The malnutrition and inflammation axis in pediatric patients with chronic kidney disease

Screening for protein energy wasting in children with chronic kidney disease using dual energy x-ray absorptiometry as an additional tool

BACKGROUND

The current diagnosis of protein energy wasting (PEW) is based on scoring systems that lack precision in measuring muscle deficits. We undertook this cross-sectional study to determine the prevalence of PEW in children with chronic kidney disease (CKD) using a scoring system that included dual energy x-ray absorptiometry (DEXA) for measuring lean body mass (LBM) and to determine the prevalence of selected markers in PEW.

METHODS

Thirty CKD and 20 healthy children (1-18 years) were evaluated for (1) reduced dietary protein intake (DPI); (2) BMI < fifth centile for height age (BMI/HA); (3) serum albumin < 3.8 g/dl, cholesterol < 100 mg/dl, or CRP > 3 mg/L; (4) LBM < fifth centile for height age [LBMr] on DEXA. PEW was scored as minimal-one parameter positive in 2/4 categories; standard-one parameter positive in 3/4 categories; or modified-standard plus height < 2 SD.

RESULTS

Twenty children with CKD (66.7%) had PEW, (5/9) 55% in CKD 3, and (15/21) 71% in advanced CKD; minimal 12, standard 1, and modified 7. LBMr was seen in 20 (100%), reduced DPI in 16 (80%), and BMI/HA in 6 (30%) children with PEW. LBMr had 100% sensitivity and BMI/HA 100% specificity. LBMr was seen in 8 who had no other criteria for PEW. None of the parameters were positive in controls (p < 0.01).

CONCLUSIONS

PEW prevalence in CKD was high. Both prevalence and severity were higher in advanced CKD. LBMr was a highly sensitive marker to detect PEW. LBMr seen in some children with CKD who were negative for other markers could represent subclinical PEW.

Estimating Total Energy Expenditure to Determine Energy Requirements in Free-Living Children With Stage 3 Chronic Kidney Disease: Can a Structured Approach Help Improve Clinical Care?

OBJECTIVE

Malnutrition and obesity are complex burdensome challenges in pediatric chronic kidney disease (CKD) management that can adversely affect growth, disease progression, wellbeing, and response to treatment. Total energy expenditure (TEE) and energy requirements in children are essential for growth outcomes but are poorly defined, leaving clinical practice varied and insecure. The aims of this study were to explore a practical approach to guide prescribed nutritional interventions, using measurements of TEE, physical activity energy expenditure (PAEE), and their relationship to kidney function.

DESIGN AND METHODS

In a cross-sectional prospective age-matched and sex-matched controlled study, 18 children with CKD (6-17 years, mean stage 3) and 20 healthy, age-matched, and gender-matched controls were studied. TEE and PAEE were measured using basal metabolic rate (BMR), activity diaries and doubly labeled water (healthy subjects). Results were related to estimated glomerular filtration rate (eGFR). The main outcome measure was TEE measured by different methods (factorial, doubly labeled water, and a novel device).

RESULTS

Total energy expenditure and PAEE with or without adjustments for age, gender, weight, and height did not differ between the groups and was not related to eGFR. TEE ranged from 1927 ± 91 to 2330 ± 73 kcal/d; 95 ± 5 to 109 ± 5% estimated average requirement (EAR), physical activity level (PAL) 1.52 ± 0.01 to 1.71 ± 0.17, and PAEE 24 to 34% EAR. Comparisons between DLW and alternative methods in healthy children did not differ significantly, except for 2 (factorial methods and a fixed PAL; and the novel device).

CONCLUSION

In clinical practice, structured approaches using supportive evidence (weight, height, BMI sds), predictive BMR or TEE values and simple questions on activity, are sufficient for most children with CKD as a starting energy prescription.

The predictive value of temporal muscle thickness measured by ultrasonography for detecting moderate to severe malnutrition in chronic hemodialysis patients

INTRODUCTION AND AIM

To determine the predictive value of temporal muscle thickness (TMT) measured by ultrasonography in the diagnosing of moderate to severe malnutrition in chronic hemodialysis (CHD) patients.

MATERIALS AND METHODS

Adult patients (> 18 years) who had been on CHD for at least 3 months were included in this cross-sectional study. Patients with infection or inflammatory disease, malignancy, malabsorption syndrome, history of surgery within the last 3 months excluded. Demographic, anthropometric, laboratory parameters, and Malnutrition Inflammation Score (MIS) test results recorded.

