Physical activity and screen time in adolescents in the chronic kidney disease in children (CKiD) cohort

Physical (in)activity and screen-based media use of adolescents with juvenile idiopathic arthritis over time - data from a German inception cohort

BACKGROUND

Regular physical activity (PA) has been proven to help prevent non-communicable diseases and is beneficial for disease management in chronically ill populations. Physical inactivity and recreational screen-based media (SBM) use are related to poor health outcomes and common among youth. This study aimed to (1) investigate PA levels and recreational SBM use of adolescents with JIA over time and (2) compare these behaviours with those of their peers.

METHODS

Data from JIA patients and their peers enrolled in the inception cohort study ICON at 11 German centers were analyzed. Individuals aged 13 and over were followed prospectively with questionnaires concerning PA level, recreational SBM use, and health-related quality of life (HRQoL) at a two-year interval. Group by time interactions were analyzed using linear mixed models.

RESULTS

Data of 214 patients (mean age at first documentation 14.4 ± 0.9 years, female 63%) and 141 peers could be considered. At first documentation, patients were less physically active compared to their peers (p < 0.001). In contrast to their peers, patients' PA levels increased over time (OR 3.69; 95% CI: 1.01-13.50, p = 0.048). Mean screen time did not differ significantly between patients and peers (first documentation: 3.5 h vs. 3.0 h, p = 0.556; follow-up: 3.6 h vs. 3.3 h, p = 0. 969). During the observation period, male patients reported higher PA levels than female patients, but also higher screen time levels. While low socioeconomic status (SES) (OR 14.40; 95%-CI: 2.84-73.15) and higher cJADAS-10 score (OR 1.31; 95%-CI: 1.03-1.66) increased the likelihood for high SBM use (≥ 4.5 h/d), higher PedsQL psychosocial health score (OR 0.93; 95%-CI: 0.88-0.99) was associated with a decreased likelihood.

CONCLUSIONS

Adolescents with JIA become more physically active over the disease course and achieve comparable levels of PA and recreational screen time to their peers. However, the vast majority appear to be insufficiently physically active. Future interventions to promote healthy lifestyles should include gender and SES as important determinants to reach most vulnerable groups.

School attendance and sport participation amongst children with chronic kidney disease: a cross-sectional analysis from the Kids with CKD (KCAD) study

BACKGROUND

School attendance and life participation, particularly sport, is a high priority for children with chronic kidney disease (CKD). This study is aimed at assessing the association between CKD stage, sports participation, and school absences in children with CKD.

METHODS

Using data from the binational Kids with CKD study (ages 6-18 years, n = 377), we performed multivariable regression to evaluate the association between CKD stage, school absences, and sports participation.

RESULTS

Overall, 62% of participants played sport with the most frequent sport activities engaged in being swimming (17%) and soccer (17%). Compared to children with CKD 1-2, the incidence rate ratios (IRR) (95% CI) for sports participation amongst children with CKD 3-5, dialysis, or transplant were 0.84 (0.64-1.09), 0.59 (0.39-0.90), and 0.75 (0.58-0.96), respectively. The median (IQR) days of school absences within a four-week period were 1 day (0-1), with children on dialysis reporting the highest number of school absences (9 days (5-15)), followed by transplant recipients (2 days (1-7)), children with CKD 3-5 (1 day (0-3)), and with CKD 1-2 (1 day (0-3)). Duration of CKD modified the association between CKD stage and school absences, with children with a transplant experiencing a higher number of missed school days with increasing duration of CKD, but not in children with CKD 1-5 or on dialysis (p-interaction < 0.01).

CONCLUSIONS

Children receiving dialysis and with a kidney transplant had greater school absences and played fewer sports compared to children with CKD stages 1-2. Innovative strategies to improve school attendance and sport participation are needed to improve life participation of children with CKD.

Associations of body mass index (BMI) and BMI change with progression of chronic kidney disease in children

BACKGROUND

Obesity is prevalent among children with chronic kidney disease (CKD) and is associated with cardiovascular disease and reduced quality of life. Its relationship with pediatric CKD progression has not been described.

METHODS

We evaluated relationships between both body mass index (BMI) category (normal, overweight, obese) and BMI z-score (BMIz) change on CKD progression among participants of the Chronic Kidney Disease in Children study. Kaplan-Meier survival curves and multivariable parametric failure time models depict the association of baseline BMI category on time to kidney replacement therapy (KRT). Additionally, the annualized percentage change in estimated glomerular filtration rate (eGFR) was modeled against concurrent change in BMIz using multivariable linear regression with generalized estimating equations which allowed for quantification of the effect of BMIz change on annualized eGFR change.

