body weight is at least in part attributable to an increase of body fat, without changes in plasma lipid levels.

Recommended criteria for initiating and discontinuing intradialytic parenteral nutrition therapy

The indications for intradialytic parenteral nutrition (IDPN) in patients with end-stage renal disease remain controversial. Medicare has taken a position to severely limit the use of this form of nutritional therapy. Are there patients who do not meet the government criteria, yet would benefit from this therapy? Studies are required to answer this question, but they may be years away. In the interim, identification of appropriate patients, development of appropriate criteria for initiating and discontinuing therapy, as well as a proper reimbursement process should be considered for the treatment of severe malnutrition in this population of patients. This article discusses these topics and outlines a different approach to the use of IDPN.

Pathophysiology of protein-energy wasting in chronic renal failure

There is a high prevalence of protein-energy malnutrition in both nondialyzed patients with advanced chronic renal failure and in those individuals with end-stage renal disease who are receiving maintenance hemodialysis or chronic peritoneal dialysis therapy. Approximately one-third of maintenance dialysis patients have mild to moderate protein-energy malnutrition, and about 6 to 8 percent of these individuals have severe malnutrition. These statistics are of major concern because markers of protein-energy malnutrition are strong predictors of morbidity and mortality. The causes of protein-energy malnutrition in patients with chronic renal failure include: (1) decreased energy or protein intake; (2) concurrent chronic illnesses, and superimposed acute illnesses and possibly increased inflammatory cytokines; (3) the catabolic stimulus of hemodialysis; (4) losses of nutrients into dialysate, particularly amino acids, peptides, protein (with peritoneal dialysis), glucose (when hemodialysis is performed with glucose-free dialysate) and water-soluble vitamins; and (5) diagnostic or therapeutic (e.g., prednisone therapy) procedures that reduce nutrient intake or engender net protein breakdown. Other theoretically possible causes for protein-energy malnutrition include (6) chronic blood loss; (7) endocrine disorders (especially resistance to insulin and insulin-like growth factor-I, hyperglucagonemia, hyperparathyroidism and deficiency of 1,25-dihydroxycholecalciferol); (8) products of metabolism that accumulate in renal failure and may induce wasting, such as organic and inorganic acids; (9) loss of the metabolic actions of the kidney; and (10) the accumulation of toxic compounds that are taken up from the environment (e.g., aluminum).

Therapeutic approaches to malnutrition in chronic dialysis patients: the different modalities of nutritional support

Protein-energy malnutrition (PEM) is a common complication in maintenance hemodialysis and chronic peritoneal dialysis patients and is a powerful predictor of morbidity and mortality. Although this association does not prove that malnutrition is a cause of this increased morbidity and mortality, it is consistent with this possibility. There are a number of modalities of nutritional support for the prevention or treatment of PEM in maintenance dialysis patients. Routine methods include preventing PEM before the onset of maintenance dialysis therapy, dietary counseling, maintenance of an adequate dose of dialysis, avoidance of acidemia, and aggressive treatment of superimposed catabolic illness. Specific treatments of chronic dialysis patients who have persistently inadequate nutritional intake include food supplements, enteral tube feeding, intradialytic parenteral nutrition, and total parenteral nutrition. More experimental forms of nutritional therapy include dialytic nutrition (eg, using peritoneal dialysate or hemodialysate that contains amino acids), appetite stimulants (eg, megestrol acetate), or growth factors (eg, anabolic steroids, recombinant human growth hormone, or insulin-like growth factor-I).

Proposed clinical trials in the evaluation of intradialytic parenteral nutrition

New revised policies relating to intradialytic parenteral nutrition (IDPN) reimbursement by Medicare have made it difficult, if not impossible, to qualify malnourished hemodialysis patients for this potentially useful therapy. These policies were adopted by Medicare because of a lack of studies that provide clear documentation of the medical benefits of IDPN or their cost-effectiveness. We propose a limited study of the role of IDPN with and without anabolic growth factors to improve predefined nutritional parameters and document its cost-effectiveness by monitoring hospitalization and mortality. The proposed study will be multicenter, prospective, limited to severely malnourished patients, and will include a control group that would receive standard of care.

