Prevalence of complications in children with chronic kidney disease according to KDOQI

Zinc Supplementation Trial in Pediatric Chronic Kidney Disease: Effects on Circulating FGF-23 and Klotho

Background

Zinc status, its role in bone metabolism and efficacy of deficiency correction has not been well studied in children with chronic kidney disease (CKD).

Objectives

The primary objective was to investigate whether 3 months of oral zinc supplementation corrects zinc deficiency in children with CKD who have native or transplanted kidneys. The secondary objective was to compare circulating intact FGF-23 (iFGF-23), c-terminal FGF-23 (cFGF-23), and Klotho between zinc-sufficient and zinc-deficient children with CKD and to assess the relationship between circulating zinc, iFGF-23, cFGF-23, Klotho, bone biomarkers, copper, and phosphate excretion pre-supplementation and post-supplementation of zinc.

Methods

Forty-one children (25 male and 16 female, age 12.94 ± 4.13 years) with CKD in native or transplanted kidneys were recruited through 2 pediatric nephrology divisions in Ontario, Canada. Of those, 14 patients (9 native CKD, 5 transplant CKD) with identified zinc deficiency (64% enrollment rate) received zinc citrate supplement for 3 months: 10 mg orally once (4-8 years) or twice (9-18 years) daily.

Results

Zinc deficiency (plasma concentration < 11.5 µmol/L) was found in 22 patients (53.7%). A linear regression model suggested that zinc concentration reduced by 0.026 µmol/L (P = .04) for every 1-unit of estimated glomerular filtration rate (eGFR) drop. Zinc deficiency status was associated with higher serum iFGF-23; however, this was predominantly determined by the falling GFR. Zinc deficient and sufficient children had similar circulating c-FGF-23 and alpha-Klotho. Normalization of plasma zinc concentration was achieved in 8 (5 native CKD and 3 transplant CKD) out of 14 treated patients rising from 10.04 ± 1.42 to 12.29 ± 3.77 μmol/L (P = .0038). There were no significant changes in other biochemical measures in all treated patients. A statistically significant (P = .0078) rise in c-FGF-23 was observed only in a subgroup of 11 children treated with zinc but not receiving calcitriol.

Conclusions

Zinc status is related to kidney function and possibly connected to bone metabolism in patients with CKD. However, it plays a minor role in fine-tuning various metabolic processes. In this exploratory non-randomized study, 3 months supplementation with zinc corrected deficiency in just over half of patients and only modestly affected bone metabolism in asymptomatic CKD patients.

Assessment of the hematological profile of children with chronic kidney disease on follow-up at St. Paul's Hospital Millennium Medical College and Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia

BACKGROUND

Chronic kidney disease (CKD) is a major public health issue with an increasing incidence and prevalence worldwide. In CKD, hematological parameters are influenced, and the effect increases with CKD stage. Thus, the aim of this study was to assess hematological profile of children with CKD on follow up at Tikur Anbessa Specialized Hospital and St. Paul's Hospital Millennium Medical College in Addis Ababa, Ethiopia.

METHODS

A cross-sectional study was carried out from March 1 to June 30, 2021 among 238 children with CKD. EDTA tubes were used to collect 4 ml blood samples, which were then examined by Beckman Coulter automated hematology analyzer. SPSS Version 20 was used for statistical analysis, and a bivariate and multivariate regression model were applied to assess correlations. Mean and standard deviation was used to determine hematological profiles.

RESULTS

The total number of patients in the study were 238, with 42 (59.7%) of them being men. The majority of the patients (81%) had CKD stage 1. Mean ± standard deviation determined for white blood cell (WBC) parameters in (thousand/µL); WBC, Neutrophil, Lymphocytes, Eosinophil, Monocytes and Basophil were 8.93 ± 3.32, 4.6 ± 8.31, 2.79 ± 1.62, 0.31 ± 0.51, 0.50 ± 3.03 and 0.03 ± 0.24, respectively. For some of red blood cell (RBC) parameters; RBC (million/ µL), Hemoglobin (Hgb) (g/dL), Hematocrit (Hct) (%) and Mean cell volume (fl.) were 4.73 ± 0.87, 12.82 ± 2.76, 38.28 ± 7.53 and 80.32 ± 7.89, respectively. For the platelet count (PLT) (thousand/µL) and Mean Platelet volume (MPV) (fL) 349.34 ± 130.18 and 9.03 ± 4.31 were determined, respectively. This study also found hematologic parameters such as RBC, HGB, HCT and MPV were found to be positively correlated with eGFR with a P-value < 0.05 for all parameters.

CONCLUSION

The study found that the majority of study participants were in stages 1 to 3 based on their estimated glomerular filtration rate (eGFR). Some of hematological parameters found to have positive correlation with eGFR. There is a need to improve multiple aspects of CKD management, including routine hematological tests for children with chronic kidney disease.

Identifying barriers and utility of obtaining ambulatory blood pressure monitoring in a pediatric chronic kidney disease population

BACKGROUND

Hypertension is a prevalent complication of Chronic Kidney Disease (CKD) and Ambulatory Blood Pressure Monitoring (ABPM) is the gold standard for diagnosis. The aim of our study was to assess the usefulness of obtaining ABPM and to identify barriers to ABPM in this pediatric patient population.

METHOD

In this retrospective analysis of patients with CKD stage 3-5 who were seen in one academic medical center's outpatient Pediatric Nephrology clinics between 2018 and 2021, we performed logistic regression to evaluate for associations between demographic factors and odds of having an ABPM.

RESULT

Among 96 patients included in the study, 48 patients carried a diagnosis of hypertension. 31 patients had ABPM performed with usable data. In those who had ABPM done, 21 had normotension and 10 had undertreated hypertension. Our study also showed 1 had masked hypertension and 5 had white coat hypertension or effect. We did not find a statistically significant difference in those who did or did not undergo ABPM evaluation based on gender, previous diagnosis of hypertension, distance from clinic, language preference, or racial or ethnic identity.

CONCLUSION

ABPM is a useful tool in our CKD population for the diagnosis and management of hypertension. We did not identify specific barriers to ABPM in our CKD population, and there were no differences in patients who obtained ABPM when looking at specific demographic and disease characteristics. Given these findings, we recommend focusing on areas of future improvement in spheres of patient and provider education as well as better quantification using surveys to further illuminate barriers.

Hyperkalemia in pediatric chronic kidney disease

BACKGROUND

While hyperkalemia is well described in adult chronic kidney disease (CKD), large studies evaluating potassium trends and risk factors for hyperkalemia in pediatric CKD are lacking. This study aimed to characterize hyperkalemia prevalence and risk factors in pediatric CKD.

METHODS

Cross-sectional analysis of Chronic Kidney Disease in Children (CKiD) study data evaluated median potassium levels and percentage of visits with hyperkalemia (K ≥5.5 mmoL/L) in relation to demographics, CKD stage, etiology, proteinuria, and acid-base status. Multiple logistic regression was used to identify risk factors for hyperkalemia.