RESULTS

Participants had median age of 10.9 years [IQR: 6.5, 14.6], median eGFR of 50 ml/1.73 m2 [IQR: 37, 64] and 63% were male. 160 (27%) of 600 children with non-glomerular and 77 (31%) of 247 children with glomerular CKD progressed to KRT over a median of 5 years [IQR: 2, 8]. Times to KRT were not significantly associated with baseline BMI category. Children with non-glomerular CKD who were obese experienced significant improvement in eGFR (+ 0.62%; 95% CI: + 0.17%, + 1.08%) for every 0.1 standard deviation concurrent decrease in BMI. In participants with glomerular CKD who were obese, BMIz change was not significantly associated with annualized eGFR change.

CONCLUSION

Obesity may represent a target of intervention to improve kidney function in children with non-glomerular CKD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Malnutrition Patterns in Children with Chronic Kidney Disease

Malnutrition is frequent in children with chronic kidney disease (CKD). Apart from undernutrition and protein energy wasting (PEW), overnutrition prevalence is rising, resulting in fat mass accumulation. Sedentary behavior and unbalanced diet are the most important causal factors. Both underweight and obesity are linked to adverse outcomes regarding renal function, cardiometabolic risk and mortality rate. Muscle wasting is the cornerstone finding of PEW, preceding fat loss and may lead to fatigue, musculoskeletal decline and frailty. In addition, clinical data emphasize the growing occurrence of muscle mass and strength deficits in patients with fat mass accumulation, attributed to CKD-related wasting processes, reduced physical activity and possibly to obesity-induced inflammatory diseases, leading to sarcopenic obesity. Moreover, children with CKD are susceptible to abdominal obesity, resulting from high body fat distribution into the visceral abdomen compartment. Both sarcopenic and abdominal obesity are associated with increased cardiometabolic risk. This review analyzes the pathogenetic mechanisms, current trends and outcomes of malnutrition patterns in pediatric CKD. Moreover, it underlines the importance of body composition assessment for the nutritional evaluation and summarizes the advantages and limitations of the currently available techniques. Furthermore, it highlights the benefits of growth hormone therapy and physical activity on malnutrition management.

Physical activity and the 'pediatric inactivity triad' in children living with chronic kidney disease: a narrative review

The ‘paediatric inactivity triad’ (PIT) framework consists of three complex inter-related conditions that influence physical inactivity and related health risks. In those living with chronic kidney disease (CKD), a multi-factorial milieu of components likely confound the PIT elements, resulting in a cycle of decreased physical functioning and reduced physical activity. In this review, we explore and summarize previous research on each of the three principal PIT components (exercise deficit disorder, dynapenia, and physical illiteracy) in the pediatric CKD population. We found those living with CKD are significantly physically inactive compared to their peers. Physical inactivity occurs early in the disease process and progressively gets worse as disease burden increases. Although physical activity appears to increase post-transplantation, it remains lower compared to healthy controls. There is limited evidence on interventions to increase physical activity behaviour in this population, and those that have attempted have had negligible effects. Studies reported profound reductions in muscle strength, physical performance, and cardiorespiratory fitness. A small number of exercise-based interventions have shown favourable improvements in physical function and cardiorespiratory fitness, although small sample sizes and methodological issues preclude the generalization of findings. Physical activity must be adapted and individualized to the needs and goals of the children, particularly those with acute and chronic medical needs as is the case in CKD, and further work is needed to define optimal interventions across the life course in this population if we aim to prevent physical activity declining further.

Interaction of Hydration Status and Physical Activity Level on Early Renal Damage in Children: A Longitudinal Study

BACKGROUND

Optimal water intake positively affects various aspects of human physiology, especially renal function. Physical activity (PA) may have an impact on hydration status and renal health, but the interaction of hydration status and PA level on renal function is not well-studied in children.

METHODS

We conducted four waves of urine assays in our child cohort (PROC) study from October 2018 to November 2019 in Beijing, China. We measured urinary specific gravity, β2-microglobulin (β2-MG), and microalbumin (MA) excretion to assess hydration status and renal damage in the context of PA level and other covariates among 1,914 primary school children. We determined the associations of renal damage with the interaction of hydration status and PA level using generalized linear mixed-effects models.

