Does prolonged protein restriction preceding dialysis lead to protein malnutrition at the onset of dialysis?

The Role of Protein Restriction in the Progression of Chronic Kidney Disease

Even though nephrology has made much progress, reducing the progression of the chronic kidney disease remains, in fact, one of the biggest challenges. Long before the renal replacement therapy (RRT), it was known that limiting the protein could help almost all uremia symptoms. Although it was proposed as early as the 1960s, it only became widely used in the 1980s. By lowering the urea and other nitrogen wastes and lowering the metabolic acidosis, oxidative stress, and insulin resistance, limiting the amount of protein in your diet can help improve uremic symptoms. Also, limiting the protein in the diet positively controls the cardiovascular complications, including the arterial blood pressure and proteinuria reduction, which are risk factors for CKD progression. This mini-review examines the impact of protein restriction on the possibility of slowing CKD progression in depth.

Very low protein diet plus ketoacid analogs of essential amino acids supplement to retard chronic kidney disease progression

Background

A very low protein diet (VLPD) with ketoacid analogs of essential amino acids (KA/EAA) administration can remarkably influence protein synthesis and metabolic disturbances of patients with advanced chronic kidney disease (CKD), and may also slow the decline in renal function.

Methods

A retrospective cohort study was carried out to monitor renal progression and metabolic and nutritional status among 140 patients with CKD stage III or IV. One group (n = 70) was on a low protein diet (LPD) with 0.6 g of protein intake, and another group (n = 70) was on a VLPD with 0.3 g of protein and KA/EAA supplementation of 100 mg/kg/day for 12 months.

Results

At 12-month follow-up, estimated glomerular filtration rate (GFR) significantly decreased from 41.6 ± 10.2 to 36.4 ± 8.8 mL/min/1.73 m² (P < 0.001) and urine protein increased from 0.6 ± 0.5 to 0.9 ± 1.1 g/day (P = 0.017) in the LPD group, but no significant changes in estimated GFR and urine protein were found in the VLPD plus KA/EAA group. A significant mean difference in rate of change in estimated GFR (-5.2 ± 3.6 mL/min/1.73 m² per year; P < 0.001) was observed between the two groups. After Cox regression analysis, treatment with VLPD plus KA/EAA significantly protected against the incidence of declining GFR > 10% annually (adjusted hazard ratio, 0.42; 95% confidence interval, 0.23-0.79; P = 0.006) and significant correlations were found between using VLPD plus KA/EEA and increased GFR.

Conclusion

VLPD supplementation with KA/EAA is associated with delayed renal progression while preserving the nutritional status in the patients with CKD. Co-administration of VLPD and KA/EAA may prove an effective alternative to conservative management of CKD.

Individualized Hemodialysis Treatment: A Perspective on Residual Kidney Function and Precision Medicine in Nephrology

Background: Residual kidney function (RKF) is often expected to inevitably and rapidly decline among hemodialysis patients and, hence, has been inadvertently ignored in clinical practice. The importance of RKF has been revisited in some recent studies. Given that patients with end-stage renal disease now tend to initiate maintenance hemodialysis therapy with higher RKF levels, there seem to be important opportunities for incremental hemo­dialysis by individualizing the dose and frequency according to their RKF levels. This approach is realigned with precision medicine and patient-centeredness. Summary: In this article, we first review the available methods to estimate RKF among hemodialysis patients. We then discuss the importance of maintaining and monitoring RKF levels based on a variety of clinical aspects, including volume overload, blood pressure control, mineral and bone metabolism, nutrition, and patient survival. We also review several potential measures to protect RKF: the use of high-flux and biocompatible membranes, the use of ultrapure dialysate, the incorporation of hemodiafiltration, incremental hemodialysis, and a low-protein diet, as well as general care such as avoiding nephrotoxic events, maintaining appropriate blood pressure, and better control of mineral and bone disorder parameters. Key Message: Individualized hemodialysis regimens may maintain RKF, lead to a better quality of life without compromising long-term survival, and ensure precision medicine and patient-centeredness in nephrology practice.

Very low-protein diet to postpone renal failure: Pathophysiology and clinical applications in chronic kidney disease

The uremic syndrome is a metabolic disorder characterized by the impairment of renal handling of several solutes, the resulting accumulation of toxic products and the activation of some adaptive but detrimental mechanisms which all together contribute to the progression of renal damage. In moderate to advanced renal failure, the dietary manipulation of nutrients improves metabolic abnormalities and may contribute to delay the time of dialysis initiation. This commentary focuses on the physiopathological rationale and the clinical application of the very low-protein diet supplemented with ketoanalogs for the management of chronic kidney disease.

Very low protein diets supplemented with keto-analogues in ESRD predialysis patients and its effect on vascular stiffness and AVF Maturation

Background

Native arteriovenous fistula (AVF) is the most appropriate type of vascular access for chronic dialysis. Its patency rates depend on vascular wall characteristics. Ketoacid analogues of essential amino acids (KA/EAA) are prescribed in end-stage renal disease (ESRD) pre-dialysis patients to lower toxic metabolic products generation and improve nutritional status. We hypothesized that very-low protein diet (VLPD) supplemented with KA/EAA may influence arterial wall stiffness and affect AVF maturation rates and duration in pre-dialysis ESRD patients.

Methods

In a prospective, cohort, 3 years study we enrolled 67 consecutive non-diabetic early referral ESRD patients that underwent AVF creation in our hospital. Patients were divided in two groups based on their regimen 12 months prior to surgery: a VLPD supplemented with KA/EAA study group versus a low protein diet non-KA/EAA-supplemented control group. For each patient we performed serum analysis for the parameters of bone mineral disease, inflammation and nutritional status, one pulse wave velocity (PWV) measurement and one Doppler ultrasound (US) determination prior the surgery, followed by consequent Doppler US assessments at 4, 6, 8 and 12 weeks after it. Rates and duration of mature AVF achievement were noted. We used logistic regression to analyze the association between AVF maturation and KA/EAA administration, by comparing rates and durations between groups, unadjusted and adjusted for systolic blood pressure, C-reactive protein, PWV, phosphorus values. All parameters in the logistic model were transformed in binary variables. A p-value < α = 0.05 was considered significant; data were processed using SPSS 16 software and Excel.