RESULTS

One thousand and fifty CKiD participants with 5183 visits were included (mean age 13.1 years, 62.7% male, 32.9% self-identifying as African American or Hispanic). A percentage of 76.6% had non-glomerular disease, 18.7% had CKD stage 4/5, 25.8% had low CO2, and 54.2% were receiving ACEi/ARB therapy. Unadjusted analysis identified a median serum potassium level of 4.5 mmol/L (IQR 4.1-5.0, p <0.001) and hyperkalemia in 6.6% of participants with CKD stage 4/5. Hyperkalemia was present in 14.3% of visits with CKD stage 4/5 and glomerular disease. Hyperkalemia was associated with low CO2 (OR 7.72, 95%CI 3.05-19.54), CKD stage 4/5 (OR 9.17, 95%CI 4.02-20.89), and use of ACEi/ARB therapy (OR 2.14, 95%CI 1.36-3.37). Those with non-glomerular disease were less frequently hyperkalemic (OR 0.52, 95%CI 0.34-0.80). Age, sex, and race/ethnicity were not associated with hyperkalemia.

CONCLUSIONS

Hyperkalemia was observed more frequently in children with advanced stage CKD, glomerular disease, low CO2, and ACEi/ARB use. These data can help clinicians identify high-risk patients who may benefit from earlier initiation of potassium-lowering therapies. A higher resolution version of the Graphical abstract is available as Supplementary information.

Chronic Kidney Disease Burden in Low-Resource Settings: Regional Perspectives

The burden of chronic kidney disease (CKD) has increased exponentially worldwide but more so in low- and middle-income countries. Specific risk factors in these regions expose their populations to an increased risk of CKD, such as genetic risk with APOL1 among populations of West African heritage or farmers with CKD of unknown etiology that spans various countries across several continents to immigrant/indigenous populations in both low- and high-income countries. Low- and middle-income economies also have the double burden of communicable and noncommunicable diseases, both contributing to the high prevalence of CKD. The economies are characterized by low health expenditure, sparse or nonexistent health insurance and welfare programs, and predominant out-of-pocket spending for medical care. This review highlights the challenges in populations with CKD from low-resource settings globally and explores how health systems can help ameliorate the CKD burden.

Anti-Hypertensive Property of an NO Nanoparticle in an Adenine-Induced Chronic Kidney Disease Young Rat Model

Hypertension is the most common complication of chronic kidney disease (CKD) in children but is still poorly controlled. Nitric oxide (NO) deficiency plays a pivotal role in CKD and hypertension. NO is known to have health benefits, while NO typically has a short half-life and is not specifically targeted. In this study, we used a pediatric CKD model, which was induced in young rats by feeding them 0.25% adenine. We investigated two different NO donors, namely S-nitrosoglutathione (GSNO) and diethylenetriamine/NO adduct (DETA NONOate) via intraperitoneal injection at 10 mg/kg/day daily for 3 weeks. GSNO was delivered by Cu²⁺-doped zeolitic imidazolate framework (Cu/ZIF-8) nanoparticles to generate NO. As a result, we observed Cu/ZIF-8 nanoparticles were successfully loaded with GSNO and were able to release NO. Young rats fed with adenine displayed kidney dysfunction and hypertension at 9 weeks of age, which were prevented by GSNO-loaded nanoparticle or DETA NONOate treatment. GSNO-loaded nanoparticles reduced CKD-induced hypertension, which was related to an enhanced endogenous NO-generating system, reduced renal oxidative stress, and downregulated several components belonging to the classic renin-angiotensin (RAS) system. Our results cast new light on targeting NO delivery through the use of nanoparticles aiming to improve child-focused outcomes related to CKD worthy of clinical translation.

Child and caregiver perspectives on access to psychosocial and educational support in pediatric chronic kidney disease: a focus group study

BACKGROUND

Children with chronic kidney disease (CKD) generally have worse educational and psychosocial outcomes compared with their healthy peers. This can impair their ability to manage their treatment, which in turn can have long-term health consequences through to adulthood. We attempted to capture the experiences of children with CKD and to describe the perspectives of their parents and caregivers on access to educational and psychosocial support.

METHODS

Children with CKD (n = 34) and their caregivers (n = 62) were sampled via focus groups from pediatric hospitals in Australia, Canada, and the USA. Sixteen focus groups were convened and the transcripts were analyzed thematically.

RESULTS

We identified four themes: disruption to self-esteem and identity (emotional turmoil of adolescence, wrestling with the sick self, powerlessness to alleviate child's suffering, balancing normality and protection); disadvantaged by lack of empathy and acceptance (alienated by ignorance, bearing the burden alone); a hidden and inaccessible support system (excluded from formal psychological support, falling behind due to being denied special considerations); and building resilience (finding partners in the journey, moving towards acceptance of the illness, re-establishing childhood).

CONCLUSIONS

Children with CKD and their caregivers encountered many barriers in accessing psychosocial and educational support and felt extremely disempowered and isolated as a consequence. Improved availability and access to psychosocial and educational interventions are needed to improve the wellbeing and educational advancement of children with CKD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prevalence and risk factors for functional iron deficiency in children with chronic kidney disease

INTRODUCTION

Anemia in chronic kidney disease (CKD) is multifactorial. The presence of functional iron deficiency (FID), whereby, there is a block in the transport of iron from macrophage to erythroid marrow is one possible etiology. In this study, we aim to assess the prevalence and risk factors of FID in pediatric CKD.

METHODS

A cross-sectional study was performed from March to December 2018, after obtaining Institute Ethical Clearance. Children aged ≤ 12 years with CKD, with or without iron supplementation who consented were enrolled. Patients on erythropoietin or on maintenance dialysis were excluded. Details of patients and diseases characteristics were recorded. Various laboratory parameters including complete blood count, red blood cell indices, hypochromic RBC, reticulocyte hemoglobin content, and serum ferritin were measured. Appropriate statistical tests were applied.

RESULTS

Out of 174 children, 127 (73%) had structural kidney disease as an etiology of CKD, and 110 (63%) had anemia. Prevalence of anemia was 44%, 43%, 74%, 64% and 92% in CKD stage 1, 2, 3, 4 and 5, respectively. Absolute iron deficiency was found in 66 (38%) even when some children were already on iron supplementation. FID was seen in 44 (25%) and on multivariate analysis, lower estimated glomerular filtration rate and mineral bone disease are associated risk factors.

CONCLUSION

FID is present in one-fourth of our CKD cohort. It should be considered when the response to adequate measures of improving hemoglobin level fails. More studies are required to know its impact on short-term and long-term patient-related outcomes such as quality of life and mortality.