RESULTS

The prevalence of dehydration was 35.0%, 62.1%, 63.9%, and 63.3%, and the prevalence of insufficient PA was 86.2%, 44.9%, 90.4%, and 90.2% from wave 1 to wave 4 among 1,914 primary school children. From wave 1 to wave 4, the prevalence of renal tubular damage had a significant increasing trend of 8.8%, 15.9%, 25.7%, and 29.0% (Z = 16.9, P < 0.001), while the prevalence of glomerular damage revealed a declining trend of 5.6%, 5.5%, 4.4%, and 4.1% (Z = -2.4, P = 0.016). There were stable longitudinal associations of renal tubular and glomerular damage with hydration status (euhydration: OR = 0.50 and 0.33, respectively) but not with PA level. In multivariate analysis, significant interactions of hydration status and PA level were noted with renal tubular damage (β = 0.43, P = 0.014) and glomerular damage (β = 0.60, P = 0.047). Children with euhydration and insufficient PA were less likely to have renal tubular damage (OR = 0.46, 95% CI: 0.39, 0.53) or glomerular damage (OR = 0.28, 95% CI: 0.20, 0.39); children with euhydration and sufficient PA were also less likely to have renal tubular damage (OR = 0.57, 95% CI: 0.44, 0.75) or glomerular damage (OR = 0.47, 95% CI: 0.30, 0.74), adjusting for age, sex, BMI z-score, standardized SBP, sleep duration, computer/cell phone screen time, and fruit and vegetable intake.

CONCLUSION

Children with euhydration and either sufficient or insufficient PA were less likely to have early renal damage. Adequate daily water intake for children is important, especially after PA.

Managing the Nutritional Requirements of the Pediatric End-Stage Kidney Disease Graduate

The pediatric patient with end-stage kidney disease who transitions to the adult dialysis unit or nephrology center requires a unique nutritional focus. Clinicians in the adult center may be faced with complex issues that have often been part of the patient's journey since early childhood. The causes of kidney disease in children are often quite different than those which affect the adult population and may require different nutritional priorities. Abnormal growth including severe short stature, underweight, overweight or obesity, and poor musculature may affect the long-term health and psychosocial well-being of these patients. Nutritional assessment of these patients should include a focus on past growth and anthropometric data, dietary information, including appetite, quality of diet, and assessment of biochemical data through a pediatric lens. This review discusses the unique factors that must be considered when transitioning pediatric patients and notes major recommendations from a compilation of pediatric guideline statements.

Relation of Anxiety, Depression, and Behavioral Problems With Time Allocated to Television, Computer, and Smartphone in Children Receiving Renal Replacement Therapy

OBJECTIVES

Children and adolescents with chronic diseases have more screen exposure time compared with their healthy peers. In this study, we investigated screen exposure time of children who received renal replacement therapy, which included kidney transplant and dialysis treatment, versus a healthy control group.

MATERIALS AND METHODS

Our study included 55 children and adolescents between the ages of 8 and 18 years. Although 28 participants did not have any chronic disease, 27 had chronic diseases and received renal replacement therapy. Among these patients, 17 had kidney transplant and 10 were receiving dialysis. A sociodemographic information form and the Conners Short-Form Parent Rating Scale were given to parents. Pediatric and adolescent patients completed the Children's Depression Inventory and Spielberger State-Trait Anxiety Scale-2. We analyzed differences between the groups with and without renal replacement therapy and examined relations between continuous variables.

RESULTS

Duration of television screen time was significantly higher in children and adolescents receiving renal replacement therapy. Patients in the renal replacement therapy group showed a positive correlation between the Conners Short-Form Parent Rating Scale anxiety subscores and duration of smartphone use. In the kidney transplant recipient group, smartphone and computer durations were positively correlated and television duration was negatively correlated with the Conners Short-Form Parent Rating Scale behavioral problems subscores.

CONCLUSIONS

Children on renal replacement therapy may be at risk in terms of excessive television exposure. Children who are on dialysis and have had a kidney transplant may be more prone to the negative effects of screen exposure than healthy peers who do not have chronic illnesses. These children and adolescents should be closely monitored to avoid the negative effects of excessive screen exposure.