An evidence-based evaluation of intradialytic parenteral nutrition

Malnutrition is a well-recognized comorbid condition in dialysis patients that contributes to the increased mortality seen in these patients. Multiple interventions have been tried in an effort to decrease mortality. The most controversial of these is intradialytic parenteral nutrition. In an era of high costs and shrinking budgets, it is important to critically examine published data to determine the quality of the data and to determine whether the reported results are valid and clinically applicable. Using an evidence-based approach, all published literature concerning intradialytic parenteral nutrition was reviewed, quality of the data determined, number needed to treat (NNT) calculated, and potential costs of treatment determined. Twenty-four studies that met the search criteria were identified. Only three studies were randomized; one of these was a feasibility study, and the other two were only of level B quality. The remaining studies were either case reports or observational studies of level C quality. The absolute risk reduction in mortality with intradialytic parenteral nutrition (IDPN) usage ranged from 0.12 to 0.65; relative risk reduction ranged from 0.48 to 0.74; NNT ranged from 2 to 17; cost ranged from $150,000,000 to $877,500,000; and 588 to 9,750 patients might be expected to experience a decrease in mortality. The results of this review indicate that the data supporting the use of IDPN are weak and a clear recommendation cannot be made. IDPN use in hemodialysis patients seems to be associated with decreased mortality. IDPN should be available for use in patients who meet previously published guidelines and who are not normoalbuminemic.

Dialytic nutrition: provision of amino acids in dialysate during hemodialysis

Maintenance hemodialysis (MHD) patients are frequently malnourished, a condition associated with high morbidity and mortality. Amino acid (AA) losses in dialysate may enhance protein malnutrition in patients with low food intake. We studied the possibility of providing AA in dialysate during MHD to either prevent AA losses or as a nutritional supplement. Six clinically stable men were studied during three hemodialysis treatments. The first treatment was performed using the usual dialysate (0XAA). The two other treatments were performed using a dialysate containing an amount of AA equal to normal plasma AA concentrations (1XAA) or to three times the normal plasma AA concentrations (3XAA). During the OXAA treatment, the total AA losses were 10.0 +/- 0.9 (SEM) grams (g) and the total AA concentrations in plasma decreased by 49 +/- 4%. During the 1XAA treatment, the total AA balance was +0.8 +/- 1.8 g and there was no significant change in the postdialysis plasma total AA. With the 3XAA treatment, the patients gained 36.9 +/- 4.1 g of AA during the hemodialysis treatment and the plasma total AA levels increased by 45 +/- 9%. No side effects were observed. These findings indicate that it may be feasible to provide AA supplements to MHD patients by adding AA to hemodialysate.

Determinants of albumin concentration in hemodialysis patients

Hypoalbuminemia predicts mortality in hemodialysis patients with end-stage renal disease and is assumed to result from malnutrition. To investigate a possible alternative cause, we evaluated the relationships between serum albumin (Salb) and serum levels of two positive acute-phase proteins: C-reactive protein (CRP) and serum amyloid A (SAA). We also examined the relationship between Salb and dialysis dose delivered (Kt/V) and normalized protein catabolic rate (PCRn) measured during 3 consecutive months in a group of 115 patients. Serum albumin was measured monthly for 5 months. SAA levels were not increased in the majority of patients, despite its low molecular weight (8 kd), and predialysis concentrations were independent of residual renal function, compatible with a nonrenal site of metabolism. Both CRP and SAA levels correlated negatively with Salb both by linear regression and by multiple regression analysis (P < 0.001). CRP correlated with fibrinogen (P < 0.005). Salb also correlated positively with PCRn (P = 0.001), but not with Kt/V. The Kt/V did not correlate with PCRn. While CRP and SAA correlated with one another, neither variable correlated with PCRn. When either SAA or CRP was high, Salb was low regardless of PCRn. Thus, there are two separate independent factors predicting Salb--markers of inflammation and protein intake--but high concentrations of acute-phase proteins have a greater impact on Salb than does low PCRn. Activity of the acute-phase response is an important predictor of low Salb in hemodialysis patients independently of nutritional factors.