Comparison of darbepoetin alpha and recombinant human erythropoietin for treatment of anemia in pediatric chronic kidney disease: a non-inferiority trial from India

To determine whether or not Darbepoetin alpha (DA) was non-inferior to recombinant human erythropoietin (rHuEPO) in the treatment of anemia in children with chronic kidney disease (CKD) stage 3-5 (on or not on dialysis). This was a randomized, open-label, two-arm, parallel group, active-controlled, non-inferiority trial conducted at a tertiary care center in New Delhi, India. Fifty patients of either gender (aged 1-18 years) with CKD stage 3-5 (on or not on dialysis) who had baseline hemoglobin (Hb) between 9 and 12 g/dL and were on stable erythropoietin therapy for at least 8 weeks were randomized (1:1) to either continue rHuEPO or switch to DA therapy for a period of 28 weeks. Doses were titrated in the initial 23 weeks to maintain the Hb between 11 and 12 g/dL, and efficacy was assessed between weeks 24 and 28. The primary efficacy outcome was the mean change in Hb between baseline and the evaluation period. In the intention-to-treat population (n = 50), the adjusted between-group difference in mean Hb change between the baseline and the evaluation period was 0.131 g/dL (95% CI: - 0.439 to 0.719, p = 0.629). The lower limit of the two-sided 95% CI for the difference in the mean change in Hb between the two treatment groups was well above the pre-specified non-inferiority margin of - 1.0 g/dL. Similar pattern of non-inferiority was seen for per protocol population. The safety profile of DA and rHuEPO was also comparable (injection site pain:rHuEPO-3, DA-7; p-0.296).   Conclusion: DA is non-inferior to rHuEPO for the treatment of anemia of CKD (stage 3-5) in pediatric population with a comparable safety profile.   Trial registration: ClinicalTrials.gov Identifier: NCT04959578 (retrospectively registered), Date: July 13, 2021. What is Known: • Limited studies showing darbepoetin alpha is effective in children as an erythropoiesis stimulating agent. • No RCT from Indian subcontinent addressing this topic. What is New: • Darbepoetin alpha is non inferior to recombinant human erythropoietin for treatment of anemia in children with CKD stage 3-5 (on or not on dialysis) with safety comparable to recombinant human erythropoietin. • A cost reduction of approximately 8.6% per patient by shifting to darbepoetin alpha.

Multi-pollutant air pollution and renal health in Asian children and adolescents: An 18-year longitudinal study

BACKGROUND

Few studies have examined the effects of multi-pollutant air pollution on renal health, especially in children and adolescents. This study investigated the association between long-term ambient air pollution exposure and renal health in Asian children and adolescents.

METHODS

This study included 10,942 children and adolescents from Taiwan and Hong Kong between 2000 and 2017. PM_2.5, NO₂ and O₃ concentrations were estimated using satellite-based spatiotemporal regression models. Two-year average concentrations, those of the year of visit and the preceding year, were used. Linear mixed models were used to examine the association between air pollution and yearly changes in estimated glomerular filtration rate (eGFR). Cox regression models with time-dependent covariates were used to examine the association between air pollution and the development of chronic kidney disease (CKD).

RESULTS

Median age of the participants was 19 years (range: 2-25). The overall average concentration of PM_2.5, NO₂ and O₃ was 26.7 μg/m³, 44.1 μg/m³ and 51.1 μg/m³, respectively. The mean yearly change in eGFR was 0.37 μL/min/1.73 m² and the incidence rate of CKD was 6.8 per 1,000 person-years. In single-pollutant models, each 10 μg/m³ increase in PM_2.5 was associated with a 0.45 μL/min/1.73 m² [95% confidence interval (CI): 0.28-0.63] reduction in the yearly increase in eGFR and 53% [hazard ratio (HR): 1.53 (95%CI: 1.07-2.2)] greater risk of incident CKD. Each 10 μg/m³ increase in NO₂ was associated with a 7% [HR (95%CI): 1.07 (1.00-1.15)] higher risk of incident CKD, while an equivalent increase in O₃ was associated with a 19% [HR (95%CI): 0.81 (0.67-0.98)] lower risk.

CONCLUSIONS

Long-term exposure to ambient PM_2.5 and NO₂ was associated with a slower growth of eGFR and a higher risk of incident CKD in children and adolescents. Our findings suggest that air pollution control in early life is imperative to improve lifelong renal health and alleviate the CKD burden.

Cardiovascular Risks of Hypertension: Lessons from Children with Chronic Kidney Disease

Hypertension is the most common complication of chronic kidney disease (CKD) in children, having a strong association with subsequential cardiovascular disease (CVD). In pediatric CKD, a considerable percentage of children with hypertension are undiagnosed or undertreated. Prior research has evaluated structural and functional markers of subclinical CVD and biomarkers in adults with CKD, while ideal biomarkers in pediatrics are still insufficiently studied. The ultimate goal of this review is to summarize what is currently known about state of hypertension, cardiovascular risk factors, and potential CVD markers/biomarkers in children with pre-dialysis CKD. We discuss omics-related biomarkers and the pathophysiologic processes of endothelial dysfunction, kidney injury, oxidative stress and inflammation that are classified by specific biomarkers. Moreover, we illustrate the existing challenges and highlight the paucity of pediatric CKD research to evaluate these CVD biomarkers for future clinical pediatric practice. Thus, achieving clinical utility of CVD biomarkers for use in pediatric CKD remains a significant challenge requiring additional efforts.

Association of dietary inflammatory index with chronic kidney disease and kidney stones in Iranian adults: A cross-sectional study within the Ravansar non-communicable diseases cohort

Chronic inflammation plays a central role in the pathogenesis of chronic kidney disease (CKD). The association of dietary inflammatory index (DII) with CKD remains underexplored. Thus, the present study aimed to determine the association between the DII, risk of CKD, and kidney stone formation using the data from the Ravansar non-communicable diseases (RaNCD) cohort study conducted in Kermanshah, Iran. The cross-sectional study was conducted using the recruitment phase data of the RaNCD cohort study comprising 9,824 individuals with an age range of 35–65 years. Food frequency questionnaires (FFQ) were used to evaluate the association between diet and DII scores. Renal function was assessed using estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), and serum creatinine (Cr) level. CKD was defined based on eGFR. The prevalence of kidney stones was evaluated by participants’ self-report. A total of 1,791 participants (18.24%) had kidney stones, while a majority were in the first quartile (27.69%). Out of 9,824 subjects, 1,747 subjects (eGFR: 18.50 ml/min per 1.73 m2; 95% CI: 17.72–19.30) had CKD. A significant trend for eGFR across all quartiles (Qs) of DII was observed. The odds ratio of CKD in the fourth quartile (pro-inflammatory diet) was 4.38-times higher than in the first quartile (anti-inflammatory diet) of DII (95% CI = 3.58–5.36). Women were found to be more likely to have less eGFR than men in the DII Qs. Collectively, the findings indicated that consumption of a pro-inflammatory diet was associated with a high occurrence of CKD. As a matter of interest, the results also revealed that a pro-inflammatory diet had no significant correlation with kidney stone development.

Hypertension in chronic kidney disease: What lies behind the scene

Hypertension is a frequent condition encountered during kidney disease development and a leading cause in its progression. Hallmark factors contributing to hypertension constitute a complexity of events that progress chronic kidney disease (CKD) into end-stage renal disease (ESRD). Multiple crosstalk mechanisms are involved in sustaining the inevitable high blood pressure (BP) state in CKD, and these play an important role in the pathogenesis of increased cardiovascular (CV) events associated with CKD. The present review discusses relevant contributory mechanisms underpinning the promotion of hypertension and their consequent eventuation to renal damage and CV disease. In particular, salt and volume expansion, sympathetic nervous system (SNS) hyperactivity, upregulated renin–angiotensin–aldosterone system (RAAS), oxidative stress, vascular remodeling, endothelial dysfunction, and a range of mediators and signaling molecules which are thought to play a role in this concert of events are emphasized. As the control of high BP via therapeutic interventions can represent the key strategy to not only reduce BP but also the CV burden in kidney disease, evidence for major strategic pathways that can alleviate the progression of hypertensive kidney disease are highlighted. This review provides a particular focus on the impact of RAAS antagonists, renal nerve denervation, baroreflex stimulation, and other modalities affecting BP in the context of CKD, to provide interesting perspectives on the management of hypertensive nephropathy and associated CV comorbidities.