RESULTS

A total of 60 chronic hemodialysis (CHD) patients (median age: 66 years, 46.7% female) and 30 healthy individuals (median age: 59.5 years, 55% female) were examined. While there were no significant difference between the dry weight (70 vs 71 kg) and body mass index (BMI) (25.8 vs 26 kg/m2) of the CHD patients and healthy control group, we found that triceps skinfold thickness (TST) (16 vs 19 mm) and left and right TMT (9.6 vs 10.7 and 9.8 vs 10.9 mm) values were significantly lower in the CHD patients (p < 0.001). CHD patients were divided into two groups according to their MIS values as mild (MIS < 6) and moderate/severe malnutrition (MIS ≥ 6). Patients with moderate/severe malnutrition were older, predominantly female and with longer HD vintage. Left (8.8 vs 11 mm) and right TMT (9.1 vs 11.2 mm) values were lower in moderate/severe malnutrition group. In the correlation analysis, a negative correlation was found between TMT and age and MIS, and a positive correlation determined with dry weight, BMI, TST and serum uric acid. In the ROC curve analysis, we found that the optimal cut-off value of left and right TMT for predicting moderate/severe malnutrition were 10.05 and 10.45 mm, respectively. Multivariate regression analysis showed that HD vintage, URR, and TMT values were independently associated with moderate/severe malnutrition.

CONCLUSION

TMT value measured by ultrasonography in CHD patients can be used as a reliable, easily accessible and non-invasive diagnostic method for predicting moderate/severe malnutrition.

Association Between Adipokine Profile, Systemic Inflammation, Muscle and Protein Energy Wasting in Children With Chronic Kidney Disease

OBJECTIVES

This cross-sectional study explores the association of adipokines and interleukin-6 (IL-6) with muscle and protein energy wasting (PEW) in children with chronic kidney disease (CKD).

METHODS

We measured serum adiponectin, leptin, resistin and IL-6 in 53 patients with CKD stage 3-5. Lean tissue (LTI) and fat tissue index (FTI) were estimated by bioimpedance analysis spectroscopy. PEW was defined as muscle wasting [LTI adjusted to height age (LTI HA) z-score < -1.65 SD) and at least 2 of the following: reduced body mass [body mass index adjusted to height age (BMI HA) z-score < -1.65 SD), poor growth [height z-score < -1.88 SD], questionnaire-based decreased appetite, and serum albumin ≤3.8 g/dL.

RESULTS

PEW, observed in 8 (15.1%) patients, was more prevalent in CKD stage 5 (P = .010). Among the adipokines, adiponectin, and resistin levels were significantly higher in CKD stage 5 (P < .001, P = .005). Adiponectin was correlated to LTI HA z-score (Rs = -0.417, P = .002), leptin to FTI z-score (Rs = 0.620, P < .001), while no correlation was observed between resistin and body composition parameters. Resistin was the only adipokine correlated to IL-6 (Rs = 0.513, P < .001). After adjustment for CKD stage and patient age, PEW was associated with adiponectin and IL-6 rise by 1 μg/mL and 10 pg/mL respectively (odds ratio (OR) 1.240, 95% confidence interval (CI) 1.040, 1.478 and OR 1.405, 95% CI 1.075-1.836) but not with leptin, while resistin association with PEW lost its significance.

CONCLUSIONS

In pediatric CKD, adiponectin is associated with muscle wasting, leptin with adiposity and resistin with systemic inflammation. Adiponectin and cytokine IL-6 may serve as PEW biomarkers.

Physical performance capacity after pediatric kidney transplant and clinical parameters associated with physical performance capacity

BACKGROUND

History of chronic kidney disease and kidney transplantation is known to influence physical performance capacity. The aim of this study was to compare the physical performance of pediatric kidney transplant recipients to healthy controls and to find possible correlations between clinical parameters and physical performance capacity.

METHODS

Twenty-four pediatric kidney transplant recipients (62.5% boys) were tested at a median age of 10.8 years. Physical performance capacity was tested with a test set including six different components assessing muscle endurance, strength, speed, and flexibility. The control group consisted of 273 healthy age-matched schoolchildren. Clinical parameters were collected as part of routine follow-up protocol. The majority of patients (62.5%) had congenital nephrotic syndrome of Finnish type (CNS) as primary diagnosis, and therefore, the results of CNS recipients were compared to the other disease groups.

RESULTS

The physical performance capacity in pediatric kidney transplant recipients was lower compared to healthy controls. Surprisingly, no statistically significant correlation was found between graft function and physical performance capacity. The CNS patients scored worse than patients with other diagnoses in all test domains except for sit-and-reach and shuttle run, but the differences did not reach statistical significance.