Results

In the study group (n = 28, aged 57 ± 12.35, 13 females) we registered better serum phosphate (p = 0.022) and C-reactive protein control (p = 0.021), lower PWV (p = 0.007) and a higher percent of AVF creation success (33.3 % versus 17.8 %, p < 0.05). AVF maturation duration was lower in study group (5.91 versus 7.15 weeks, p < 0.001).

Conclusions

VLPD supplemented with KA/EAA appear to improve the native AVF primary outcome, decreasing the initial vascular stiffness, possible by preserving vascular wall quality in CKD patients through a better serum phosphate levels control and the limitation of inflammatory response.

Do ketoanalogues still have a role in delaying dialysis initiation in CKD predialysis patients?

Early versus later start of dialysis is still a matter of debate. Low-protein diets have been used for many decades to delay dialysis initiation. Protein-restricted diets (0.3-0.6 g protein/kg/day) supplemented with essential amino acids and ketoanalogues (sVLPD) can be offered, in association with pharmacological treatment, to motivated stage 4-5 chronic kidney disease (CKD) patients not having severe comorbid conditions; they probably represent 30-40% of the concerned population. A satisfactory adherence to such dietary prescription is observed in approximately 50% of the patients. While the results of the studies on the effects of this diet on the rate of progression of renal failure remain inconclusive, they are highly significant when initiation of dialysis is the primary outcome. The correction of uremic symptoms allows for initiation of dialysis treatment at a level of residual renal function lower than that usually recommended. Most of the CKD-associated complications of cardiovascular and metabolic origin, which hamper both lifespan and quality of life, are positively influenced by the diet. Lastly, with regular monitoring jointly assumed by physicians and dietitians, nutritional status is well preserved as confirmed by a very low mortality rate and by the absence of detrimental effect on the long-term outcome of patients once renal replacement therapy is initiated. On account of its feasibility, efficacy and safety, sVLPD deserves a place in the management of selected patients to safely delay the time needed for dialysis.

Influence of ketoanalogs supplementation on the progression in chronic kidney disease patients who had training on low-protein diet

AIM

A low-protein diet (LPD) is a conservative treatment in patients with chronic kidney disease (CKD) to improve uremic symptoms and slow the progression of renal dysfunction. However, the deleterious effects of protein restriction on nutritional status have raised concern. We investigated whether ketoanalogs supplementation in CKD patients who had training on LPD retards the progression of CKD and maintains nutritional status.

METHODS

Data were collected retrospectively from 120 consecutive patients in the CKD stages III and IV. Firstly all patients were restricted to LPD alone for 6 months (LPD alone), and then ketoanalogs of essential amino acids (KA) were supplemented for 6 months.

RESULTS

The adequate LPD had not achieved in both periods. The declining slopes of glomerular filtration rate (GFR) during the LPD + KA period were significantly lower than those during the LPD alone period. This improvement in GFR was apparent in both subjects with diabetics and non-diabetic patients. Mean serum total cholesterol levels decreased in LPD + KA compared with LPD alone period. However, serum albumin levels did not change. Responders showed a higher prevalence of diabetes and higher serum albumin levels during the LPD alone period. Multivariate analysis revealed that responsiveness to LPD + KA was independently related to diabetes (p = 0.006) and high serum albumin levels (p = 0.011) in the LPD alone period.

CONCLUSION

KA supplementation on over LPD delayed the progression of CKD without deteriorating nutritional status, and initial serum albumin levels could be an independent factor.

Long-term outcome on renal replacement therapy in patients who previously received a keto acid-supplemented very-low-protein diet

BACKGROUND

The consequences of a supplemented very-low-protein diet remain a matter of debate with regard to patient outcome before or after the onset of renal replacement therapy.

OBJECTIVE

We evaluated the long-term clinical outcome during maintenance dialysis and/or transplantation in patients who previously received a supplemented very-low-protein diet.

DESIGN

We assessed the outcome of 203 patients who received a supplemented very-low-protein diet for >3 mo (inclusion period: 1985-2000) and started dialysis after a mean diet duration of 33.1 mo (4-230 mo).

RESULTS

The survival rate in the whole cohort was 79% and 63% at 5 and 10 y, respectively. One hundred two patients continued with chronic dialysis during the entire follow-up, and 101 patients were grafted at least once. Patient outcomes were similar to those of the French Dialysis Registry patients for the dialysis group and similar to the 865 patients who were transplanted in Bordeaux during the same period for the transplant group. There was no correlation between death rate and duration of diet.

CONCLUSIONS

The lack of correlation between death rate and duration of diet and the moderate mortality rate observed during the first 10 y of renal replacement therapy confirm that a supplemented very-low-protein diet has no detrimental effect on the outcome of patients with chronic kidney disease who receive renal replacement therapy.

The effect of low-protein diet supplemented with ketoacids in patients with chronic renal failure

Ismert, hogy az étrendi fehérjemegszorítás lassítja a krónikus vesebetegség progresszióját. Ha a fehérjebevitel kevesebb mint 0,5-0,6 g/ttkg/nap, a diétát esszenciális aminosavakkal/ketosavakkal szükséges kiegészíteni. A szerzők tanulmányukban a hosszú időn keresztül ketosavakkal kiegészített fehérjeszegény diéta hatását vizsgálták krónikus veseelégtelenségben szenvedő betegekben a veseelégtelenség progressziójára, a kalcium- és foszforanyagcserére, a betegek tápláltsági állapotára, továbbá felmérték a betegek complience-ét. Ötvenegy beteget kezeltek 12–57 hónapig (átlagos kezelési idő: 26 hónap). A szérumkreatinin-érték átlaga 349,72±78,04 µmol/l-ről 460,66±206,66 µmol/l-re emelkedett, amely 27 µmol/l/év, illetve 2,3 µmol/l/hó szérumkreatinin-növekedést jelentett. A Cockroft–Gault-formula alapján számolt glomerulusfiltrációs ráta (GFR) 21,52±7,84 ml/min-ról 18,22±7,76 ml/min-ra csökkent, ami 0,83 ml/min/év, illetve 0,07 ml/min/hó GFR-csökkenést jelentett. Lineáris regressziós analízissel az 1/szérumkreatinin versus időegyenes dőlésszöge 0,0018 volt. A szérumparathormon-szint szignifikánsan csökkent, a szérumkalcium, -foszfor szintje nem változott. A betegek tápláltsági állapota (a BMI, szérumalbumin, szubjektív tápláltsági felmérés alapján) a folyamatos és intenzív diétás edukációnak köszönhetően nem romlott, a betegek tartani tudták az alacsony fehérjetartalmú diétát a kezelés hosszú időtartama alatt. Eredményeik igazolják, hogy a ketosavakkal kiegészített fehérjeszegény diéta hatásos a veseelégtelenség progressziójának csökkentésében, előnyösen befolyásolja a kalcium- és foszforanyagcserét, nem rontja a betegek tápláltsági állapotát.