Pediatric Chronic Kidney Disease

Chronic kidney disease (CKD) in children has a significant impact on morbidity, mortality, and quality of life. The degree of renal dysfunction should be calculated using pediatric-specific formulas and the degree of CKD staged; this allows for appropriate dosing of medications based on renal function and monitoring for progression and comorbid conditions including metabolic acidosis, bone disease, anemia, cardiovascular complications, malnutrition and electrolyte abnormalities, growth failure, and psychosocial issues. Treatment strategies include treating the underlying disease and using general renal protective measures. Effective management of these complex issues requires a specialized multidisciplinary team approach.

Single Nucleotide Polymorphisms in XMN1-HBG2, HBS1L-MYB, and BCL11A and Their Relation to High Fetal Hemoglobin Levels That Alleviate Anemia

Anemia is a condition in which red blood cells and/or hemoglobin (Hb) concentrations are decreased below the normal range, resulting in a lack of oxygen being transported to tissues and organs. Those afflicted with this condition may feel lethargic and weak, which reduces their quality of life. The condition may be manifested in inherited blood disorders, such as thalassemia and sickle cell disease, whereas acquired disorders include aplastic anemia, chronic disease, drug toxicity, pregnancy, and nutritional deficiency. The augmentation of fetal hemoglobin (HbF) results in the reduction in clinical symptoms in beta-hemoglobinopathies. Several transcription factors as well as medications such as hydroxyurea may help red blood cells produce more HbF. HbF expression increases with the downregulation of three main quantitative trait loci, namely, the XMN1-HBG2, HBS1L-MYB, and BCL11A genes. These genes contain single nucleotide polymorphisms (SNPs) that modulate the expression of HbF differently in various populations. Allele discrimination is important in SNP genotyping and is widely applied in many assays. In conclusion, the expression of HbF with a genetic modifier is crucial in determining the severity of anemic diseases, and genetic modification of HbF expression may offer clinical benefits in diagnosis and disease management.

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

High blood pressure in children and adolescents: current perspectives and strategies to improve future kidney and cardiovascular health

Hypertension is one of the most common causes of preventable death worldwide. The prevalence of pediatric hypertension has increased significantly in recent decades. The cause of this is likely multifactorial, related to increasing childhood obesity, high dietary sodium intake, sedentary lifestyles, perinatal factors, familial aggregation, socioeconomic factors, and ethnic blood pressure (BP) differences. Pediatric hypertension represents a major public health threat. Uncontrolled pediatric hypertension is associated with subclinical cardiovascular disease and adult-onset hypertension. In children with chronic kidney disease (CKD), hypertension is also a strong risk factor for progression to kidney failure. Despite these risks, current rates of pediatric BP screening, hypertension detection, treatment, and control remain suboptimal. Contributing to these shortcomings are the challenges of accurately measuring pediatric BP, limited access to validated pediatric equipment and hypertension specialists, complex interpretation of pediatric BP measurements, problematic normative BP data, and conflicting society guidelines for pediatric hypertension. To date, limited pediatric hypertension research has been conducted to help address these challenges. However, there are several promising signs in the field of pediatric hypertension. There is greater attention being drawn on the cardiovascular risks of pediatric hypertension, more emphasis on the need for childhood BP screening and management, new public health initiatives being implemented, and increasing research interest and funding. This article summarizes what is currently known about pediatric hypertension, the existing knowledge-practice gaps, and ongoing research aimed at improving future kidney and cardiovascular health.

Pediatric hemodialysis access

Pediatric hemodialysis access is a demanding field. Procedures are infrequent, technically challenging, and associated with high complication and failure rates. Each procedure affects subsequent access and transplants sites. The choice is made easier and outcomes improved when access decisions are made by a multidisciplinary, pediatric, hemodialysis access team. This manuscript reviews the current literature and offers technical suggestions to improve outcomes.

Serially assessed bisphenol A and phthalate exposure and association with kidney function in children with chronic kidney disease in the US and Canada: A longitudinal cohort study

BACKGROUND

Exposure to environmental chemicals may be a modifiable risk factor for progression of chronic kidney disease (CKD). The purpose of this study was to examine the impact of serially assessed exposure to bisphenol A (BPA) and phthalates on measures of kidney function, tubular injury, and oxidative stress over time in a cohort of children with CKD.

METHODS AND FINDINGS

Samples were collected between 2005 and 2015 from 618 children and adolescents enrolled in the Chronic Kidney Disease in Children study, an observational cohort study of pediatric CKD patients from the US and Canada. Most study participants were male (63.8%) and white (58.3%), and participants had a median age of 11.0 years (interquartile range 7.6 to 14.6) at the baseline visit. In urine samples collected serially over an average of 3.0 years (standard deviation [SD] 1.6), concentrations of BPA, phthalic acid (PA), and phthalate metabolites were measured as well as biomarkers of tubular injury (kidney injury molecule-1 [KIM-1] and neutrophil gelatinase-associated lipocalin [NGAL]) and oxidative stress (8-hydroxy-2'-deoxyguanosine [8-OHdG] and F2-isoprostane). Clinical renal function measures included estimated glomerular filtration rate (eGFR), proteinuria, and blood pressure. Linear mixed models were fit to estimate the associations between urinary concentrations of 6 chemical exposure measures (i.e., BPA, PA, and 4 phthalate metabolite groups) and clinical renal outcomes and urinary concentrations of KIM-1, NGAL, 8-OHdG, and F2-isoprostane controlling for sex, age, race/ethnicity, glomerular status, birth weight, premature birth, angiotensin-converting enzyme inhibitor use, angiotensin receptor blocker use, BMI z-score for age and sex, and urinary creatinine. Urinary concentrations of BPA, PA, and phthalate metabolites were positively associated with urinary KIM-1, NGAL, 8-OHdG, and F2-isoprostane levels over time. For example, a 1-SD increase in ∑di-n-octyl phthalate metabolites was associated with increases in NGAL (β = 0.13 [95% CI: 0.05, 0.21], p = 0.001), KIM-1 (β = 0.30 [95% CI: 0.21, 0.40], p < 0.001), 8-OHdG (β = 0.10 [95% CI: 0.06, 0.13], p < 0.001), and F2-isoprostane (β = 0.13 [95% CI: 0.01, 0.25], p = 0.04) over time. BPA and phthalate metabolites were not associated with eGFR, proteinuria, or blood pressure, but PA was associated with lower eGFR over time. For a 1-SD increase in ln-transformed PA, there was an average decrease in eGFR of 0.38 ml/min/1.73 m2 (95% CI: -0.75, -0.01; p = 0.04). Limitations of this study included utilization of spot urine samples for exposure assessment of non-persistent compounds and lack of specific information on potential sources of exposure.

CONCLUSIONS

Although BPA and phthalate metabolites were not associated with clinical renal endpoints such as eGFR or proteinuria, there was a consistent pattern of increased tubular injury and oxidative stress over time, which have been shown to affect renal function in the long term. This raises concerns about the potential for clinically significant changes in renal function in relation to exposure to common environmental toxicants at current levels.

Salivary metabolome of children and adolescents under peritoneal dialysis

OBJECTIVE

To study the influence of peritoneal dialysis (PD) on the salivary metabolite profile of children and adolescents with renal failure.