CONCLUSION

The physical performance of pediatric kidney transplant recipients is reduced, especially in those with congenital nephrotic syndrome. Clinical parameters, including graft function, did not predict physical performance capacity, suggesting that the reduced physical performance seems to be of multivariable cause. A higher resolution version of the Graphical abstract is available as Supplementary information.

Protein Energy Wasting in Children With Chronic Kidney Disease and End-Stage Kidney Disease: An Observational Study

OBJECTIVES

Protein energy wasting (PEW), a specific nutritional comorbidity associated with increased mortality, is underrecognized in children with chronic kidney disease (CKD). The aim of this study was to determine the burden and factors associated with PEW and assess the utility of parameters used to diagnose PEW in children with CKD and End stage kidney disease (ESKD).

METHODS

Children between 2 and 18 years of age with CKD stages 2-5 were recruited over 30 months. Parameters of PEW assessed included body mass index for height, mid-upper arm circumference, height for age, appetite, serum albumin, cholesterol, transferrin, and C-reactive protein. Based on number of criteria fulfilled in each subject, PEW was further stratified as mild, standard, and modified PEW.

RESULTS

One hundred twenty-three children (male:female 3:1, 73 in CKD stages 2-4, 50 with ESKD) were recruited. PEW was observed in 58% (47% in CKD stages 2-4 vs. 73% ESKD, P = .035). Longer duration and severity of disease was associated PEW. Reduced appetite (P = .001, P = .04), low mid-upper arm circumference (P = .000, P = .006), and low body mass index for height (P = .000, P = .007) were useful criteria to diagnose PEW in CKD stages 2-4 and ESKD, while most children did not meet biochemical criteria. Inflammation observed in 47% was higher in those with ESKD [CKD stages 2-4: 72 (39%) vs. ESKD: 29 (59%), P = .02] but was associated with PEW only in CKD stages 2-4.

CONCLUSION

PEW was highly prevalent in children with CKD and ESKD. Appetite and anthropometry measures were more useful than biochemical criteria for diagnosis of PEW. Whereas inflammation was common, it was associated with PEW only in CKD stages 2-4. Pediatric CKD and ESKD may need exclusive diagnostic criteria for PEW based on anthropometry, appetite, and inflammation.

Restless Legs Syndrome in Chronic Kidney Disease: Is Iron or Inflammatory Status To Blame?

STUDY OBJECTIVES

Restless legs syndrome (RLS) is increased in pediatric chronic kidney disease (CKD). In adults without CKD, central nervous system iron deficiency is involved in RLS pathogenesis and a low serum ferritin levels is consequently an indication for initiation of iron therapy. However, children with CKD are at risk for iron deficiency and inflammation, which raises serum ferritin. We examined the role of iron deficiency and inflammation in RLS in pediatric CKD.

METHODS

This cross-sectional study examined RLS prevalence in three groups of pediatric patients with CKD: nontransplant, nondialysis CKD (estimated GFR < 60 mL/min/1.73 m²) (n = 27); renal transplant recipients (n = 65); and dialysis (n = 32). RLS was diagnosed using a validated questionnaire. Serum ferritin < 100 ng/mL or transferrin saturation < 20% defined iron deficiency. Serum high sensitivity C-reactive protein ≥ 1 mg/L defined inflammation.

RESULTS

Among 124 patients, RLS prevalence was 15.3%; this did not differ across groups. There was no significant difference in RLS prevalence between those with and without iron deficiency, defined by either reduced ferritin or transferrin. Median ferritin levels in patients with RLS tended to be higher than in those without RLS (51.2 versus 40.1 ng/mL; P = .08). Inflammation (elevated CRP) also did not differ significantly by RLS status (57.9% [with RLS] versus 41.2% [without RLS], P = .18).

CONCLUSIONS

Neither ferritin nor inflammation differentiated pediatric patients with CKD with and without RLS. This study suggests that the factors mediating the pathogenesis and, potentially, treatment, of RLS in pediatric CKD may be different from non-CKD populations.

Malnutrition in Children With Chronic Disease

Malnutrition occurs when nutrient intake does not meet the needs for normal body functions and as a consequence leads to alterations of growth and development in children. Chronic illness puts children at risk for developing malnutrition. Because of children's rapid periods of growth and development, early diagnosis, prevention, and management of malnutrition are paramount. The reasons for malnutrition in children with chronic disease are multifactorial and are related to the underlying disease and non-illness-associated factors. This review addresses the causes, evaluation, and management of malnutrition in pediatric congenital heart disease, chronic kidney disease, liver disease, and cystic fibrosis.