Positive effects of protein restriction in patients with chronic kidney disease

OBJECTIVES

The potential benefit or harm of low-protein diets (LPDs) for patients with chronic kidney disease has been debated. This study sought to investigate the effects of treatment with LPDs on nutritional markers, morbidity, and survival during subsequent dialysis. A second objective was to evaluate the effect of LPDs on renal function and the start of dialysis.

DESIGN

This was a retrospective study of medical records.

SETTING

The setting was an outpatient nephrology and dialysis clinic.

PATIENTS

One-hundred twenty-two renal patients were recruited from the central dialysis registry of one clinic. The patients had been followed by a nephrologist for > or =6 months before dialysis. Sixty-one patients were treated with LPDs, and an equal number of control patients not treated with LPDs were matched for sex, age, dialysis modality, diabetes, and start of dialysis.

MAIN OUTCOME MEASURES

Main outcome measures included weight and weight change, serum albumin, glomerular filtration rate, morbidity, and mortality.

RESULTS

There was less mean weight loss in the LPD group the year before dialysis (0.14 kg/month, compared with the control group at 0.36 kg/month, P < .05). The level of serum albumin was higher in the LPD group at the start of dialysis (P < .01). The mean rate of progression during the 6 months before dialysis was lower in the LPD group (4.1 mL/min/year) than in the control group (13.4 mL/min/year) (P < .001). The LPD group had fewer days of hospitalization at the start of dialysis than the control group (8.2 vs 15.4 days, respectively, P < .01). There was no difference in mortality between groups 1, 2, or 5 years after starting dialysis.

CONCLUSIONS

Low-protein diets can reduce patient morbidity, preserve renal function, relieve uremic symptoms and improve nutritional status. The results suggest that LPDs can postpone the start of dialysis for 6 months, and entail substantial cost-savings. Low-protein diets should be used more generally in the renal community.

Nutritional status in patients with diabetes and chronic kidney disease: a prospective study

BACKGROUND

A poor nutritional status reduces the life expectancy of diabetes patients undergoing hemodialysis.

OBJECTIVE

The study objective was to specify the nutritional outcome in patients with chronic kidney disease (CKD) and well-controlled diabetes.

DESIGN

Forty-five diabetes patients with CKD were enrolled in a cooperative-care program designed to control glucose, blood pressure, LDL cholesterol, and the albumin excretion rate (AER). Their glomerular filtration rate (GFR), body composition, serum albumin (SA), and resting energy expenditure were assessed and compared at baseline and 2 y later.

RESULTS

Thirty-five patients did not start dialysis. Their glycated hemoglobin, blood pressure, LDL cholesterol, and AER improved; their GFR declined slowly (-3.3 mL x min(-1) x 1.73 m(-2) x y(-1)). Their body mass index (BMI), lean body mass, and SA increased. The GFR decline was correlated negatively with the initial BMI (r = -0.37, P < 0.05) and positively with the initial GFR (r = 0.34, P < 0.05). Ten patients started hemodialysis: except for higher total body water (P < 0.05) and extracellular volume (P < 0.01), their initial nutritional status did not differ significantly from that of 10 patients with comparable baseline severe CKD but without dialysis. At the second evaluation, patients on hemodialysis lost lean body mass, and their SA was lower than that of the patients with severe CKD (P = 0.05); lean body mass was unchanged and SA was higher (P = 0.01) in the patients with severe CKD. No significant difference was detected for resting energy expenditure.

CONCLUSIONS

Nutritional status improved in CKD patients with well-controlled diabetes without dialysis, and it deteriorated in patients who started dialysis. A high initial BMI was associated with a slower decline in GFR.

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.

Beneficial responses to modified diets in treating patients with chronic kidney disease

BACKGROUND

In rats, protein-restricted diets prolong survival from experimental chronic kidney disease (CKD). Diets for CKD patients that are restricted in protein and modified to limit the intake of phosphates and sodium not only reduce the accumulation of unexcreted metabolic products but also protect against hypertension and proteinuria. Their ability to slow progression of CKD is controversial, and this fact, plus concern about the nutritional adequacy of restricted diets, has limited this treatment strategy for CKD patients.

METHODS

Expected responses of CKD patients to dietary manipulation are examined. The influence of this strategy on complications of CKD, including results from the MDRD Study, is analyzed.

RESULTS

Dietary compliance with low-protein diets can be monitored from 24-hour urea excretion. Long-term therapy with diets containing 0.6 g protein/kg/day or less protein supplemented with essential amino acids or their ketoanalogues maintain body weight and normal values of serum proteins while reducing the accumulation of acid, phosphates, urea. Low-protein diets suppress proteinuria even when angiotensin-converting enzyme inhibitors are used. Patients in the MDRD Study who complied with the diet had a significant slowing of the rate of loss of glomerular filtration rate (GFR).

CONCLUSION

Successful dietary manipulation can ameliorate many complications of CKD. Low-protein diets are nutritionally safe, they reduce the accumulation of metabolic products, and they can suppress progressive loss of kidney function. Dietary manipulation should be an integral part of the therapy for patients with progressive CKD.

Body composition of patients on a very low-protein diet: a two-year survey with DEXA

BACKGROUND

It has been reported that patients on a very-low-protein diet (VLPD) maintain a satisfactory nutritional status because of a conserved adaptive metabolic response. However, only few studies have examined the course of nutritional status and body composition in the long term (2 years).

METHODS

Thirteen stable patients (8 men; age, 55 +/- 12 years; glomerular filtration rate (GFR), 15 +/- 5 mL/min) receiving a VLPD (0.3 g/kg/day protein) supplemented with amino acids and ketoanalogues (SVLPD) were studied for 2 years. A joint visit with a physician and a dietitian and routine blood and urine analyses were performed every month. Dual-energy x-ray absorptiometry (DEXA), which was used to assess modification of body composition, and GFR (urinary 51Cr-EDTA) and urinary urea and creatinine excretion, which were used to assess nutritional status and compliance to the diet, were assessed every 3 months.