Use of the medical differential diagnosis to achieve optimal end-stage renal disease outcomes

Compared with the general population, end-stage renal disease (ESRD) patients continue to have a higher than expected morbidity and mortality. Hypoalbuminemia, anemia, hypertension, and inadequate dialysis are all thought to contribute to the high morbidity and mortality among ESRD patients. Anemia algorithms should help to standardize the approach to anemia and the use of recombinant human erythropoietin (rHuEPO), but clinicians still must review each patient individually, searching for and treating the multitude of interrelated factors that affect rHuEPO responsiveness. Hypoalbuminemia is a very strong predictor of increased morbidity and mortality in dialysis and nondialysis patients. The causes of hypoalbuminemia are multifactorial, and diagnosis of the cause of hypoalbuminemia is usually elusive. The basis of the poorer survival in US dialysis patients remains controversial, but inadequate dialysis has been implicated. To assure adequate dialysis, the dialysis prescription must be individualized for each patient, and delivered dialysis must be routinely monitored. Hypertension is associated with left ventricular hypertrophy, which is also an important determinant of survival in ESRD patients. Hypertension should be treated in ESRD patients in conjunction with other interventions that are known to reverse left ventricular hypertrophy. Special efforts must be made in the medical management of hypoalbuminemia, anemia, hypertension, and dialysis treatment adequacy to improve survival in patients with ESRD.

Modeling mortality risk in hemodialysis patients using laboratory values as time-dependent covariates

Proportional hazards analyses assume that the magnitude of mortality risk for a predictor variable remains proportional over time. In a time-dependent model, the explanatory variable violates this assumption, and repeat observations are required to accommodate the change in risk that occurs over time. Using a retrospective cohort design, we tested the following laboratory values for a time-by-covariate interaction: hematocrit (HCT), serum albumin (ALB), and serum creatinine (CR). A random sample of 4,083 hemodialysis patients whose specimens were analyzed in a central laboratory over a 3-year period served as the study group. Using the baseline observation, we discovered significant probability values for the interaction terms TIME*CR (P = 0.013) and TIME*ALB (P < 0.01). The beta coefficient for TIME*HCT was not significant, indicating that the proportional hazard assumption was not violated by this covariate. Based on these results, we fitted a multivariate regression model containing two time-dependent covariates (CR and ALB) using a data structure that incorporated repeat observations of these laboratory values. Patients with high ALB levels experienced the lowest mortality risk. Similarly, serum CR levels were higher in long-term survivors. This analysis verifies the clinical importance of monitoring ALB and CR levels over time and the hazard of using a single laboratory observation to make long-term projections. Additionally, the predictive values of the time-dependent covariates ALB and CR affirm the significance of nutritional approaches directed toward maintaining visceral and somatic protein content throughout renal replacement therapy.

Intradialytic parenteral nutrition: a useful therapy?

Malnutrition in hemodialysis patients is common and may affect as much as 40% of this population of patients. There are many causes of malnutrition and all must be considered before utilizing nutrition support to reverse the malnutrition. Intradialytic parenteral nutrition (IDPN) is a therapy that has become popular among US nephrologists despite the fact that there are no clear data that support its use or efficacy. A thorough review of published articles suggests a relationship between the use of IDPN and improved patient outcome measured by hospitalization rate and a decrease in mortality in certain subgroups. However, these studies have many confounding factors that prevent a definitive conclusion concerning the true efficacy of IDPN. This is very problematic since reimbursement changes for parenteral and enteral nutrition have been proposed by HCFA. The best recommendation that can be made for IDPN is that it may represent a useful form of nutrition support in the malnourished hemodialysis patient who has no other active disease processes, cannot ingest adequate nutrition by mouth, and has a contraindication to or a serious complication from enteral feeding. It is clearly not a therapy to be considered as the first line of nutrition support in these patients.