Measurement of iron status in chronic kidney disease

Anemia is a common complication of chronic kidney disease (CKD) in children, and dysregulation of iron homeostasis plays a central role in its pathogenesis. Optimizing iron status is a prerequisite for effective treatment of anemia. Insufficient iron can lead to inappropriate escalation of the erythropoiesis-stimulating agent (ESA) dose, which is associated with adverse outcomes. Excess iron supplementation also has negative sequelae including free radical tissue damage and increased risk of systemic infection. Notwithstanding the importance of optimizing bioavailable iron for erythropoiesis for children with advanced CKD, achieving this remains challenging for pediatric nephrologists due to the historical lack of practical and robust measures of iron status. In recent years, novel techniques have come to the fore to facilitate accurate and practical assessment of iron balance. These measures are the focus of this review, with emphasis on their relevance to the pediatric CKD population.

Growth and Nutrition in Pediatric Chronic Kidney Disease

Children with chronic kidney disease (CKD) feature significant challenges to the maintenance of adequate nutrition and linear growth. Moreover, the impaired nutritional state contributes directly to poor growth. Therefore, it is necessary to consider nutritional status in the assessment of etiology and treatment of sub-optimal linear growth. The major causes of poor linear growth including dysregulation of the growth hormone/insulin-like growth factor-I (IGF-I) axis, nutritional deficiency, metabolic acidosis, anemia, renal osteodystrophy/bone mineral disease, and inflammation. This review summarizes the causes and assessment tools of growth and nutrition while providing a summary of state of the art therapies for these co-morbidities of pediatric CKD.

Malnutrition in Chronic Kidney Disease

Patients with chronic kidney disease are at substantial risk for malnutrition, characterized by protein energy wasting and micronutrient deficiency. Studies show a high prevalence rate of malnutrition in both children and adults with chronic kidney disease. Apart from abnormalities in growth hormone-insulin like growth factor axis, malnutrition also plays a role in the development of stunted growth, commonly observed in children with chronic kidney disease. The pathogenic mechanisms of malnutrition in chronic kidney disease are complex and involve an interplay of multiple pathophysiologic alterations including decreased appetite and nutrient intake, hormonal derangements, metabolic imbalances, inflammation, increased catabolism, and dialysis related abnormalities. Malnutrition increases the risk of morbidity, mortality and overall disease burden in these patients. The simple provision of adequate calorie and protein intake does not effectively treat malnutrition in patients with chronic kidney disease owing to the intricate and multifaceted derangements affecting nutritional status in these patients. A clear understanding of the pathophysiologic mechanisms involved in the development of malnutrition in chronic kidney disease is necessary for developing strategies and interventions that are effective, and capable of restoring normal development and mitigating negative clinical outcomes. In this article, a review of the pathophysiologic mechanisms of malnutrition in chronic kidney disease is presented.

Severe Sarcopenia and Increased Fat Stores in Pediatric Patients With Liver, Kidney, or Intestine Failure

OBJECTIVES

Malnutrition and wasting predict clinical outcomes in children with severe chronic illness. Objectively calculated malnutrition in children with end-stage organ failure has not been well studied. This analysis compares children with kidney, liver or intestine failure to healthy controls to quantitate the disparity in muscle and fat stores.

METHODS

Children younger than 19 years with end-stage liver, kidney, or intestine failure and with pretransplant computed tomography (CT) imaging were selected from the transplant database. Age- and sex-matched healthy controls were selected from the trauma database. Measures of nutrition status included a scaled scoring of core muscle mass, and visceral and subcutaneous fat stores. Analysis was conducted using the pooled and individually matched subject-control differences.

RESULTS

There were 81 subjects included in the final analysis (liver [n = 35], kidney [n = 20], and intestine [n = 26]). Children with end-stage liver disease had a 23% reduction in muscle mass, a 69% increase in visceral fat, and a 29% increase in subcutaneous fat. End-stage renal disease patients had a 19% reduction in muscle mass and a 258% increase in subcutaneous fat. Intestine failure patients had a 24% reduction in muscle mass, a 30% increase in visceral fat, and a 46% increase in subcutaneous fat.

CONCLUSIONS

These results demonstrate significant sarcopenia and increased fat stores in end-stage organ failure patients, which supports the idea of an active physiologic mechanism to store fat while losing muscle mass. Sarcopenia may be related to total protein loss from a catabolic state, or from decreased synthesis (liver), wasting (kidney), or malabsorption (intestine).