MATERIALS AND METHODS

Healthy children/adolescents (n = 31; mean age: 12.18 ± 3.76) and children/adolescents subjected to PD (n = 12; mean age: 10.10 ± 4.25) were recruited. Oral health status assessed by the dmft/DMFT and Volpe-Manhold calculus indices. The ¹H spectra were acquired in a 600-MHz Bruker nuclear magnetic resonance spectrometer and were subjected to multivariate analysis using partial least squares discriminant analysis (PLS-DA), orthogonal PLS-DA (O-PLS-DA), and univariate analysis through chi-square and t tests (SPSS 20.0, IL, USA), with a significance level of p < 0.05.

RESULTS

A similar caries pattern (p = 0.57; chi-square test) was observed between the healthy (dmft = 0.72 ± 1.28 and DMFT 0.93 ± 2.30) and PD groups (dmft = 2.14 ± 3.67, DMFT 0.33 ± 0.71) and dental calculus (p > 0.05, t test). PLS-DA and O-PLS-DA were able to distinguish both groups (ACC = 0.85, R² = 0.80, Q² = 0.15). Salivary metabolites decrease in creatine, propionate, and sugar levels in the PD group and an increase in creatinine, butyrate, and lactate levels when compared with the healthy group.

CONCLUSIONS

Children and adolescents subjected to PD have a different salivary metabolic profile from that of their healthy subjects.

CLINICAL RELEVANCE

Complications of peritoneal dialysis procedures could be monitored by proper knowledge of saliva characteristics as predictors of peritonitis-related outcome. The use of metabolomics in pediatric nephrology may be an innovative methodology for the early diagnosis and monitoring of kidney diseases.

Prediction model of postnatal renal function in fetuses with lower urinary tract obstruction (LUTO)-Development and internal validation

OBJECTIVE

To develop a prediction model of postnatal renal function in fetuses with lower urinary tract obstruction (LUTO) based on fetal ultrasound parameters and amniotic fluid volume.

METHODS

Retrospective nationwide cohort study of fetuses with postnatally confirmed LUTO and known eGFR. Fetuses treated with fetal interventions such as vesico-amniotic shunting or cystoscopy were excluded. Logistic regression analysis was used to identify prognostic ultrasound variables with respect to renal outcome following multiple imputation of missing data. On the basis of these fetal renal parameters and amniotic fluid volume, a model was developed to predict postnatal renal function in fetuses with LUTO. The main study outcome was an eGFR less than 60 mL/min * 1.73 m² based on the creatinine nadir during the first year following diagnosis. Model performance was evaluated by receiver operator characteristic (ROC) curve analysis, calibration plots, and bootstrapping.

RESULTS

Hundred one fetuses with a confirmed diagnosis of LUTO were included, eGFR less than 60 was observed in 40 (39.6%) of them. Variables predicting an eGFR less than 60 mL/min * 1.73m² included the following sonographic parameters: hyperechogenicity of the renal cortex and abnormal amniotic fluid volume. The model showed fair discrimination, with an area under the ROC curve of 0.70 (95% confidence interval, 0.59-0.81, 0.66 after bootstrapping) and was overall well-calibrated.

CONCLUSION

This study shows that a prediction model incorporating ultrasound parameters such as cortical appearance and abnormal amniotic fluid volume can fairly discriminate an eGFR above or below 60 mL/min * 1.73m² . This clinical information can be used in identifying fetuses eligible for prenatal interventions and improve counseling of parents.

Treatment of infant formula with patiromer dose dependently decreases potassium concentration

BACKGROUND

Hyperkalemia is a potentially life-threatening complication of chronic kidney disease (CKD). Dietary potassium restriction is challenging in infants despite low-potassium formulas. Decreasing potassium in formula using patiromer, a new calcium-based cation exchange polymer may be one option to accomplish this; however, data confirming efficacy is lacking.

METHODS

Varying doses of patiromer were added to prepared Similac Advance and Similac PM 60/40. Measurements of potassium, calcium, sodium, magnesium, and phosphorus were obtained at baseline and at 30 min, 60 min, and 24 h following patiromer administration.

RESULTS

Following pre-treatment with patiromer, the potassium concentration of both formulas decreased. This effect was mild with the lowest dose but increased in a dose-dependent fashion. Treating for 60 min or 24 h did not yield substantially greater effects than treating for 30 min. Calcium levels increased in both formula groups, mostly in a dose-dependent fashion. Changes in magnesium, sodium, and phosphorus were also seen after patiromer pre-treatment.

CONCLUSIONS

Pre-treatment with patiromer decreases the potassium concentration of infant formula. Calcium levels increased after treatment as expected with the majority of ion exchange occurring in 30 min. Treatment of formula with patiromer shows promise as a unique option for managing hyperkalemia.

Short stature in advanced pediatric CKD is associated with faster time to reduced kidney function after transplant

BACKGROUND

Among children who receive a kidney transplant, short stature is associated with a more complicated post-transplant course and increased mortality. Short stature prior to transplant may reflect the accumulated risk of multiple factors during chronic kidney disease (CKD); however, its relationship with post-transplant kidney function has not been well characterized.

METHODS

In the Chronic Kidney Disease in Children (CKiD) cohort restricted to children who received a kidney transplant, short stature (i.e., growth failure) was defined as age-sex-specific height < 3rd percentile. The outcome was time to estimated glomerular filtration rate (eGFR) < 45 ml/min/1.73 m² after transplant. Parametric survival models, including adjustment for disease severity, socioeconomic status (SES), and parental height by inverse probability weighting, described the relative times to eGFR< 45 ml/min/1.73 m².

RESULTS

Of 138 children (median CKD duration at transplant: 13 years), 20% (28) had short stature before the transplant. The median time to eGFR < 45 ml/min/1.73 m² after kidney transplantation was 6.6 years and those with short stature had a significantly faster time to the poor outcome (log-rank p value 0.004). Children with short stature tended to have lower SES, nephrotic proteinuria, higher blood pressure, and lower mid-parental height before transplant. After adjusting for these variables, children with growth failure had 40% shorter time to eGFR < 45 ml/min/1.73 m² than those with normal stature (relative time 0.60, 95%CI 0.32, 1.03).

CONCLUSIONS

Short stature was associated with a faster time to low kidney function after transplant. SES, disease severity, and parental height partially explained the association. Clinicians should be aware of the implications of growth failure on the outcome of this unique population, while continued attempts are made to define modifiable factors that contribute to this association.

Estimated GFR at Dialysis Initiation and Mortality in Children and Adolescents

RATIONALE & OBJECTIVE

The association of estimated glomerular filtration rate (eGFR) at dialysis therapy initiation with mortality among adult dialysis patients has been greatly debated, with some studies showing no benefit from early dialysis therapy initiation. However, this association has not been well investigated in pediatric dialysis patients. The objective of this study was to evaluate the mortality risk associated with eGFR at dialysis therapy initiation in children and adolescents with kidney failure.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

9,963 incident dialysis patients aged 1 to 17 years in the US Renal Data System registry (1995-2016).

PREDICTOR

eGFRs at dialysis therapy initiation calculated using the pediatric-specific bedside Schwartz equation (<5, 5-<7, 7-<9, 9-<12, and ≥12mL/min/1.73m²).

OUTCOME

Time to all-cause death.

ANALYTICAL APPROACH

Cox proportional hazards regression adjusted for case-mix variables, height, body mass index, hemoglobin level, and serum albumin level.