RESULTS

GFR, albumin, and prealbumin levels remained stable. Urea urinary excretion decreased at 3 months and then slightly increased at 2 years, but the calculated protein intake remained low at 0.38 +/- 0.1 g/kg/day. Energy intake remained close to 30 kcal/kg/day. No significant change was observed for total fat mass or percent fat mass. After an initial decrease, lean body mass stabilized at 6 months and then increased significantly from 6 to 24 months (P =.02, paired t-test); the mean increase during this period was of 2 kg, that is, 4.6%. Urinary creatinine excretion showed the same profile. Total bone mass, lumbar or hip site bone mass, and Z-score significantly decreased from T0 to 1 and 2 years (P <.05).

CONCLUSION

This study confirms that a supplemented VLPD is nutritionally safe for a long period, but attention must be paid to bone mass.

Short-term effects of a very-low-protein diet supplemented with ketoacids in nondialyzed chronic kidney disease patients

OBJECTIVE

To evaluate the effects on the nutritional and metabolic parameters of a very-low-protein diet supplemented with ketoacids (VLPD+KA) in comparison with a conventional low-protein diet (LPD) in chronic kidney disease (CKD) patients.

DESIGN

Prospective, randomized, controlled clinical study.

SETTING

Outpatient Clinic of the Nephrology Division of Federal University of Sao Paulo, Brazil.

SUBJECTS

The study involved 24 patients with advanced CKD (creatinine clearance <25 ml/min) that were randomly assigned to either a VLPD+KA (VLPD+KA group, 12 patients) or to a conventional LPD with 0.6 g/kg/day (LPD group, 12 patients). The patients were followed for 4 months.

RESULTS

Nutritional status was adequately maintained with both diets for the studied period. Protein intake and serum urea nitrogen decreased significantly only in the VLPD+KA group (from 0.68+/-0.17 to 0.43+/-0.12 g/kg/day, P<0.05; from 61.4+/-12.8 to 43.6+/-14.9 mg/dl, P<0.001; respectively). Ionized calcium did not change in the VLPD+KA group but tended to decrease in the LPD group. Serum phosphorus tended to decrease in the VLPD+KA group probably as a result of a significant reduction in dietary phosphorus (529+/-109 to 373+/-125 mg/day, P<0.05) associated to the phosphorus-binding effect of the ketoacids. No change in these parameters was found in the LPD group. Serum parathormone increased significantly only in the LPD group (from 241+/-138 to 494+/-390 pg/ml, P<0.01). The change in PTH concentration was negatively correlated with changes in ionized calcium concentration (r=-0.75, P=0.02) and positively correlated with changes in serum phosphorus (r=0.71, P=0.03) only in the LPD group.

CONCLUSION

This study indicates that a VLPD+KA can maintain the nutritional status of the patients similarly to a conventional LPD. Besides, an improvement in calcium and phosphorus metabolism and a reduction in serum urea nitrogen were attained only with the VLPD+KA. Thus, VLPD+KA can constitute another efficient therapeutic alternative in the treatment of CKD patients.

Supplemented very low protein diet ameliorates responsiveness to erythropoietin in chronic renal failure

BACKGROUND

The aim of this study was to evaluate the relationship between uremic state and erythropoiesis in patients with predialytic chronic renal failure (CRF).

METHODS

We monitored for 2 years the erythropoietin (EPO) requirement in patients with advanced CRF (creatinine clearance < or =25 mL/min), randomized to either low protein diet (LPD) group (0.6 g/kg body weight/day, N = 10) or very low protein diet (VLPD) group (0.3 g/kg body weight/day, N = 10) supplemented with a mixture of ketoanalogs and essential amino acids, both kept at target hemoglobin levels.

RESULTS

The achieved protein intake after 6 months was 0.79 +/- 0.02 g/kg body weight/day and 0.50 +/- 0.02 g/kg body weight/day in LPD and VLPD, respectively; such a difference was maintained up to the end of follow up. The final hemoglobin values did not differ from the basal values in either group (11.5 +/- 0.2 g/dL and 11.5 +/- 0.3 g/dL). EPO dose, that was similar at baseline (62.4 +/- 9.6 UI/kg body weight/week and 61.8 +/- 8.8 UI/kg body weight/week subcutaneously), remained unchanged in LPD but progressively decreased in VLPD down to the final value of 41.2 +/- 7.0 UI/kg body weight/week (P < 0.0001 vs. basal and LPD). VLPD was associated with a decrease of urinary excretion and serum levels of urea nitrogen and phosphate; however, EPO requirement was not correlated with the changes of these parameters. On the contrary, the variation of EPO dose directly correlated with the modification of parathyroid hormone (PTH) levels, that diminished from 229 +/- 55 pg/mL to 118 +/- 16 pg/mL (P < 0.0001) in VLPD and did not change in LPD.

CONCLUSION

In patients with advanced CRF, an effective decrease of protein intake of 0.3 g/kg body weight/day induces a reduction of about 35% of the EPO dose required to maintain the target hemoglobin levels. This effect appears dependent on the correction of a moderate secondary hyperparathyroidism.

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.

Prevalence and prognostic significance of malnutrition in chronic renal insufficiency

OBJECTIVE

Malnutrition is present in a significant proportion of patients commencing dialysis. However, the prevalence and prognostic significance of malnutrition within the chronic renal insufficiency (CRI) population before the initiation of dialysis is poorly characterized. The aim of this study was to determine the prevalence and prognostic significance of malnutrition in an unselected group of patients with CRI.

DESIGN

Cohort analytic study.

SETTING

Ambulatory care practice of a university teaching hospital.

PATIENTS

Fifty patients with CRI (serum creatinine concentration > or = 1.7 mg/dL) were enrolled. Patients with a recent acute illness, nephrotic syndrome, intercurrent steroid therapy, gastrointestinal disease, or other severe organ failure that may have independently influenced nutritional status were excluded.