Assessment of nutritional status in children with chronic kidney disease and on dialysis

Protein-energy wasting (PEW) is defined as a state of decreased body protein mass and fuel reserves (body protein and fat mass) and is a common complication of chronic kidney disease (CKD). It is multifactorial: the main causative factors are hormonal imbalances and a low nutrient intake, but low residual renal function, inadequate dialysis dose, chronic inflammation and metabolic acidosis are other important contributory factors. Adult PEW has been defined, but there is no accepted definition of pediatric PEW and consequently no precise diagnostic criteria. Assessing nutritional status in children is also complicated by the absence of a gold standard, specific abnormalities in body composition, and the slowly progressive course of the disease. The evaluation of PEW should take into account all of its pathogenetic aspects, which include dietary assessment, clinical and anthropometric assessment (based on weight, height, and body mass index), a panel of biochemical parameters, and a normalized protein catabolic rate (in the case of adolescents on hemodialysis). Bioimpedance indices can be used in individual patients on a regular basis in centers with expertise. The longitudinal follow-up data relating to the above parameters are valuable for comparing patient and normative data. Given the complex nature of PEW, only a multidisciplinary approach can provide an accurate assessment of nutritional status and its derangements in children with CKD and on dialysis.

Pretransplant serum albumin is an independent predictor of graft failure in pediatric renal transplant recipients

OBJECTIVES

To determine the prevalence of hypoalbuminemia in children listed for renal transplantation and to evaluate the effect of pretransplant hypoalbuminemia on posttransplant outcomes.

STUDY DESIGN

Retrospective cohort analysis of children receiving their first kidney transplant in the US between January 2000 and December 2010 obtained through the Organ Procurement and Transplantation Network. The primary outcome measure was time to graft failure. Cox regression analyses were used to estimate the independent effect of serum albumin on event incidence.

RESULTS

Of the 6032 children who received transplants, 308 (5.1%) had a very low serum albumin level at registration; rates of transplantation in such children varied significantly across geographic regions (χ(2), P < .001) ranging from 2.1% to 8.7%. Serum albumin was inversely associated with graft failure; each 1-g/dL increase in serum albumin was associated with a 19% reduction in risk of graft failure (adjusted hazard ratio 0.81, 95% CI 0.75-0.88, P < .001).

CONCLUSIONS

Considerable regional variation exists in the US with respect to transplantation in children with hypoalbuminemia. Severe hypoalbuminemia is an independent risk factor for graft failure. Transplant centers as well as patients need to be aware of this risk and make informed decisions regarding the optimal timing of transplantation. Whether graft failure is a consequence of the low serum albumin or the reflection of a higher inflammatory milieu remains to be explored.

Malnutrition and its association with inflammation and vascular disease in children on maintenance dialysis

BACKGROUND

Malnutrition is associated with both inflammation and atherosclerotic cardiovascular disease in adults with chronic kidney disease. We studied the prevalence of malnutrition and its possible associations with inflammation and vascular disease in children on chronic dialysis.

METHODS

Thirty-three patients on maintenance dialysis (18 peritoneal dialysis, 15 hemodialysis) and 19 age- and gender- matched healthy controls were studied. Nutritional status was assessed by anthropometric measurements including body mass index (BMI), upper arm measurements, multifrequency bioimpedance analysis (BIA) and serum levels of albumin, prealbumin, and cholesterol. Inflammation was assessed by serum levels of C-reactive protein (CRP), interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha. The carotid artery intima thickness (cIMT) was measured to assess vascular disease.

RESULTS

Compared with healthy children, patients had lower anthropometric measurements (P < 0.05) and serum albumin level (P < 0.001), and higher CRP and TNF-alpha (P = 0.030 and P = 0.007, respectively), and higher cIMT-SDS (P < 0.001). Malnutrition was present in 8 (24%) and lower BIA-based fat mass was independently associated with higher IL-6 levels (P = 0.035). An increased cIMT was present in 16 (48.5%); however, there was no difference in cIMT-SDS between patients with and without malnutrition. Carotid IMT did not show any association with nutritional indices; but positively correlated with serum IL-6 (P = 0.037), CRP (P = 0.012), and iPTH (P = 0.009), and independently associated with only iPTH (P = 0.018).

CONCLUSIONS

Children on dialysis are at an increased risk of malnutrition, inflammation, and vascular disease. Although each of these three conditions exists, there is no interaction among them all. We postulate that the malnutrition-inflammation-atherosclerosis (MIA) complex might not exist in pediatric dialysis patients.