Assessment and management of obesity and metabolic syndrome in children with CKD stages 2-5 on dialysis and after kidney transplantation-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

Obesity and metabolic syndrome (O&MS) due to the worldwide obesity epidemic affects children at all stages of chronic kidney disease (CKD) including dialysis and after kidney transplantation. The presence of O&MS in the pediatric CKD population may augment the already increased cardiovascular risk and contribute to the loss of kidney function. The Pediatric Renal Nutrition Taskforce (PRNT) is an international team of pediatric renal dietitians and pediatric nephrologists who develop clinical practice recommendations (CPRs) for the nutritional management of children with kidney diseases. We present CPRs for the assessment and management of O&MS in children with CKD stages 2-5, on dialysis and after kidney transplantation. We address the risk factors and diagnostic criteria for O&MS and discuss their management focusing on non-pharmacological treatment management, including diet, physical activity, and behavior modification in the context of age and CKD stage. The statements have been graded using the American Academy of Pediatrics grading matrix. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs based on the clinical judgment of the treating physician and dietitian. Research recommendations are provided. The CPRs will be periodically audited and updated by the PRNT.

Longitudinal Follow-Up on Cardiopulmonary Exercise Capacity Related to Cardio-Metabolic Risk Factors in Children With Renal Transplants

Background: Children with chronic kidney disease, including those treated with kidney transplantation (KT), have an increased risk of cardiovascular disease. The aim of this study was to examine the cardiopulmonary exercise capacity after KT compared to matched controls, to relate the results to physical activity, blood pressure and biochemical findings and to follow exercise capacity over time.

Methods: Patients with KT (n = 38, age 7.7–18 years), with a mean time from transplantation of 3.7 years (0.9–13.0) and mean time in dialysis 0.8 years, were examined at inclusion and annually for up to three years. Healthy controls (n = 17, age 7.3–18.6 years) were examined once. All subjects underwent a cardiopulmonary exercise test, resting blood pressure measurement, anthropometry and activity assessment. Patients also underwent echocardiography, dual-energy X-ray absorptiometry (DXA), 24-h ambulatory BP measurements (ABPM), assessment of glomerular filtration rate (GFR) and blood sampling annually.

Results: As compared to healthy controls, KT patients showed decreased exercise capacity measured both as VO_2peak (34.5 vs. 43.9 ml/kg/min, p < 0.001) and maximal load (2.6 vs. 3.5 W/kg, p < 0.0001), similarly as when results were converted to z-scores. No significant difference was found in weight, but the KT patients were shorter and had higher BMI z-score than controls, as well as increased resting SBP and DBP z-scores. The patient or parent reported physical activity was significantly lower in the KT group compared to controls (p < 0.001) In the combined group, the major determinants for exercise capacity z-scores were activity score and BMI z-score (β = 0.79, p < 0.0001 and β = −0.38, p = 0.007, respectively). Within the KT group, low exercise capacity was associated with high fat mass index (FMI), low activity score, low GFR and high blood lipids. In the multivariate analysis FMI and low GFR remained predictors of low exercise capacity. The longitudinal data for the KT patients showed no change in exercise capacity z-scores over time.

Conclusion: Patients with KT showed decreased exercise capacity and increased BP as compared to healthy controls. Exercise capacity was associated to GFR, physical activity, FMI and blood lipids. It did not improve during follow-up.

Longitudinal outcomes of body mass index in overweight and obese children with chronic kidney disease

BACKGROUND

Longitudinal changes in body mass index (BMI) among overweight and obese children with chronic kidney disease (CKD) are not well characterized. We studied longitudinal trajectories and correlates of these trajectories, as results may identify opportunities to optimize health outcomes.

METHODS

Longitudinal changes in age-sex-specific BMI z-scores over 1851 person-years of follow-up were assessed in 524 participants of the Chronic Kidney Disease in Children Study. A total of 353 participants were categorized as normal (BMI > 5th to < 85th percentile), 56 overweight (BMI ≥ 85th to 95th percentile) and 115 obese (BMI ≥ 95th percentile) based on the average of three BMI measurements during the first year of follow-up. Studied covariates included age, sex, race, CKD etiology, corticosteroid usage, household income, and maternal education.