INTERVENTION

At baseline, patients had a nutritional assessment consisting of subjective global assessment (SGA), measurement of body mass index (BMI), midarm circumference (MAC), serum albumin concentration, total lymphocyte count, and single frequency bioelectrical impedance analysis. Patients received standard medical care and were followed prospectively at quarterly intervals for 12 months.

RESULTS

At baseline assessment, 28% of patients had evidence of malnutrition by SGA criteria. The malnourished group of patients had a significantly lower creatinine clearance (18.9 +/- 9.8 v 36.5 +/- 14.0 mL/min/1.73 m(2), mean +/- SD, P <.001), glomerular filtration rate (20.7 +/- 10.9 v 28.5 +/- 12.5 mL/min/1.73 m(2), P =.04), BMI (22.7 +/- 2.9 v 29.0 +/- 5.0 kg/m(2)), and MAC (24.3 +/- 4.9 v 30.7 +/- 4.8 cm, P <.001), but there were no differences in serum albumin concentration or total lymphocyte count between the groups. At the 12-month follow-up, there was significantly increased mortality (21% v 3%, P =.04), composite endpoint of death or dialysis (50% v 11%, P =.02), and likelihood of acute hospitalization (78% v 23%, P =.001) in the malnourished group. A significant association was observed between baseline nutritional status and subsequent admission to hospital and baseline glomerular filtration rate and progression to end-stage renal failure.

CONCLUSION

These data suggest that SGA provides a useful means of assessing nutritional status and is helpful in identifying patients with increased risk of morbidity and mortality in the setting of CRI.

Are supplemented low-protein diets nutritionally safe?

In patients with chronic renal failure (CRF), the reduction of dietary protein intake may correct uremic symptoms, slow the rate of progression of renal failure, and delay the onset on dialysis. Concerns have been made on the nutritional consequences of protein-restricted diets. Over 15 years, 239 patients were treated with a very-low-protein diet providing 0.3 g vegetable protein/kg/day supplemented (SLPD) with essential amino acids and keto analogs. Many adverse consequences of uremia were corrected by this regimen, such as metabolic acidosis, secondary hyperparathyroidism, resistance to insulin, decreased Na(+)-K(+)-ATPase activity. A joint physician-dietitian monitoring contributed to the maintenance or obtention of a satisfactory nutritional status, even in patients at risk, diabetics, patients with the nephrotic syndrome and with renal allograft chronic rejection. The outcome of these patients when treated by hemodialysis or transplantation was favorable, their nutritional status being preserved. Results from the present study and results of other studies show that SLPD can be used in patients with advanced CRF without adverse effects in carefully selected and monitored patients.

Late initiation of dialysis among women and ethnic minorities in the United States

The ideal timing of initiation of renal replacement (RRT) therapy has been debated. It is currently recommended that RRT be instituted once the GFR falls below 10.5 ml/min per 1.73 m(2), unless edema-free body weight is stable or increased, the normalized protein nitrogen appearance rate is 0.8 g/kg per d or greater, and there are no clinical signs or symptoms of uremia. However, the mean estimated GFR at initiation of dialysis in the United States is 7.1 ml/min per 1.73 m(2). Factors that are associated with timing of initiation of dialysis in the United States are not clear. A cross-sectional study was performed to determine the factors that are associated with late initiation of dialysis as defined by GFR at initiation of less than 5 ml/min per 1.73 m(2) among patients who began dialysis in the United States between 1995 and 1997. Data were obtained from the U.S. Renal Data System, and GFR was estimated using the formula derived from the Modification of Diet in Renal Disease Study. Twenty-three percent of patients started dialysis late. In the multivariate analysis, women (odds ratio [OR] = 1.70), Hispanics and Asians (OR = 1.47 and 1.66, respectively, compared with Caucasians), uninsured patients (OR = 1.55 compared with private insurance), and employed patients (OR = 1.20) were more likely to start dialysis late. Patients with diabetes, cardiac disease, peripheral vascular disease, and poor functional status were less likely to start dialysis late compared with patients without these comorbid conditions. Certain nonclinical patient characteristics, notably female gender, race, and lack of insurance, are related to an increased likelihood of late initiation of dialysis. These factors may reflect reduced access to care. Additional studies are indicated to determine the potential impact of reduced access to care and whether late initiation of dialysis results in adverse clinical and economic outcomes among patients with end-stage renal disease in the United States.

Treatment of advanced renal failure: low-protein diets or timely initiation of dialysis?

Until 1996, no guidelines existed for the initiation of dialysis in patients with progressive renal failure. The publication of the National Kidney Foundation-Dialysis Outcome Quality Initiative guidelines has generated a debate on the management of advanced renal failure and the role of low-protein diets (LPDs). We performed a review of the literature to identify articles on the initiation of dialysis and LPDs, particularly those since 1996. Delayed referral of patients is widespread in both the United States and Europe, and almost 25% of patients are started on dialysis at a glomerular filtration rate (GFR) of <5 mL/min/1.73 m2. There is a high prevalence of malnutrition at the time of first dialysis, which progressively improves upon initiation of dialysis. There is no evidence regarding the efficacy or safety of LPDs in nondiabetic patients younger than 70 years old [approximately 40% of U.S. incident end-stage renal disease (ESRD) patients] and in diabetics with GFR <25 mL/min/1.73 m2 (>40% of incident U.S. ESRD). In nondiabetics who are younger than 70 years old, adherence to LPD for four to five years can be estimated to result in a delay in dialysis by 6 to 11 months. However, suboptimal energy intake is widespread in advanced renal failure, which declines further upon institution of LPD. Even nutritionally sound patients develop subclinical nutritional decline despite intense counseling. There are no data on the efficacy or safety of LPD in subgroups that constitute approximately 80% of incident ESRD patients. Concerns still exist regarding their nutritional safety in the remainder. Initiation of dialysis results in improved nutritional status and should be considered in a timely fashion.

Randomized double-blind trial of oral essential amino acids for dialysis-associated hypoalbuminemia

BACKGROUND

Hypoalbuminemia is associated with substantial morbidity and mortality in dialysis patients.

METHODS

Subjects with a mean three-month prestudy serum albumin of 3.8 g/dL or less and who demonstrated >/=90% compliance during a two-week run-in period were randomized to 3.6 g of essential amino acids (EAAs) or placebo three times daily with meals for three months. Randomization was stratified by dialysis modality and by severity of the hypoalbuminemia. The primary study outcome was change in the average of three monthly serum albumin measurements between baseline and follow-up.