Underweight, overweight and obesity in paediatric dialysis and renal transplant patients

BACKGROUND

The prevalence of childhood overweight is rising worldwide, but in children on renal replacement therapy (RRT) a poor nutritional status is still the primary concern. We aimed to study the prevalence of, and factors associated with, underweight and overweight/obesity in the European paediatric RRT population. Moreover, we assessed the evolution of body mass index (BMI) after the start of RRT.

METHODS

We included 4474 patients younger than 16 years from 25 countries of whom BMI data, obtained between 1995 and 2010, were available within the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry. Prevalence estimates for under- and overweight/obesity were calculated using age and sex-specific criteria of the World Health Organization (WHO, 0-1 year olds) and the International Obesity Task Force cut-offs (2-15 year olds).

RESULTS

The prevalence of underweight was 3.5%, whereas 20.8% of the patients were overweight and 12.5% obese. Factors associated with being underweight were receiving dialysis treatment and infant age. Among transplanted recipients, a very short stature (OR: 1.64, 95% CI: 1.40-1.92) and glucocorticoid treatment (OR: 1.23, 95% CI: 1.03-1.47) were associated with a higher risk of being overweight/obese. BMI increased post-transplant, and a lower BMI and a higher age at the start of RRT were associated with greater BMI changes during RRT treatment.

CONCLUSIONS

Overweight and obesity, rather than underweight, are highly prevalent in European children on RRT. Short stature among graft recipients had a strong association with overweight, while underweight appears to be only a problem in infants. Our findings suggest that nutritional management in children receiving RRT should focus as much on the prevention and treatment of overweight as on preventing malnutrition.

Hepcidin in anemia of chronic kidney disease: review for the pediatric nephrologist

Anemia coincident with hyporesponsiveness to erythropoiesis-stimulating agents is an ongoing and prevalent problem in children with chronic kidney disease (CKD). The recently identified iron-regulatory protein hepcidin appears likely to play a significant role in this problem. Hepcidin up-regulation in the setting of CKD, with subsequent increased serum levels, results in impaired iron absorption from the intestine and decreased iron release from body storage sites. Ultimately, in the setting of such elevated levels, a state of functional iron deficiency may develop and lead to anemia due to iron-restricted erythropoiesis. Elevated hepcidin levels are expected in the face of decreased glomerular filtration rate and inflammation. Based on current evidence, it seems likely that hepcidin represents a potentially modifiable mediator of anemia of CKD and is thus a potential target for future anemia therapy. Currently, increased removal via intensified dialysis and-/or blockade of the inflammatory pathway appear to be two viable generic strategies for reducing hepcidin levels. Goals of directly manipulating the hepcidin pathway should offer the pediatric clinician new options for treating the complex anemia associated with CKD.

Anemia in children with chronic kidney disease

Anemia is a common comorbidity in children with chronic kidney disease (CKD). This condition is associated with multiple adverse clinical consequences and its management is a core component of nephrology care. Increased morbidity and mortality, increased risk of cardiovascular disease and decreased quality of life have been associated with anemia of CKD in children. Although numerous complex factors interact in the development of this anemia, erythropoietin deficiency and iron dysregulation (including iron deficiency and iron-restricted erythropoiesis) are the primary causes. In addition to iron supplementation, erythropoietin-stimulating agents (ESAs) can effectively treat this anemia, but there are important differences in ESA dose requirements between children and adults. Also, hyporesponsiveness to ESA therapy is a common problem in children with CKD. Although escalating ESA doses to target increased hemoglobin values in adults has been associated with adverse outcomes, no studies have demonstrated this association in children. The question of appropriate target hemoglobin levels in children, and the approach by which to achieve these levels, remains under debate. Randomized, controlled studies are needed to evaluate whether normalization of hemoglobin concentrations is beneficial to children, and whether this practice is associated with increased risks.