RESULTS

In unadjusted analysis, BMI z-scores decreased over time in elevated BMI groups (overweight: mean = - 0.06 standard deviations (SD) per year, 95% CI: - 0.11, - 0.01; obese: mean = - 0.04 SD per year, 95% CI: - 0.07, - 0.01). Among obese children, only age was associated with change in BMI z-score; children < 6 years had a mean decrease of 0.19 SD during follow-up (95% CI: - 0.30, - 0.09). Socioeconomic factors were not associated with change in BMI.

CONCLUSION

Overweight and obese children with CKD demonstrated a significant annual decline in BMI, though the absolute change was modest. Among obese children, only age < 6 years was associated with significant decline in BMI. Persistence of elevated BMI in older children and adolescents with CKD underscores the need for early prevention and effective intervention.

Assessment of nutritional status in children with kidney diseases-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

In children with kidney diseases, an assessment of the child's growth and nutritional status is important to guide the dietary prescription. No single metric can comprehensively describe the nutrition status; therefore, a series of indices and tools are required for evaluation. The Pediatric Renal Nutrition Taskforce (PRNT) is an international team of pediatric renal dietitians and pediatric nephrologists who develop clinical practice recommendations (CPRs) for the nutritional management of children with kidney diseases. Herein, we present CPRs for nutritional assessment, including measurement of anthropometric and biochemical parameters and evaluation of dietary intake. The statements have been graded using the American Academy of Pediatrics grading matrix. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs based on the clinical judgment of the treating physician and dietitian. Audit and research recommendations are provided. The CPRs will be periodically audited and updated by the PRNT.

Cardiovascular disease in childhood and adolescence: Lessons from children with chronic kidney disease

Children suffering from chronic kidney disease (CKD) have the apparent highest risk for the development of cardiovascular disease (CVD) at a young age. While symptoms of CVD are characteristically absent in childhood and adolescence, remodelling of the myocardium, medium and large-sized arteries and of the microcirculation is clinically significant and can be assessed with non-invasive technology. Kidney disease and its progression are the driver of CVD, mediated by an unparalleled accumulation of risk factors converging on several comorbid conditions including hypertension, anaemia, dyslipidaemia, disturbed mineral metabolism and chronic persistent inflammation. Large prospective paediatric cohorts studies have provided valuable insights into the pathogenesis and the progression of CKD-induced cardiovascular comorbidity and have characterised the cardiovascular phenotype in young patients. They have also provided the rationale for close monitoring of risk factors and have defined therapeutic targets. Recently discovered new biomarkers could help identify the individual risk for CVD. Prevention of CVD by aggressive therapy of modifiable risk factors is essential to enable long-term survival of young patients with CKD.

Grip strength in children with chronic kidney disease

BACKGROUND

The relationship between muscle strength and chronic kidney disease (CKD) in children is unknown. This study aims to quantify the association between grip strength (GS) and kidney function and to explore factors associated with grip strength in children and adolescents with CKD.

METHODS

We included 411 children (699 GS assessments) of the Chronic Kidney Disease in Children (CKiD) study. They were matched by age, sex, and height to a healthy control from the National Health and Nutrition Examination Survey to quantify the relationship between GS and CKD. Linear mixed models were used to identify factors associated with GS among CKD patients.

RESULTS

Median GS z-score was - 0.72 (IQR - 1.39, 0.11) among CKD patients with CKD stages 2 through 5 having significantly lower GS than CKD stage 1. Compared with healthy controls, CKiD participants had a decreased GS z-score (- 0.53 SD lower, 95% CI - 0.67 to - 0.39) independent of race/ethnicity and body mass index. Factors associated with reduced GS included longer duration of CKD, pre-pubertal status, delayed puberty, neuropsychiatric comorbidities, need of feeding support, need for alkali therapy, and hemoglobin level. Decreased GS was also associated with both a lower frequency and intensity of physical activity.

CONCLUSIONS

CKD is associated with impaired muscle strength in children independent of growth retardation and BMI. Exposure to CKD for a prolonged time is associated with impaired muscle strength. Potential mediators of the impact of CKD on muscle strength include growth retardation, acidosis, poor nutritional status, and low physical activity. Additional studies are needed to assess the efficacy of interventions targeted at these risk factors.

The Impact of Home-Based Exercise Program on Physical Function of Chronic Kidney Disease Patients: A Meta-Analysis of Randomized Controlled Trials

Background Home-based exercise program showed the potential in improving physical function of chronic kidney disease patients, and it might need low associated costs. We conducted a systematic review and meta-analysis to explore the impact of home-based exercise program on physical function of chronic kidney disease patients.