Intradialytic parenteral nutrition after small bowel resection

Malnutrition is frequently observed in the hemodialysis patient population. It may be associated with increased morbidity and mortality as well as affect overall quality of life, which may already be compromised from dialytic physical and psychological demands. In the past, intradialytic parenteral nutrition (IDPN) has been available to hemodialysis patients as an adjunct to their dietary intake. In this time of cost containment and the increasing need to scientifically justify the benefit of such therapies to have them paid for by third party reimbursers, IDPN is coming under much scrutiny. This report describes a case of inadequate enteral nutrient absorption in a malnourished hemodialysis patient. This is a case in which IDPN was beneficial and without which other alternatives would have proven more costly physically, emotionally, and economically to the patient.

Mechanisms of hypoalbuminemia in hemodialysis patients

Hypoalbuminemia is the most powerful predictor of mortality in end-stage renal disease. Since protein-calorie malnutrition can decrease albumin synthesis it is assumed that hypoalbuminemia results principally from malnutrition in these patients, but albumin synthesis may also be decreased as part of the acute-phase response, and hypoalbuminemia can also result from redistribution of albumin pools or from albumin losses. We measured albumin synthesis, fractional catabolic rate, and distribution from the turnover of [125I] human albumin in six hemodialysis patients with plasma albumin less than 35 mg/ml and in six patients with plasma albumin greater than 40 mg/ml. Patients with liver disease, HIV, or other infection were excluded. Both groups were maintained with high-flux polysulfone dialyzers for more than three months. Kt/Vurea and PCR were measured during each dialysis (N = 12 to 18/patient). A four-day calorie and protein intake was determined by dietary history and long-term nutritional status was determined anthropometrically. Measured variables included serum urea, creatinine, transferrin, and the positive acute-phase proteins alpha 2- macroglobulin, C-reactive protein, ferritin, and IGF-1. Albumin synthesis was significantly reduced in the low albumin group. There were no differences in dietary intake, body composition, PCR, BUN, creatinine, or Kt/Vurea. Plasma albumin concentration correlated negatively with ferritin, C-reactive protein and alpha 2-macroglobulin. Albumin synthesis rate correlated negatively with both alpha 2-macroglobulin and Kt/Vurea. Both plasma albumin concentration and synthesis rate correlated positively with IGF-1, and both were independent of PCR and all other nutrition-related variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Interventions to treat malnutrition in dialysis patients: the role of the dose of dialysis, intradialytic parenteral nutrition, and growth hormone

Protein and calorie malnutrition often starts before initiation of dialysis, and reflects the anorexia and the catabolic state of chronic renal failure. In the face of inadequate dialysis, which perpetuates the uremic state, malnutrition often worsens. Several studies, though not all, suggest that optimal dialysis improves nutritional status of dialysis patients. Such optimal dialysis now must include the use of biocompatible membranes to deliver Kt/V > 1.4 (urea reduction ratio > 65%). Additional interventions can include the use of enteral or intravenous hyperalimentation, and recombinant growth factors such as growth hormone or insulin-like growth factor-1. Importantly, studies to document the improvement in the morbidity and mortality of patients with these interventions are still needed and require large multicenter trials.

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

Hemodialysis patients who had received intradialytic parenteral nutrition (IDPN) during 1991 were identified. These patients were compared with unexposed controls after adjusting for demographic variables, baseline renal diagnosis, diabetic status, serum albumin (ALB), creatinine (CRE), and urea reduction ratio. At lower levels of ALB (< or = 3.4 g/dL), treatment with IDPN was associated with a reduction in the odds of death at 1 year, an effect that became stronger at lower levels of CRE (< or = 8.0 mg/dL). In contrast, treatment with IDPN in patients with normal ALB was associated with increased mortality. Time trend analyses of ALB and CRE demonstrated progressive increases toward pretreatment levels in IDPN recipients that were not evident in control subjects. These time trend data suggest that in undernourished hemodialysis patients, IDPN can effect the serum levels of valid biochemical surrogates of visceral and somatic protein nutrition. Albeit retrospective, the improvement in survival at year's end among patients with ALB < or = 3.4 g/dL suggests that malnutrition and its attendant ill effects in hemodialysis patients may respond to aggressive therapeutic intervention, such as IDPN. These important findings should be prospectively confirmed in a randomized clinical trial.