Philippe Chauveau

Nutrition and chronic kidney disease.

The incidence of malnutrition disorders in chronic kidney disease (CKD) appears unchanged over time, whereas patient-care and dialysis techniques continue to progress. Despite some evidence for cost-effective treatments, there are numerous caveats to applying these research findings on a daily care basis. There is a sustained generation of data confirming metabolic improvement when patients control their protein intake, even at early stages of CKD. A recent protein-energy wasting nomenclature allows a simpler approach to the diagnosis and causes of malnutrition. During maintenance dialysis, optimal protein and energy intakes have been recently challenged, and there is no longer an indication to control hyperphosphatemia through diet restriction. Recent measurements of energy expenditure in dialysis patients confirm very low physical activity, which affects energy requirements. Finally, inflammation, a common state during CKD, acts on both nutrient intake and catabolism, but is not a contraindication to a nutritional intervention, as patients do respond and improve their survival as well as do noninflamed patients.

Factors influencing survival in hemodialysis patients aged older than 75 years: 2.5-year outcome study

The incidence of malnutrition is widely held to be greater in the elderly, but this specific factor has not been extensively studied in elderly dialysis patients. In a 30-month follow-up prospective study, we evaluated the role of nutrition on the outcome of 290 stable hemodialysis (HD) outpatients aged older than 75 years followed up in 20 French HD centers (167 men, 123 women; age, 79.8 +/- 4.2 years; previous time on dialysis, 41 +/- 38 months). On the same day in January 1996, predialysis and postdialysis blood samples were collected according to recommended procedures for dialysis quantification. Normalized protein catabolic rate, dialysis adequacy parameters, and estimation of lean body mass (LBM; expressed as observed/expected LBM values [obs/exp LBM]) were computed from predialysis and postdialysis urea and creatinine levels. Overall survival rates were 80% and 65% after 1 and 2 years of follow-up, respectively, and were significantly less in patients with the lower quartile of obs/exp LBM. In univariate analysis using the Cox proportional hazards model, survival was significantly influenced by age, albumin level, prealbumin level, body mass index, and diabetes, but not by sex, Kt/V, duration of dialysis, cholesterol level, hemoglobin level, or obs/exp LBM. In multivariate analysis, no variable remained significant. Cardiovascular mortality accounted for 52.1% of the patient deaths. We conclude that in elderly HD patients, malnutrition influences overall survival despite adequate dialysis treatment.

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

BACKGROUNDnThe 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.nnnOBJECTIVEnWe evaluated the long-term clinical outcome during maintenance dialysis and/or transplantation in patients who previously received a supplemented very-low-protein diet.nnnDESIGNnWe 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).nnnRESULTSnThe 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.nnnCONCLUSIONSnThe 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.

Are ghrelin and leptin involved in food intake and body mass index in maintenance hemodialysis

OBJECTIVESnBoth leptin and ghrelin (in the forms of acyl ghrelin and des-acyl ghrelin) are involved in food intake, and appear to be dysregulated in chronic kidney disease. This study describes plasma leptin, acyl, and des-acyl ghrelin concentrations in relation to protein intake and body mass index (BMI) in hemodialysis (HD) patients.nnnDESIGNnThis was a cross-sectional study.nnnSETTINGnThis study was conducted during the baseline phase of the French multicenter Influence of a High-Flux Dialyzer on Long-Term Leptin Levels Study.nnnPATIENTSnWe studied 125 HD patients (aged 72.5+/-11.7 years; 59% males).nnnMAIN OUTCOME MEASUREnBlood samples were collected during fasting, and before a regular HD session. Plasma ghrelin and leptin were evaluated. The protein equivalents of total nitrogen appearance and BMI were calculated.nnnRESULTSnPatients demonstrated elevated serum leptin (48.0+/-49.0 ng/mL) and des-acyl ghrelin (646.6+/-489.5 pg/mL) levels, and low acyl ghrelin levels (29.8+/-58.5 pg/mL), according to normal values. Acyl ghrelin was negatively correlated with C-reactive protein (r=-0.34, P < .001). The des-acyl to acyl ghrelin ratio was negatively correlated with protein intake, as estimated by normalized Protein Nitrogen Appearance (r=-0.22, P=.01). Serum leptin exhibited its well-described positive correlation with BMI and waist circumference, but the other hormones did not.nnnCONCLUSIONSnThis study reports high des-acyl ghrelin and leptin levels and low acyl ghrelin levels in HD patients, a finding potentially associated with inflammation and food intake.

Adherence to ketoacids/essential amino acids-supplemented low protein diets and new indications for patients with chronic kidney disease

BackgroundLow protein diets (LPD) have long been prescribed to chronic kidney disease patients with the goals of improving metabolic abnormalities and postpone the start of maintenance dialysis.MethodsWe reviewed the recent literature addressing low protein diets supplemented with ketoacids/essential aminoacids prescribed during chronic kidney disease and their effects on metabolic, nutritional and renal parameters since 2013.ResultsWe show new information on how to improve adherence to these diets, on metabolic improvement and delay of the dialysis needs, and preliminary data in chronic kidney disease associated pregnancy. In addition, data on incremental dialysis have been reviewed, as well as potential strategies to reverse protein energy wasting in patients undergoing maintenance dialysis.ConclusionThese recent data help to better identify the use of low protein diets supplemented with ketoacids/essential aminoacids during chronic kidney disease.