Methods PubMed, EMBASE, Web of science, EBSCO, and Cochrane library databases were systematically searched. This meta-analysis included randomized controlled trials (RCTs) assessing the effect of home-based exercise program on physical function of chronic kidney disease patients. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcomes were 6-min walk test and grip strength change.

Results Seven RCTs were included in the meta-analysis. Overall, compared with control intervention in chronic kidney disease patients, home-based exercise program could significantly improve 6-min walk test (MD=79.01; 95% CI=22.39–135.62; P=0.006) and grip strength (SMD=0.52; 95% CI=0.14–0.89; P=0.007), but showed no impact on pain scores (SMD=−1.43; 95% CI=−3.75 to 0.88; P=0.22), Kidney Disease Quality of life including symptom/problem list (SMD=1.92; 95% CI=−1.06 to 4.90; P=0.21), effects of kidney disease (SMD=−3.69; 95% CI=−8.56 to 1.19; P=0.14), or burden of kidney disease (SMD=1.04; 95% CI=−0.75 to 2.82; P=0.26).

Conclusions Home-based exercise program might improve physical function for chronic kidney disease, and more RCTs should be conducted to confirm this issue.

Bone Health in Glomerular Kidney Disease

PURPOSE OF REVIEW

To summarize the literature regarding alterations in bone health in patients with glomerular kidney disease and highlight areas in need of additional investigation.

RECENT FINDINGS

There is mounting evidence that children and adults with glomerular conditions, with or without compromised kidney function, comprise a distinct subgroup of patients with unique risk factors for altered bone health. Patients with glomerular kidney disease are exposed to both disease-related and treatment-related factors that affect bone structure and function. In addition to chronic kidney disease-related risk factors for impaired bone health, high rates of exposure to osteotoxic medications, varying degrees of systemic inflammation, and altered vitamin D metabolism may contribute to compromised bone health in individuals with glomerular disease. Further study is needed to better understand these risk factors and the complex interaction between the immune system and bone cells in glomerular disease.

Change in Dyslipidemia with Declining Glomerular Filtration Rate and Increasing Proteinuria in Children with CKD

BACKGROUND AND OBJECTIVES

Dyslipidemia, a risk factor for cardiovascular disease, is common in CKD but its change over time and how that change is influenced by concurrent progression of CKD have not been previously described.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In the CKD in Children study we prospectively followed children with progressive CKD and utilized multivariable, linear mixed-effects models to quantify the longitudinal relationship between within-subject changes in lipid measures (HDL cholesterol, non-HDL cholesterol, triglycerides) and within-subject changes in GFR, proteinuria, and body mass index (BMI).

RESULTS

A total of 508 children (76% nonglomerular CKD, 24% glomerular CKD) had 2-6 lipid measurements each, with a median follow-up time of 4 (interquartile range [IQR], 2.1-6.0) years. Among children with nonglomerular CKD, dyslipidemia was common at baseline (35%) and increased significantly as children aged; 43% of children with glomerular CKD had dyslipidemia at baseline and demonstrated persistent levels as they aged. Longitudinal increases in proteinuria were independently associated with significant concomitant increases in non-HDL cholesterol (nonglomerular: 4.9 [IQR, 3.4-6.4] mg/dl; glomerular: 8.5 [IQR, 6.0-11.1] mg/dl) and triglycerides (nonglomerular: 3% [IQR, 0.8%-6%]; glomerular: 5% [IQR, 0.6%-9%]). Decreases in GFR over follow-up were significantly associated with concomitant decreases of HDL cholesterol in children with nonglomerular CKD (-1.2 mg/dl; IQR, -2.1 to -0.4 mg/dl) and increases of non-HDL cholesterol in children with glomerular CKD (3.9 mg/dl; IQR, 1.4-6.5 mg/dl). The effects of increased BMI also affected multiple lipid changes over time. Collectively, glomerular CKD displayed stronger, deleterious associations between within-subject change in non-HDL cholesterol (9 mg/dl versus 1.2 mg/dl; P<0.001) and triglycerides (14% versus 3%; P=0.004), and within-subject change in BMI; similar but quantitatively smaller differences between the two types of CKD were noted for associations of within-subject change in lipids to within-subject change in GFR and proteinuria.

CONCLUSIONS

Dyslipidemia is a common and persistent complication in children with CKD and it worsens in proportion to declining GFR, worsening proteinuria, and increasing BMI.