RESULTS

Median eGFR was 7.8 (IQR, 5.6-10.5) mL/min/1.73m² and median age was 13 (IQR, 9-16) years. 696 deaths were observed during the median follow-up of 1.4 (IQR, 0.7-2.7) years, and overall crude mortality rate was 31 per 1,000 patient-years. There appeared to be a trend toward higher mortality risk across higher eGFRs at dialysis therapy initiation. Compared with eGFRs of 7 to <9mL/min/1.73m², eGFRs <5 and ≥12mL/min/1.73m² were associated with lower and higher mortality, with adjusted HRs of 0.57 (95% CI, 0.43-0.74) and 1.31 (95% CI, 1.05-1.65), respectively. In age-stratified analysis, there were consistent relationships among patients 6 years and older while the eGFR-mortality association was attenuated among patients younger than 6 years (P_interaction = 0.002).

LIMITATIONS

Possible errors in eGFRs due to methods for serum creatinine measurement. Unmeasured confounders related to eGFR at dialysis therapy initiation.

CONCLUSIONS

Higher eGFR at dialysis therapy initiation was associated with higher mortality risk. Further studies of eGFR at initiation are needed in pediatric dialysis patients, especially among those younger than 6 years.

Kidney Transplant in Pediatric Patient With Heart Failure: Case Report

Chronic kidney disease is defined as irreversible and progressive damage of the kidney. Chronicity is defined by the presence of renal dysfunction for at least 3 months, and renal dysfunction is defined through combinations of investigation (abnormal radiologic findings, abnormal urine or abnormal biochemistry reflecting renal dysfunction) and/or documentation of glomerular filtration rate below 60 mL/min/1.73 m². The case patient was a girl of 11 years of age, with diagnosis of chronic renal disease, of unknown cause, under renal replacement therapy with peritoneal dialysis, with progressive deterioration of general status and decrease of functional capacity and tolerance to physical activity, presence of fatigue, pulmonary congestion, retention of liquids, and edema in lower extremities, even with adjustment of medical treatment. Transplant was performed from a related living donor, without incidents or complications. The results of pediatric kidney trans plant are excellent, offering a high quality of life for recipients; many patients return to school. It is consi dered the criterion standard for the treatment of pediatric endstage renal disease with excellent allograft function and subsequent resolution of systolic dysfunction.

Response to erythropoietin in pediatric patients with chronic kidney disease: insights from an in vitro bioassay

BACKGROUND

Decreased production of erythropoietin (EPO) is a major cause of anemia associated with chronic kidney disease (CKD). Treatment with recombinant human EPO (rHuEPO) improves patients' quality of life and survival; however, there is a marked variability in response to rHuEPO. At present, no available laboratory test is capable of evaluating responsiveness to EPO treatment. The aim of the present study was to use an in vitro bioassay to estimate the effect of uremic environment on EPO-dependent erythroid cell proliferation.

METHODS

EPO-dependent human erythroleukemia cells (UT-7) were incubated with exogenous EPO (2 u/ml) and sera obtained from 60 pediatric patients (aged 1-23 years). Three groups were studied: (1) 12 children on dialysis (4 peritoneal, 8 hemodialysis); (2) 28 patients with CKD 1-5 (not on dialysis), and (3) 20 healthy children.

RESULTS

Sera from dialysis patients inhibited UT-7 cell growth compared to the CKD group and healthy controls at 48 h (p = 0.003 and p = 0.04, respectively) and 72 h of culture (p = 0.02 and p = 0.07, respectively). In 18 patients treated with rHuEPO, a significant inverse correlation was found between the EPO resistance index and cell proliferation at 48 h (p = 0.007, r = - 0.63) and 72 h (p = 0.03, r = - 0.52).

CONCLUSIONS

Our findings support the presence of erythropoiesis inhibitory substances in uremic sera. EPO/EPO-R-dependent mechanisms may play a role in inhibiting erythropoiesis. The in vitro bioassay described herein may serve as an indicator of rHuEPO responsiveness which may encourage further investigation of underlying mechanisms of EPO resistance.

Progression of chronic kidney disease in children - role of glomerular hemodynamics and interstitial fibrosis

PURPOSE OF REVIEW

The aim of this review is to provide an overview of the current advances in the understanding of the mechanisms involved in the progression of chronic kidney disease (CKD) with emphasis on the role of glomerular hemodynamics and tubulointerstitial fibrosis.

RECENT FINDINGS

Despite the varied causes of CKD, the progressive destruction of renal tissue processes through a complex common pathway. Current studies have highlighted both the role of the abnormal intrarenal hemodynamics and of the activation of fibrogenic biochemical pathway in the replacement of normal renal structure by extracellular matrix and ultimately by fibrosis. Molecular markers with the potential to contribute to the detection of tubular cell damage and tubulointerstitial fibrosis in the kidney has been identified.

SUMMARY

There is a clear need to understand and elucidate the mechanisms of progression of CKD to develop efficient therapeutic strategies to halt decline of renal function in children.

A comprehensive characterization of myocardial and vascular phenotype in pediatric chronic kidney disease using cardiovascular magnetic resonance imaging

BACKGROUND

Children with chronic kidney disease (CKD) have increased cardiovascular mortality. Identifying high-risk children who may benefit from further therapeutic intervention is difficult as cardiovascular abnormalities are subtle. Although transthoracic echocardiography may be used to detect sub-clinical abnormalities, it has well-known problems with reproducibility that limit its ability to accurately detect these changes. Cardiovascular magnetic resonance (CMR) is the reference standard method for assessing blood flow, cardiac structure and function. Furthermore, recent innovations enable the assessment of radial and longitudinal myocardial velocity, such that detection of sub-clinical changes is now possible. Thus, CMR may be ideal for cardiovascular assessment in pediatric CKD. This study aims to comprehensively assess cardiovascular function in pediatric CKD using CMR and determine its relationship with CKD severity.

METHODS

A total of 120 children (40 mild, 40 moderate, 20 severe pre-dialysis CKD subjects and 20 healthy controls) underwent CMR with non-invasive blood pressure (BP) measurements. Cardiovascular parameters measured included systemic vascular resistance (SVR), total arterial compliance (TAC), left ventricular (LV) structure, ejection fraction (EF), cardiac timings, radial and longitudinal systolic and diastolic myocardial velocities. Between group comparisons and regression modelling were used to identify abnormalities in CKD and determine the effects of renal severity on myocardial function.

RESULTS

The elevation in mean BP in CKD was accompanied by significantly increased afterload (SVR), without evidence of arterial stiffness (TAC) or increased fluid overload. Left ventricular volumes and global function were not abnormal in CKD. However, there was evidence of LV remodelling, prolongation of isovolumic relaxation time and reduced systolic and diastolic myocardial velocities.

CONCLUSION

Abnormal cardiovascular function is evident in pre-dialysis pediatric CKD. Novel CMR biomarkers may be useful for the detection of subtle abnormalities in this population. Further studies are needed to determine to prognostic value of these biomarkers.

Children's, parents' and other stakeholders' perspectives on early dietary self-management to delay disease progression of chronic disease in children: a protocol for a mixed studies systematic review with a narrative synthesis

BACKGROUND

Chronic disease of childhood may be delayed by early dietary intervention. The purpose of this systematic review is to provide decision-makers with a perspective on the role of early dietary intervention, as a form of self-management, to delay disease progression in children with early chronic disease, as described by children, parents and other stakeholders.