Association of chronic kidney disease with muscle deficits in children

The effect of chronic kidney disease (CKD) on muscle mass in children, independent of poor growth and delayed maturation, is not well understood. We sought to characterize whole body and regional lean mass (LM) and fat mass (FM) in children and adolescents with CKD and to identify correlates of LM deficits in CKD. We estimated LM and FM from dual energy x-ray absorptiometry scans in 143 children with CKD and 958 controls at two pediatric centers. We expressed whole body, trunk, and leg values of LM and FM as Z-scores relative to height, sitting height, and leg length, respectively, using the controls as the reference. We used multivariable regression models to compare Z-scores in CKD and controls, adjusted for age and maturation, and to identify correlates of LM Z-scores in CKD. Greater CKD severity associated with greater leg LM deficits. Compared with controls, leg LM Z-scores were similar in CKD stages 2 to 3 (difference: 0.02 [95% CI: -0.20, 0.24]; P = 0.8), but were lower in CKD stages 4 to 5 (-0.41 [-0.66, -0.15]; P = 0.002) and dialysis (-1.03 [-1.33, -0.74]; P < 0.0001). Among CKD participants, growth hormone therapy associated with greater leg LM Z-score (0.58 [0.03, 1.13]; P = 0.04), adjusted for CKD severity. Serum albumin, bicarbonate, and markers of inflammation did not associate with LM Z-scores. CKD associated with greater trunk LM and FM, variable whole body LM, and normal leg FM, compared with controls. In conclusion, advanced CKD associates with significant deficits in leg lean mass, indicating skeletal muscle wasting. These data call for prospective studies of interventions to improve muscle mass among children with CKD.

Cardiovascular disease in CKD in children: update on risk factors, risk assessment, and management

In young adults with onset of chronic kidney disease in childhood, cardiovascular disease is the most common cause of death. The likely reason for increased cardiovascular disease in these patients is a high prevalence of traditional and uremia-related cardiovascular disease risk factors during childhood chronic kidney disease. Early markers of cardiomyopathy, such as left ventricular hypertrophy and left ventricular dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, frequently are found in this patient population. The purpose of this review is to provide an update of recent advances in the understanding and management of cardiovascular disease risks in this population.

Current advances in chronic kidney disease in children: growth, cardiovascular, and neurocognitive risk factors

Linear growth and neurocognitive development are two of the most important differences between adults and children, in terms of clinical issues that must be addressed in patients with chronic kidney disease (CKD). Correction of metabolic acidosis, nutritional deficiency, and renal osteodystrophy improve linear growth, but many children require administration of growth hormone to achieve normal growth. A variety of neurocognitive deficits occur in children with CKD, although there has been an improvement in outcome via improved dialysis, correction of malnutrition, and decreased aluminum exposure. Although growth and neurocognitive development are delayed, cardiovascular complications are accelerated in children with CKD, and are reflected in a dramatic increase in cardiovascular mortality compared with healthy children. Other early cardiovascular complications in children with CKD include left ventricular hypertrophy, cardiac dysfunction, and vascular calcifications.

Assessment and Monitoring of Nutrition Status in Pediatric Peritoneal Dialysis Patients

Abnormalities of nutrition status are a common problem in children on peritoneal dialysis (PD) and a source of significant morbidity and mortality. The state of decreased body protein mass and fuel reserves (body protein and fat mass) common in PD patients is now better known as protein–energy wasting (PEW).

Protein–energy wasting is a slow, progressive process in chronic kidney disease. The correct approach to this problem includes measurement of early, intermediate, and late markers of PEW, and consideration of the risk factors specific to the patient and to PD.

The earliest markers of PEW are associated with some symptoms observed clinically: a decrease in dietary intake and an increase in inflammatory markers. The second stage in the development of PEW (patients with established PEW) is characterized by abnormalities in numerous markers: bioimpedance analysis (BIA) and anthropometric indices, other indices of body mass and composition, biochemical parameters, and indices of protein, glucose, and lipid metabolism. When PEW is established, clear clinical signs become evident: patients in this stage are characterized by high rates of hospitalization and an increased risk for morbidity and mortality as compared with patients without cachexia.

Risk factors for PEW can already be present in an apparently well-nourished child who initiates PD: glucose absorption from PD fluid, abdominal distension from PD volume, gastroesophageal reflux, and even more importantly, inadequate dialysis dose in relation to decline in residual renal function.

Given the complexity of the pathogenesis and clinical picture of PEW, no single measure, but rather panels of nutritional measures are necessary to diagnose the condition. Combined nutrition scores such as the anthropometry–BIA nutrition score may add value to the monitoring of nutrition status in children on PD.