Cachexia/Protein energy wasting syndrome in CKD: Causation and treatment

Cachexia is a multifactorial syndrome defined by significant body weight loss, fat and muscle mass reduction, and increased protein catabolism. Protein energy wasting (PEW) is characterized as a syndrome of adverse changes in nutrition and body composition being highly prevalent in patients with CKD, especially in those undergoing dialysis, and it is associated with high morbidity and mortality in this population. Multiple mechanisms are involved in the genesis of these adverse nutritional changes in CKD patients. There is no obvious distinction between PEW and cachexia from a pathophysiologic standpoint and should be considered as part of the spectrum of the same nutritional disorder in CKD with similar management approaches for prevention and treatment based on current understanding. A plethora of factors can affect the nutritional status of CKD patients requiring a combination of therapeutic approaches to prevent or reverse protein and energy depletion. At present, there is no effective pharmacologic intervention that prevents or attenuates muscle atrophy in catabolic conditions like CKD. Prevention and treatment of uremic muscle wasting involve optimal nutritional support, correction of acidosis, and physical exercise. There has been emerging consistent evidence that active treatment, perhaps by combining nutritional interventions and resistance exercise, may be able to improve but not totally reverse or prevent the supervening muscle wasting and weakness. Active research into more direct pharmacological treatment based on basic mechanistic research is much needed for this unmet medical need in patients with CKD.

Cardiovascular Disease in Children and Adolescents With Chronic Kidney Disease

The lifespan of children with advanced chronic kidney disease (CKD), although improved over the past 2 decades, remains low compared with the general pediatric population. Similar to adults with CKD, cardiovascular disease accounts for a majority of deaths in children with CKD because these patients have a high prevalence of traditional and uremia-related risk factors for cardiovascular disease. The cardiovascular alterations that cause these terminal events begin early in pediatric CKD. Initially, these act to maintain hemodynamic homeostasis. However, as the disease progresses, these modifications are unable to sustain cardiovascular function in the long term, leading to left ventricular failure, depressed cardiorespiratory fitness, and sudden death. In this review, we discuss the prevalence of the risk factors associated with cardiovascular disease in pediatric patients with CKD, the pathophysiology that stimulates these changes, the cardiac and vascular adaptations that occur in these patients, and management of the cardiovascular risk in these patients.

Muscle wasting in chronic kidney disease

Loss of lean body mass is a relevant component of the cachexia, or protein energy wasting (PEW), syndrome. Reduced muscle mass seems to be the most solid criterion for the presence of cachexia/PEW in patients with chronic kidney disease (CKD), and those with greater muscle mass loss have a higher risk of death. Children with CKD have many risk factors for lean mass and muscle wasting, including poor appetite, inflammation, growth hormone resistance, and metabolic acidosis. Mortality risks in patients with CKD increases as body mass index (BMI) and weight decreases. However, data regarding cachexia/PEW and muscle wasting in children with CKD is scarce due to lack of consensus in diagnostic criteria and an appropriate investigative methodology. Further research is urgently needed to address this important complication in the pediatric CKD setting, which may have fundamental impact on clinical outcomes.

Skeletal manifestations of renal disease in childhood

PURPOSE OF REVIEW

This review summarizes recent findings on musculoskeletal health in three chronic renal conditions of childhood: chronic kidney disease stages 2-5D, nephrotic syndrome, and urolithiasis. Findings with important clinical implications warranting further investigation are highlighted.

RECENT FINDINGS

Recent cohort studies have demonstrated a high burden of fracture and progressive deficits of cortical bone in children with chronic kidney disease. Lower cortical density is associated with incident fracture and may be an important therapeutic target. Parathyroid hormone and calcium are independent correlates of cortical density, and modifiable factors for fracture include parathyroid hormone and phosphate binder use. Children with nephrotic syndrome, even with normal renal function, have evidence of abnormal bone metabolism and structure, and vitamin D deficiency may be an important modifiable risk factor in this population. Urolithiasis has been associated with reduced bone mineral density and is increasingly common in children and adolescents. Population-based data found a significantly increased risk of fracture in adolescent males and young women.

SUMMARY

Recent findings substantiate concern regarding the particular vulnerability of the growing skeleton to chronic renal disease. Studies are needed to determine how to optimize assessment and management of bone health in children with these conditions, particularly in terms of calcium and vitamin D requirements, with the goal of improving childhood bone accrual for lifelong fracture prevention.