METHODS

The study will systematically review empirical research (qualitative, quantitative and mixed method designs), including grey literature, using a narrative synthesis. A four-stage search process will be conducted involving a scoping search, the Scottish Intercollegiate Guidelines Network (SIGN) Patient Issues search filter on MEDLINE, the search of seven databases using a chronic disease and chronic kidney disease (CKD) search strategy, and hand searching the reference lists of identified papers for additional studies. All studies retrieved during the search process will undergo a screening and selection process against the inclusion/exclusion criteria. Methodological quality of relevant studies will be assessed using a validated Mixed Studies Review scoring system, before inclusion in the review. Relevant grey literature will be assessed for methodological quality and relative importance using McGrath et al.'s framework and the Academy Health advisory committee categories, respectively. Data extraction will be guided by the Centre for Review and Dissemination guidance and Popay et al.'s work. The narrative synthesis of the findings will use elements of Popay et al.'s methodology of narrative synthesis, applying recognised tools for each of the four elements: (1) developing a theory of how the intervention works, why and for whom; (2) developing a preliminary synthesis of findings of included studies; (3) exploring relationships in the data; and (4) assessing the robustness of the synthesis.

DISCUSSION

This mixed studies systematic review with a narrative synthesis seeks to elucidate the gaps in current knowledge and generate a fresh explanation of research findings on early dietary self-management in chronic disease, with particular application to CKD, from the stakeholders' perspective. The review will provide an important platform to inform future research, identifying the facilitators and barriers to implementing early dietary interventions. Ultimately, the review will contribute vital information to inform future improvements in chronic disease. The lead author has a particular interest in CKD paediatric service delivery.

SYSTEMATIC REVIEW REGISTRATION

The review has been registered with PROSPERO (CRD42017078130).

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

Renal Function Follow-Up and Renal Recovery After Acute Kidney Injury in Critically Ill Children

OBJECTIVES

To evaluate factors associated with renal recovery from acute kidney injury in critically ill children and the extent to which serum creatinine is measured before discharge.

DESIGN

Retrospective cohort study.

SETTING

Two PICUs at tertiary centers in Montreal, QC, Canada.

PATIENTS

Children (< 18 yr old) admitted to the PICU between 2003 and 2005. Patients with end-stage renal disease, no healthcare number, died during admission, or admitted postcardiac surgery were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Acute kidney injury was defined using internationally accepted criteria (Kidney Disease: Improving Global Outcomes). Two renal recovery outcomes commonly used in the literature were evaluated: hospital discharge serum creatinine less than 1.5 and less than 1.15 times baseline. Proportions of patients with 1) serum creatinine measurements between PICU and hospital discharge and 2) renal recovery were calculated. Univariate and multivariate analyses were performed to determine factors associated with serum creatinine monitoring and nonrecovery after acute kidney injury. Of 2,033 patients included, 829 (40.8%) had serum creatinine measurements between PICU and hospital discharge. The odds of having a discharge serum creatinine measurement increased with acute kidney injury severity (stages 1, 2, 3 adjusted odds ratio [95% CI]: 1.49 [1.03-2.15], 2.52 [1.40-4.54], 7.87 [3.16-19.60], respectively). Acute kidney injury recovery was 92.5% when defined as serum creatinine less than 1.5 times baseline versus 75.9% when defined as less than 1.15 times baseline (p < 0.001). Stage 3 acute kidney injury was associated with having a discharge serum creatinine greater than or equal to 1.5 times baseline (adjusted odds ratio = 3.51 [1.33-9.19]).

CONCLUSIONS

Less than half the PICU population had serum creatinine measured before hospital discharge. More severe acute kidney injury was associated with higher likelihood of serum creatinine monitoring and lower probability of acute kidney injury recovery. Future research should address knowledge translation on post-PICU acute kidney injury follow-up before hospital discharge.

Hypertension in pediatric patients with chronic kidney disease: management challenges

In contrast to adults where hypertension is a leading cause of chronic kidney disease, in pediatrics, hypertension is predominantly a sequela, however, an important one that, like in adults, is likely associated with a more rapid decline in kidney function or progression of chronic kidney disease to end stage. There is a significant issue with unrecognized, or masked, hypertension in childhood chronic kidney disease. Recent evidence and, therefore, guidelines now suggest targeting a blood pressure of <50th percentile for age, sex, and height in children with proteinuria and chronic kidney disease. This often cannot be achieved by monotherapy and additional agents need to be added. Blockade of the renin angiotensin aldosterone system represents the mainstay of therapy, although often limited by the side effect of hyperkalemia. The addition of a diuretic, at least in the earlier stages of chronic kidney disease, might help mitigate this problem.

Metabolic acidosis is common and associates with disease progression in children with chronic kidney disease

Recent studies in adult chronic kidney disease (CKD) suggest that metabolic acidosis is associated with faster decline in estimated glomerular filtration rate (eGFR). Alkali therapies improve the course of kidney disease. Here we investigated the prevalence and determinants of abnormal serum bicarbonate values and whether metabolic acidosis may be deleterious to children with CKD. Associations between follow-up serum bicarbonate levels categorized as under 18, 18 to under 22, and 22 or more mmol/l and CKD outcomes in 704 children in the Cardiovascular Comorbidity in Children with CKD Study, a prospective cohort of pediatric patients with CKD stages 3-5, were studied. The eGFR and serum bicarbonate were measured every six months. At baseline, the median eGFR was 27 ml/min/1.73m² and median serum bicarbonate level 21 mmol/l. During a median follow-up of 3.3 years, the prevalence of metabolic acidosis (serum bicarbonate under 22 mmol/l) was 43%, 60%, and 45% in CKD stages 3, 4, and 5, respectively. In multivariable analysis, the presence of metabolic acidosis as a time-varying covariate was significantly associated with log serum parathyroid hormone through the entire follow-up, but no association with longitudinal growth was found. A total of 211 patients reached the composite endpoint (ESRD or 50% decline in eGFR). In a multivariable Cox model, children with time-varying serum bicarbonate under 18 mmol/l had a significantly higher risk of CKD progression compared to those with a serum bicarbonate of 22 or more mmol/l (adjusted hazard ratio 2.44; 95% confidence interval 1.43-4.15). Thus, metabolic acidosis is a common complication in pediatric patients with CKD and may be a risk factor for secondary hyperparathyroidism and kidney disease progression.

Proteinuria and progression of pediatric chronic kidney disease: lessons from recent clinical studies

Proteinuria in children with chronic kidney disease (CKD) is common and its etiology differs from that in adults. How proteinuria influences the rate of progression of CKD has been analyzed in multiple retrospective clinical studies and more recently in a few prospective ones. In this review I summarize the results, strengths and weaknesses of each of these studies. The findings of several retrospective studies in children with CKD have confirmed what we have learned from adult studies on the association between proteinuria and worsening kidney function. Larger prospective clinical studies have examined the effects of proteinuria on the rate of decline of kidney function and the risk of end-stage kidney disease. They have also considered children with glomerular and, more importantly, the more common, congenital causes of CKD. Current studies have important strengths but also a few weaknesses that limit the validity of the conclusions which can be drawn. There is still a need for large clinical trials that focus primarily on studying the influence of proteinuria on kidney function and on finding remedies that delay progression.