RESULTS

Fifty-two patients were randomized; 47 patients (29 hemodialysis and 18 peritoneal dialysis) met the predetermined primary analysis criteria. The mean compliance rates averaged 75, 70, and 50% at months 1, 2, and 3, respectively, and were similar for EAAs and placebo. Serum albumin in the hemodialysis patients, EAA versus placebo, improved [(mean +/- SE) 0.22 +/- 0.09 g/dL, P = 0.02]. Changes in peritoneal dialysis patients were not significant (0.01 +/- 0.15 g/dL), but approached significance for the total study group (0.14 +/- 0.08 g/dL, P = 0.08). Patients in the very low albumin strata (<3.5 g/dL) improved more than those in the low albumin strata (3.5 to 3.8 g/dL, P < 0.01). There was a significant correlation (r = 0.83, P = 0.001) within the hemodialysis EAA group between the baseline C-reactive protein level and improvement in serum albumin. Improvements were also seen in grip strength and SF-12 mental health score, but not in serum amino acid levels, SF-12 physical health score, or anthropometric measurements.

CONCLUSIONS

Oral EAAs induce a significant improvement in the serum albumin concentration in hemodialysis but not peritoneal dialysis subjects. Further study of their long-term effects on morbidity and mortality is warranted.

Nutrition and outcome on renal replacement therapy of patients with chronic renal failure treated by a supplemented very low protein diet

Protein-restricted diets are prescribed in patients with chronic renal failure (CRF) to alleviate uremic symptoms and to slow the progression of CRF. The potential deleterious effects of protein restriction on nutritional status and clinical outcome of patients with CRF have raised concern. In this study, data were collected from 1985 to 1998 on 239 consecutive patients (age 50.2 +/- 15.6 yr) with advanced CRF (GFR 13.1 +/- 4.8 ml/min) to whom a supplemented very low protein diet (SVLPD) providing 0.3 g protein, 35 kcal, and 5 to 7 mg of inorganic phosphorus per kg per day was administered for a mean duration of 29.6 +/- 25.1 mo. The diet was supplemented with essential amino acids and ketoanalogs, calcium carbonate, iron, and multivitamins. During SVLPD, protein intake decreased from 0.85 +/- 0.23 to 0.43 +/- 0.11 g/kg per d, and body mass index and serum albumin concentration remained unchanged overall. Fourteen patients died during SVLPD; death was unrelated to nutritional parameters. Hemodialysis was initiated after SVLPD in 165 patients at a mean GFR of 5.8 +/-1.5 ml/min. During an average of 54 mo on hemodialysis, mortality was low (2.4% after 1 yr) and correlated to age only, not to nutritional parameters observed at the end of SVLPD. Similar results were obtained in 66 transplanted patients (12 were not dialyzed before transplantation). SVLPD can be safely used in patients with CRF without adverse effects on the clinical and nutritional status of the patients. Due to the preservation of nutritional status and the correction of uremic symptoms, the initiation of dialysis was deferred in these patients. The outcome of patients on renal replacement therapy is not affected by prior treatment with SVLPD during the predialysis phase of CRF.

Dietary protein restriction and the progression of chronic renal disease: what have all of the results of the MDRD study shown? Modification of Diet in Renal Disease Study group

The Modification of Diet in Renal Disease (MDRD) Study was the largest randomized clinical trial to test the hypothesis that protein restriction slows the progression of chronic renal disease. However, the primary results published in 1994 were not conclusive with regard to the efficacy of this intervention. Many physicians interpreted the failure of the MDRD Study to demonstrate a beneficial effect of protein restriction over a 2- to 3-yr period as proving that this therapy does not slow disease progression. The authors believe that this viewpoint is incorrect, and is the result of misinterpretation of inconclusive evidence as evidence in favor of the null hypothesis. Since then, numerous secondary analyses of the MDRD Study have been undertaken to clarify the effect of protein restriction on the rate of decline in GFR, urine protein excretion, and onset of end-stage renal disease. This review describes some of the principles of secondary analyses of randomized clinical trials, presents the results of these analyses from the MDRD Study, and compares them with results from other randomized clinical trials. Although these secondary results cannot be regarded as definitive, the authors conclude that the balance of evidence is more consistent with the hypothesis of a beneficial effect of protein restriction than with the contrary hypothesis of no beneficial effect. Until additional data become available, physicians must continue to make recommendations in the absence of conclusive results. The authors suggest that physicians incorporate the results of these secondary analyses into their interpretation of the findings of the MDRD Study.

Outcome of nutritional status and body composition of uremic patients on a very low protein diet

Concern has been raised about the nutritional adequacy of a very low protein diet (VLPD). Monthly clinical evaluation by a physician and dietitian and quarterly dietary records, anthropometric measurements, blood testing, and dual energy X-ray absorptiometry (DEXA) were used to assess the course of nutritional status for 1 year in 10 clinically stable patients (six men, four women; age, 57.1 +/- 9.3 years) with advanced chronic renal failure (mean glomerular filtration rate, 13.2 +/- 4.8 mL/min/1.73 m(2)). These patients received a VLPD providing 0.3 g/kg/d of protein and were supplemented with amino acids and ketoanalogues. Conventional nutritional markers remained unchanged after 1 year of the VLPD. However, during the same period, whole-body DEXA showed a significant decrease in lean tissue from 46.2 +/- 10.2 to 45.0 +/- 9. 8 kg (P < 0.02); limb-trunk lean tissue ratio was reduced from 0.86 +/- 0.12 to 0.82 +/- 0.12 (P < 0.02), total-body fat increased from 20.0 +/- 6.9 to 21.4 +/- 7.0 kg (P < 0.05), and the percentage of total-body fat increased from 29.2% +/- 8.7% to 31.7% +/- 8.8% (P < 0.03). These different modifications occurred abruptly during the first 3 months, then stabilized or slightly improved thereafter. These mild changes do not appear to be deleterious given the favorable long-term outcome of these patients, even after they began treatment by dialysis or after renal transplantation.

Can renal replacement be deferred by a supplemented very low protein diet?