As we grow old: nutritional considerations for older patients on dialysis

The number of older people on dialysis is increasing, along with a need to develop specialized health care to manage their needs. Aging-related changes occur in physiological, psychosocial and medical aspects, all of which present nutritional risk factors ranging from a decline in metabolic rate to assistance with feeding-related activities. In dialysis, these are compounded by the metabolic derangements of chronic kidney disease (CKD) and of dialysis treatment per se, leading to possible aggravation of protein-energy wasting syndrome. This review discusses the nutritional derangements of the older patient on dialysis, debates the need for specific renal nutrition guidelines and summarizes potential interventions to meet their nutritional needs. Interdisciplinary collaborations between renal and geriatric clinicians should be encouraged to ensure better quality of life and outcomes for this growing segment of the dialysis population.

Vitamin D, a modulator of musculoskeletal health in chronic kidney disease

The spectrum of activity of vitamin D goes beyond calcium and bone homeostasis, and growing evidence suggests that vitamin D contributes to maintain musculoskeletal health in healthy subjects as well as in patients with chronic kidney disease (CKD), who display the combination of bone metabolism disorder, muscle wasting, and weakness. Here, we review how vitamin D represents a pathway in which bone and muscle may interact. In vitro studies have confirmed that the vitamin D receptor is present on muscle, describing the mechanisms whereby vitamin D directly affects skeletal muscle. These include genomic and non‐genomic (rapid) effects, regulating cellular differentiation and proliferation. Observational studies have shown that circulating 25‐hydroxyvitamin D levels correlate with the clinical symptoms and muscle morphological changes observed in CKD patients. Vitamin D deficiency has been linked to low bone formation rate and bone mineral density, with an increased risk of skeletal fractures. The impact of low vitamin D status on skeletal muscle may also affect muscle metabolic pathways, including its sensitivity to insulin. Although some interventional studies have shown that vitamin D may improve physical performance and protect against the development of histological and radiological signs of hyperparathyroidism, evidence is still insufficient to draw definitive conclusions.

Mediterranean diet as the diet of choice for patients with chronic kidney disease.

Traditional dietary management of chronic kidney disease (CKD) focuses on the quantity within the diet of energy and protein, and the restriction of single micronutrients, with little mention of dietary quality. Dietary patterns that are more plant-based, lower in meat (including processed meat), sodium and refined sugar, and have a higher content of grains and fibres are now included in multiple clinical guidelines for chronic disease prevention. The Mediterranean diet (MD) has been associated with reduced cardiovascular disease incidence in both observational and interventional studies. A wealth of evidence links MD with other beneficial effects on chronic diseases such as diabetes, obesity or cognitive health. This review examines each constituent of the classical MD and evaluates their suitability for the management of patients with CKD. We also evaluate the potential hyperkalaemia risk of increasing fruit and vegetable intake. Overall, a decrease in net endogenous acid production and increase in fibre may lead to a better control of metabolic acidosis. This, together with other putative favourable effects of MD on endothelial function, inflammation, lipid profile and blood pressure, provide mechanistic pathways to explain the observed reduced renal function decline and improved survival in CKD patients adhering to an MD.

Dénutrition et techniques de dialyse

Resume La prevalence de la denutrition est elevee en dialyse. Aux facteurs de denutrition lies a linsuffisance renale, se surajoutent ceux associes a la technique. Une quantite de dialyse inadequate aggrave lanorexie et la denutrition. En dehors des complications liees a la maladie, les facteurs hypercataboliques associent acidose, deperdition en nutriments et en proteines, facteurs inflammatoires secondaires a linteraction sangmembrane en hemodialyse ou a la presence de liquide de dialyse peritoneale. Les apports en calories et en proteines doivent etre augmentes par rapport aux apports prescrits chez les patients non dialyses. Les index de dialyse adequate et de denutrition doivent etre mesures regulierement, et adaptes a la technique utilisee. Le type de dialyse, la quantite et la qualite doivent etre adaptes a letat clinique du patient.

Amino Acids and Keto Acids in the Treatment of Chronic Renal Failure

Clinical trials using very low protein supply supplemented with amino acid or keto acid preparations have shown the possibility of slowing the rate of decline of renal function in patients with advanced chronic renal failure together with preservation of nutritional status. The possible mechanisms by which this effect is obtained are reviewed. The potential advantages of keto acids upon amino acids, the optimal composition of the preparations used, and the best time to start treatment in chronic uremics are discussed. Projection of recent data indicate that a prolongation of renal autonomy of about 4 years instead of a spontaneous duration of 15 months until dialysis can be expected using keto acid treatment if started when plasma creatinine reaches 500 mumol/l.