Relationships of Measured Iohexol GFR and Estimated GFR With CKD-Related Biomarkers in Children and Adolescents

BACKGROUND

2 valid and reliable estimated glomerular filtration rate (GFR) equations for the pediatric population have been developed from directly measured GFR data in the Chronic Kidney Disease in Children (CKiD) cohort: the full CKiD and bedside CKiD equations. Although adult GFR estimating equations replicate relationships of measured GFR with biomarkers, it is unclear whether similar patterns exist among children and adolescents with chronic kidney disease (CKD).

STUDY DESIGN

Prospective cohort study in children and adolescents.

SETTINGS & PARTICIPANTS

730 participants contributed 1,539 study visits.

PREDICTORS

Measured GFR by plasma iohexol disappearance (mGFR), estimated GFR by the full CKiD equation (eGFR_CKiDfull; based on serum creatinine, cystatin C, serum urea nitrogen, height, and sex), and estimated GFR by the bedside CKiD equation (eGFR_CKiDbed; calculated as 41.3 × height [m]/serum creatinine [mg/dL]) were predictors of CKD-related biomarkers. Deviations of mGFR from eGFR_CKiDfull and deviations of eGFR_CKiDfull from eGFR_CKiDbed from linear regressions (ie, residuals) were included in bivariate analyses.

OUTCOMES & MEASUREMENTS

CKD-related biomarkers included values for urine protein-creatinine ratio, blood hemoglobin, serum phosphate, bicarbonate, potassium, systolic and diastolic blood pressure z scores, and height z scores.

RESULTS

The median age of 730 participants with CKD was 12.5 years, with median mGFR, eGFR_CKiDfull, and eGFR_CKiDbed of 51.8, 54.0, and 53.2mL/min/1.73m², respectively. eGFR_CKiDfull demonstrated as strong or stronger associations with CKD-related biomarkers than mGFR; eGFR_CKiDbed associations were significantly attenuated (ie, closer to the null). Residual information in mGFR did not substantially increase explained variability. eGFR_CKiDbed estimated faster GFR decline relative to mGFR and eGFR_CKiDfull.

LIMITATIONS

Simple linear summaries of biomarkers may not capture nonlinear associations.

CONCLUSIONS

eGFR_CKiDfull closely approximated mGFR to describe relationships with CKD-severity indicators and progression in this pediatric CKD population. eGFR_CKiDbed offered similar inferences, but associations were attenuated and rate of progression was overestimated. The eGFR_CKiDfull equation from 2012 is preferred for pediatric research purposes.

Assessment of dietary intake of children with chronic kidney disease

OBJECTIVE

Our aim was to characterize the nutrient intake of children with chronic kidney disease (CKD) relative to recommended intake levels.

METHODS

We conducted a cross-sectional study of dietary intake assessed by Food Frequency Questionnaire (FFQ) in The North American Chronic Kidney Disease in Children (CKiD) prospective cohort study. Nutrient intake was analyzed to estimate the daily consumption levels of various nutrients and compared with national guidelines for intake.

RESULTS

There were 658 FFQs available for analysis; 69.9 % of respondents were boys, with a median age [Interquartile range (IQR)] of 11 years (8-15). Median daily sodium, potassium, and phosphorus intake was 3089 mg (2294-4243), 2384 mg (1804-3076), and 1206 mg (894-1612) respectively. Sodium and phosphorus consumptions were higher than recommended in all age groups. Caloric intake decreased with dropping glomerular filtration rate (GFR) (p = 0.003). The median daily caloric intakes were 1307 kcal in male children 2-3 years old, 1875 kcal in children 4-8 years old, 1923 kcal in those 9-13 years old, and 2427 kcal in those 14-18 years old. Respective levels for girls were 1467 kcal, 1736 kcal, 1803 kcal, and 2281 kcal. Median protein intake exceeded recommended levels in all age groups, particularly among younger participants. Younger children were more likely than older children to exceed the recommended intakes for phosphorus (p < 0.001) and the age-specific recommended caloric intake (p < 0.001). Macronutrient distribution (carbohydrate:fat:protein) was consistent with recommendation.

CONCLUSIONS

Children in the CKiD cohort consumed more sodium, phosphorus, protein, and calories than recommended. The gap between actual consumption and recommendations indicates a need for improved nutritional counseling and monitoring.