Clinical outcome of children with chronic kidney disease in a pre-dialysis interdisciplinary program

The purpose of this retrospective cohort study was to describe the outcome of 107 patients with chronic kidney disease (CKD) admitted to a pre-dialysis interdisciplinary management program from 1990 to 2006. The events of interest were progression to CKD stage 5 (renal survival), patient survival, hypertension, and somatic growth. Survival was studied by the Kaplan-Meier method. Patients were classified into four groups according to their primary renal disease: congenital nephro-uropathies; glomerular diseases; cystic disease, and miscellaneous. Median follow-up time was 94 months [Interquartile (IQ) range 38-145]. The probability of reaching CKD stage 5 was estimated to be 36% by 5 years after admission. As a whole, the mean estimated glomerular filtration rate (GFR) decrease per year was 5.8 ml/min per 1.73 m(2) body surface area [standard deviation (SD) 12.4]. The glomerular diseases group showed a median rate of GFR deterioration of 10 ml/min per 1.73 m(2) per year (IQ range -24 to -5.7), whereas the median rate of GFR deterioration for the groups with cystic diseases, congenital nephro-uropathies, and miscellanea were 2.5 ml/min (IQ range -10 to +0.34), 2.2 ml/min (IQ range -5.0 to -0.52), and 0.36 ml/min (IQ range -2.5 to +2.6), respectively (P < 0.001). The results of this study support the view that children and adolescents with glomerular diseases present a faster deterioration of renal function. Therefore, patients with glomerular diseases need to be referred early to a pediatric nephrology center so that suboptimal pre-dialysis care might possibly be avoided.

Prevalence of malnutrition in pediatric hospital patients

PURPOSE OF REVIEW

Hospital protein-energy malnutrition and its adverse consequences were already described back in 1980. The purpose of this review is to describe the current prevalence of malnutrition in hospitalized children and to describe current risk groups.

RECENT FINDINGS

Different definitions have been used to describe malnutrition. According to WHO criteria, the SD score with a cutoff of less than -2 should be used to define malnutrition and to compare prevalence data. Using the SD score for weight for height or equivalent criteria, the prevalence of acute malnutrition over the last 10 years in hospitalized children in Germany, France, the UK and the USA varied between 6.1 and 14%, whereas in Turkey up to 32% of patients with malnutrition were reported. Acute malnutrition is still highly prevalent in children with an underlying disease; however, the prevalence rate seems lower in children with cystic fibrosis and malignancies.

SUMMARY

The prevalence of acute malnutrition of children admitted to hospital is still considerably high, but there is a scarcity of data concerning the nutritional status during hospital admission. Screening tools to identify children at risk of developing malnutrition might be helpful.

Disparate outcomes in pediatric peritoneal dialysis patients by gender/race in the End-Stage Renal Disease Clinical Performance Measures project

Associations between achievement of adult Kidney Disease Outcomes Quality Initiative (KDOQI) targets for hemoglobin, adequacy and albumin, and race and gender were determined for pediatric peritoneal dialysis patients from the End-Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) project for the period October 2004-March 2005. Fifty-six percent (427/761) of patients were male. Sixty-six percent (500/761) of patients were White. There were no differences in achievement of targets for adults by gender, and no differences in adequacy parameters by race. Blacks had lower mean hemoglobin levels than did Whites (11.1 +/- 1.6 g/dl vs 11.8 +/- 1.4 g/dl, P < 0.0001). Blacks were more likely to have mean hemoglobin levels < 10 g/dl (24% vs 11%, P < 0.0001) and less likely to achieve mean hemoglobin > 11 g/dl (56% vs 72%, P < 0.0001). Whites were more likely to achieve mean serum albumin levels > 4.0/3.7 g/dl [bromocresol green/bromocresol purple (BCG/BCP)] than Blacks were (35% vs 26%, P = 0.0376). In multivariate logistic regression models, White race was associated with mean hemoglobin levels > 11 g/dl [adjusted odds ratio (adj OR) 2.7, 95% confidence interval (CI) 1.7, 4.3] and mean serum albumin > 4.0/3.7 g/dl (BCG/BCP) (adj OR 1.9, 95% CI 1.3, 2.9]. Further study is needed of factors associated with anemia on peritoneal dialysis and barriers to its correction.

Applying Translational Research in Understanding Complications and Defining Targets for Intervention: Inflammation in PD as a Model

The bench-to-bedside approach to translational research is becoming increasingly important to efficiently advance understanding of the mechanisms underlying disease and to improve the quality of patient care. Although this investigation model has been practiced since the early days of the therapy, robust research platforms built to practice translational research have only recently been structured in the field of peritoneal dialysis. Experience with a translational research environment that generated most of the information cited in this overview is the core of this manuscript. The central investigation theme described is how to approach the cardiovascular complications of peritoneal dialysis. The research question was, could the continuous activation of inflammatory pathways be central in this process and represent a relevant target for interventions?