Patients with chronic renal failure are commonly started on renal replacement therapy (RRT) as soon as (or, in some centers, before) the usual criteria for severity are met, i.e., GFR <10 ml/min for nondiabetic patients and <15 ml/min for diabetic patients. To determine whether RRT can safely be deferred beyond this point, adults with all types of chronic renal failure who met these criteria on presentation (23 patients) or who reached these levels of severity during treatment (53 patients) were managed conservatively until RRT was judged necessary by their chosen dialysis or transplantation team, without input into this decision from the present authors. Patients were prescribed a very low protein diet (0.3 g/kg) plus supplemental essential amino acids and/or ketoacids and followed closely. The intervals between the time at which GFR became less than 10 ml/min (15 ml/min in diabetic patients) and the date at which renal replacement therapy was started were used as estimates of renal survival on nutritional therapy. Kaplan-Meier analysis showed median renal survival of 353 d. Acidosis and hypercholesterolemia were both predictive of shorter renal survival. Signs of malnutrition did not develop. Final GFR averaged 5.6 +/- 1.9 ml/min. Two patients died; thus, annual mortality was only 2.5%. Hospitalizations totaled 19 in 93 patient-years of treatment, or 0.2 per year. Thus, these well motivated patients with GFR <10 ml/min (<15 ml/min in diabetic patients) were safely managed by diet and close follow-up for a median of nearly 1 yr without dialysis. It is concluded that further study of this approach is indicated.

Effects of low-protein diet on carbohydrate metabolism and energy expenditure

Low-protein diets (LPD), which are prescribed for uremic patients to slow the progression of chronic renal failure, theoretically may exacerbate disorders of carbohydrate metabolism that are frequently observed in these patients because increased carbohydrate rations are required to maintain a sufficient caloric intake. No such exacerbation actually occurs. Glucose tolerance has been shown to improve after 3 months of a diet affording .3 g protein/kg body weight supplemented with essential amino acids and ketoanalogs with carbohydrates accounting for 67% of the total energy intake. Hyperinsulinemic euglycemic clamp studies show that this amelioration is linked with an increase in insulin sensitivity, which is also observed in uremic diabetic patients on this diet. The improvement in glucose tolerance involves the insulin sensitivity of endogenous glucose production, glucose oxidative disposal, and its nonoxidative disposal. Besides these effects, LPD increases the metabolic clearance rate of insulin and causes blood insulin levels to decrease. LPD's low acid load and phosphorus content, the reduced synthesis of uremic toxins derived from alimentary protein, or both may explain these effects, which are indirectly protective against atherosclerosis. However, the significant increase in resting energy production after 3 months on LPD justifies strict monitoring of nutritional status and caloric intake.

Effect of dietary protein restriction on nutritional status in the Modification of Diet in Renal Disease Study

The safety of dietary protein and phosphorous restriction was evaluated in the Modification of Diet in Renal Disease (MDRD) Study. In Study A, 585 patients with a glomerular filtration rate (GFR) of 25 to 55 ml/min/1.73 m2 were randomly assigned to a usual-protein diet (1.3 g/kg/day) or a low-protein diet (0.58 g/kg/day). In Study B, 255 patients with a GFR of 13 to 24 ml/min/1.73 m2 were randomly assigned to the low-protein diet or a very-low-protein diet (0.28 g/kg/day), supplemented with a ketoacid-amino acid mixture (0.28 g/kg/day). The low-protein and very-low-protein diets were also low in phosphorus. Mean duration of follow-up was 2.2 years in both studies. Protein and energy intakes were lower in the low-protein and very-low-protein diet groups than in the usual-protein group. Two patients in Study B reached a "stop point" for malnutrition. There was no difference between randomized groups in the rates of death, first hospitalizations, or other "stop points" in either study. Mean values for various indices of nutritional status remained within the normal range during follow-up in each diet group. However, there were small but significant changes from baseline in some nutritional indices, and differences between the randomized groups in some of these changes. In the low-protein and very-low-protein diet groups, serum albumin rose, while serum transferrin, body wt, percent body fat, arm muscle area and urine creatinine excretion declined. Combining patients in both diet groups in each study, a lower achieved protein intake (from food and supplement) was not correlated with a higher rate of death, hospitalization or stop points, or with a progressive decline in any of the indices of nutritional status after controlling for baseline nutritional status and follow-up energy intake. These analyses suggest that the low-protein and very-low-protein diets used in the MDRD Study are safe for periods of two to three years. Nonetheless, both protein and energy intake declined and there were small but significant declines in various indices of nutritional status. These declines are of concern because of the adverse effect of protein calorie malnutrition in patients with end-stage renal disease. Physicians who prescribe low-protein diets must carefully monitor patients' protein and energy intake and nutritional status.

Protein intake and the nutritional status in patients with pre-dialysis chronic renal failure on unrestricted diet

OBJECTIVES

Malnutrition is known to be highly associated with morbidity and mortality in dialysis patients. Malnutrition may begin to develop in patients with chronic renal failure(CRF) before they need dialysis. In this study, the nutritional status of patients with moderate to severe CRF on unrestricted diet was evaluated.

METHODS

We measured dietary protein intake (DPI, g/kg/day) in 64 patients with CRF and 42 normal controls(N). Nutritional indices such as serum albumin(SA, g/dl), transferrin(TF, mg/dl), prealbumin(PA, mg/dl) and insulin-like growth factor-1(IGF-1, ng/ml) were measured to evaluate the visceral proteins, and creatinine-height index(C-H, g/d/m) to evaluate the somatic proteins.

RESULTS

Mean DPI was 0.80 +/- 0.27(S.D) in CRF and 1.07 +/- 0.30 in N(p < 0.0001). DPI was lower than 0.6 in 15 CRF patients(23%). Serum albumin, transferrin and C-H were significantly lower in CRF patients than in N(p < 0.01). In patients with CRF, nutritional indices were significantly worse with lower DPI(< 0.6 g/kg/d, n = 15) than higher DPI(> 0.6 g/kg/d, n = 49)(SA 2.9 +/- 0.7 vs. 3.6 +/- 0.8, p < 0.005; TF 147 (134-179) vs. 220(182-264), p < 0.0005; PA 24 +/- 8 vs. 32 +/- 9, p < 0.001; IGF-1 123 (66-261) vs. 226(140-344), p < 0.05; C-H 0.52 +/- 0.15 vs. 0.87 +/- 0.23, p < 0.0001). CRF patients with nephrotic range proteinuria (> 3.5 g/d, n = 19) had lower SA (2.8 +/- 0.6 vs. 3.8 +/- 0.8, p < 0.0001) and PA(27 +/- 9 vs. 32 +/- 9, p < 0.05). CRF patients with diabetes mellitus (n = 20) showed worse nutrition than non-diabetic patients(SA 2.8 +/- 0.6 g/dl vs. 3.8 +/- 0.8 g/dl, p < 0.0001; TF 176 mg/dl(148-214) vs. 220 mg/dl(175-266), p < 0.05; PA 24 +/- 10 mg/dl vs. 33 +/- 8 mg/dl, p < 0.0005; IGF-1 138 ng/ml(69-269) vs 231 ng/ml(140-364), p < 0.05; C-H 0.66 +/- 0.23 vs. 0.85 +/- 0.5, p < 0.005).

