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

Abstract

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

Low‐protein diet for conservative management of chronic kidney disease: a systematic review and meta‐analysis of controlled trials

“…The applicability of many nutritional interventions and their effects on outcomes in patients with moderate to advanced CKD, including those with protein‐energy wasting or at high risk of its development, has not been well studied. The challenge remains as to how to reconcile low dietary protein intake—to avoid or delay dialysis initiation—with adequate nutrient intake and nutritional therapy while insuring favourable nutritional status and to avoid or correct protein‐energy wasting 13. The field lacks an up‐to‐date systematic review and meta‐analysis study on the subject with a focus on the conservative management of CKD.…”

Implementation of a continuous quality improvement program reduces the occurrence of peritonitis in PD

“…9 Inadequate protein intake and loss of nutrients are major causes of malnutrition. 10 We evaluated the impact of nutritional status and intestinal function on the incidence of peritonitis in patients with CAPD, and compared the nutrition and inflammatory parameters between the peritonitis group and the non-peritonitis group during the same period. We found that erythrocyte sedimentation rates and C-reaction protein levels were significantly elevated and serum albumin levels were significantly reduced in the peritonitis group compared with the non-peritonitis group, and no significant differences in hemoglobin levels between the peritonitis and non-peritonitis groups.…”

The Serum Irisin Level in Non-Diabetic Patients with Chronic Kidney Disease

“…Protein energy wasting occurs in the early and middle stages of CKD, and is characterized by loss of muscle and fat tissue, and a decrease in body protein mass and energy reserve (1). According to studies performed in numerous countries, metabolic imbalance and abnormal energy expenditure varies (18%-80%) in CKD patients according to the stage of disease (2).…”