CONCLUSION

A significant protein malnutrition prevails in patients with pre-dialysis CRF on unrestricted diet, especially with low protein intake. The effort to detect and correct malnutrition should be made in patients with CRF even before initiation of maintenance dialysis.

Use of dietetic-specific nutritional diagnostic codes in clinical reasoning relevant to the nutritional management of core clinical outcome indicators in hemodialysis patients

The Health Care Financing Agency (HCFA) has recommended conscientious monitoring of four core outcome indicators (anemia, albumin, treatment adequacy, and hypertension) by the end stage renal disease (ESRD) health care team. Dietetic-specific nutritional diagnostic categories (D-S NDCs) can be a powerful tool in guiding renal nutrition specialists through the clinical reasoning required to diagnose and clinically correct nutrition-related problems in hemodialysis (HD) patients. The purpose of this article is to portray one clinician's dual use of D-S NDCs to identify the nutritional problem responsible for poor performance and determine nutritionally treatable causes. Although four indicator-specific sets of D-S NDCs commonly used in the nutritional assessment of anemia, albumin, treatment adequacy and hypertension were identified and referenced, seven codes were consistently repeated. These D-S NDCs were (1) altered nutritional biochemistry integrity; (2) absence of/limited nutritional service; (3) deficit in nutrition knowledge; (4) imbalance of nutrient/fluid; (5) nutrition misinformation; (6) toxicity of nutrient/nutrient end-product; and (7) possibility of developing a specific disease. Thus, in ESRD, use of D-S NDCs shows the implicit role of the registered dietitian in disease prevention, management of altered nutrient disposition, and patient education.

Role of nutrition in prevention of the progression of renal disease

In rats with renal disease, low-protein diets slow the decline in renal function, histologic damage, and mortality. Low-protein (and phosphorus) diets can also ameliorate uremic symptoms, secondary hyperparathyroidism, and metabolic acidosis in patients with chronic renal failure. Albeit controversial, evidence also suggests that dietary protein restriction can slow the rate of progression of renal failure and the time until end-stage renal failure. These dietary regimens appear to be safe and patients with chronic renal failure are able to activate normal compensatory mechanisms designed to conserve lean body mass when dietary protein intake is restricted. When low-protein diets are prescribed, patients should be closely monitored to assess dietary compliance and to ensure nutritional adequacy. Evidence that the spontaneous intake of dietary protein decreases in patients with progressive chronic renal failure who consume unrestricted diets should not be construed as an argument against the use of low-protein diets. Rather, it is a persuasive argument to restrict dietary protein intake in order to minimize complications of renal failure while preserving nutritional status.

Treatment of nephrotic adults with a supplemented, very low-protein diet

Optimal dietary protein intake for adults with the nephrotic syndrome has not been established; very low-protein diets are believed to be contraindicated. Sixteen patients with the nephrotic syndrome were nevertheless prescribed a very low protein diet (0.3 g/kg) supplemented by 10 to 20 g/d essential amino acids (or, in a few cases, ketoacids) for an average of 10 months (range, 1 to 36 months). In 11 patients with initial glomerular filtration rates (GFRs) < or = 30 mL/min/3 m2 of height (ht)2, significant but modest improvement was seen (on the average) in proteinuria, serum albumin, and serum cholesterol; all 11 eventually went on to dialysis. The other five patients, with initial GFRs of 32 to 69 ml/min/3 m2 of ht2, had either focal segmental glomerulosclerosis, diabetic nephropathy, or, in one patient, both. The nephrotic syndrome associated with these disorders rarely remits spontaneously. However, during the following 3 to 15 months mean proteinuria decreased from 9.3 to 1.9 g/d, mean serum albumin increased from 2.5 g/dL to 3.8 g/dL, and mean serum cholesterol decreased from 415 mg/dL to 255 mg/dL (all P < 0.001). The GFR either remained constant or increased. Four of these five patients have resumed normal or nearly normal diets and remain in remission or near-remission for 6 to 24 months. We conclude that severe protein restriction plus an essential amino acid supplement may induce prolonged remission in adults with the nephrotic syndrome provided that GFR is not severely reduced. The mechanism of this paradoxical response to protein restriction remains to be determined.

Nutrition in end-stage renal disease

In summary, it is evident that malnutrition is highly prevalent in ESRD patients. This is clearly related to multiple factors encountered during the pre-dialysis stage, as well as during maintenance dialysis therapy. A body of evidence highlights the existence of relationship between malnutrition and outcome in this patient population. Several preliminary studies suggest that interventions to improve the poor nutritional status of the ESRD patients may actually improve the expected outcome in these patients, although their long-term efficacy is not well established. It is therefore important to emphasize that malnutrition is a major co-morbid condition in the ESRD population and that the nutritional status and the treatment parameters of these patients should be altered to improve not only the mortality outcome of ESRD patients but also their quality of life.

Low-protein diets in the treatment of chronic renal failure

Dietary protein restriction is an established method of preventing the symptoms of uremia but three questions should be asked before beginning this type of therapy: Will the diet maintain adequate nutrition? Can compliance be monitored? Will the low-protein diet prevent uremic symptoms and change the course of the disease? There are positive answers to these questions. Recently it has been shown that the metabolic acidosis associated with kidney failure causes catabolism by increasing the degradation of muscle protein and of essential amino acids. The mechanism for these responses includes increased mRNAs encoding enzymes involved in catabolic pathways. Activation of these pathways would impair the ability of patients to respond to a low-protein diet because the ability to reduce the oxidation of essential amino acids and degradation of protein would be limited.