Lack of hepcidin ameliorates anemia and improves growth in an adenine-induced mouse model of chronic kidney disease

Growth delay is common in children with chronic kidney disease (CKD), often associated with poor quality of life. The role of anemia in uremic growth delay is poorly understood. Here we describe an induction of uremic growth retardation by a 0.2% adenine diet in wild-type (WT) and hepcidin gene (Hamp) knockout (KO) mice, compared with their respective littermates fed a regular diet. Experiments were started at weaning (3 wk). After 8 wk, blood was collected and mice were euthanized. Adenine-fed WT mice developed CKD (blood urea nitrogen 82.8 ± 11.6 mg/dl and creatinine 0.57 ± 0.07 mg/dl) and were 2.1 cm shorter compared with WT controls. WT adenine-fed mice were anemic and had low serum iron, elevated Hamp, and elevated IL6 and TNF-α. WT adenine-fed mice had advanced mineral bone disease (serum phosphorus 16.9 ± 3.1 mg/dl and FGF23 204.0 ± 115.0 ng/ml) with loss of cortical and trabecular bone volume seen on microcomputed tomography. Hamp disruption rescued the anemia phenotype resulting in improved growth rate in mice with CKD, thus providing direct experimental evidence of the relationship between Hamp pathway and growth impairment in CKD. Hamp disruption ameliorated CKD-induced growth hormone-insulin-like growth factor 1 axis derangements and growth plate alterations. Disruption of Hamp did not mitigate the development of uremia, inflammation, and mineral and bone disease in this model. Taken together, these results indicate that an adenine diet can be successfully used to study growth in mice with CKD. Hepcidin appears to be related to pathways of growth retardation in CKD suggesting that investigation of hepcidin-lowering therapies in juvenile CKD is warranted.

Childhood Albuminuria and Chronic Kidney Disease is Associated with Mortality and End-Stage Renal Disease

BACKGROUND

We do not yet fully grasp the significance of childhood albuminuria. Based on mass urinary screening (MUS) using albumin-specific dipsticks in school children, we studied the independent association of estimated glomerular filtration rate (eGFR) and albuminuria with mortality and end-stage renal disease (ESRD) in children with chronic kidney disease (CKD).

METHODS

A prospective cohort of 5351 children with albuminuria detected by school MSU during the period 1992-1996, followed up to 2009.

RESULTS

Cumulative mortality rate, prevalence of CKD, and ESRD were higher in children with albuminuria than those without. Albuminuria category was associated with the risk of mortality [hazard ratio (HR) 3.4] and ESRD (HR 3.24). Lower eGFR and albuminuria predicted mortality and ESRD among children with albuminuria and CKD. We found that being below a threshold of 45 mL/min/1.73 m(2) was significantly associated with ESRD. The highest renal function decline, along with the steepest slope of cumulative ESRD number, occurred in Stage 3, the critical point in renal progression. Risk factors for renal progression among different age groups with albuminuria were hypercholesterolemia and low serum albumin at 7-17 years of age. Beyond 18 years of age, besides the risk factor, a higher fasting blood sugar (BS) was also noted.

CONCLUSION

Childhood albuminuria is a risk factor for CKD in later life, albuminuria provides additional prognostic information, and complications of CKD should be defined in each case.

Effect of elevated blood pressure on quality of life in children with chronic kidney disease

BACKGROUND

Although hypertension is known to have an adverse impact on health-related quality of life (HRQoL) in adults, little is known about the effects of hypertension and use of antihypertensive medications on HRQoL in hypertensive children with chronic kidney disease (CKD).

METHODS

Cross-sectional and longitudinal assessment of impact of elevated blood pressure (BP) and antihypertensive medication use on HRQoL scores obtained in children enrolled in the Chronic Kidney Disease in Children (CKiD) Study. Blood pressure was measured both manually and by ambulatory blood pressure monitoring. HRQoL was assessed with the PedsQL survey.

RESULTS

The study sample included 551 participants with sufficient data for cross-sectional and longitudinal analyses. Cross-sectional analysis of presence of prehypertension or hypertension and impact on HRQoL found mild associations between elevated BP and HRQoL scores with overall PedsQL parent and child scores averaging 79 vs. 76.5 and 83 vs. 78.5, respectively. However, no associations persisted under longitudinal multivariate analysis.

CONCLUSIONS

Despite apparent small effects of elevated BP on HRQoL at baseline, no association was found between the presence of elevated BP and HRQoL over time in children with mild-to-moderate CKD. In addition, antihypertensive medication use did not appear to have an impact on HRQoL in this population.

Clinical characteristics and prevalence of complications of chronic kidney disease in children: the Taiwan Pediatric Renal Collaborative study

BACKGROUND

Little information is available regarding the clinical characteristics and prevalence of complications in children with chronic kidney disease (CKD), especially in early disease stages. The objective of this study was to determine the clinical characteristics and prevalence of complications in children with predialytic CKD.

METHODS

This multicenter, cross-sectional study enrolled children at all stages of predialytic CKD. Children who were between the ages of 1 year and 18 years and who fulfilled the clinical criteria of CKD were included in the study. Baseline demographic data, previous history, clinical characteristics, and laboratory data were collected.

RESULTS

A total of 757 children were included in the study. The median age at the time of enrollment was 10.6 years; 397 patients (52.4 %) were males. A total of 39.0 % of the patients were in CKD stage 1, 37.6 % were in stage 2, 14.8 % were in stage 3, 3.0 % were in stage 4, and 5.5 % were in stage 5. Nonglomerular renal diseases were the primary cause of CKD, comprising 51.9 % of the patients with CKD. The age at disease onset, gender, CKD stage distribution, and proportion of co-morbidities varied between the glomerular and nonglomerular CKD cases. Anemia, hyperlipidemia, hypocalcemia, and hyperphosphatemia were more prevalent in patients with glomerular CKD. The overall prevalence of complications was as follows: uncontrolled blood pressure, 44.1 %; anemia, 34.2 %; hyperlipidemia, 44.9 %; short stature, 10.3 %; and failure to thrive, 8.2 %. Uncontrolled blood pressure (BP), anemia, and hyperlipidemia were common, even in the early CKD stages. The prevalence of CKD complications generally increased with the worsening stage of CKD.

CONCLUSIONS

This study reveals differences in CKD etiology and prevalence of specific complications according to the stage of CKD. Early recognition and awareness of complications are mandatory for clinicians during the follow-up visits of children with CKD.

Developmental changes of MPA exposure in children

BACKGROUND

Developmental changes (ontogeny) of drug disposition of Mycophenolate mofetil (MMF) have been understudied.

METHODS

The charts of 37 pediatric renal transplant recipients (median age 7.3 years, median follow-up 7.8 (IQR 6.6, 14.3 years) who had regular mycophenolic acid (MPA) trough level monitoring in combination with tacrolimus (n = 31) or sirolimus (n = 6) therapy were analyzed retrospectively for their dose-normalized MPA exposure, steroid dose, albumin, hematocrit, and cystatin C estimated glomerular filtration rate (eGFR). Using appropriate univariate and multivariate methods, we determined whether MPA exposure was age dependent when controlling for the confounders.

RESULTS

Dose-normalized MPA trough levels could be calculated in 2,128 (median 45/patient) instances. Spearman rank correlation analysis revealed that age correlated with dose-normalized MPA trough level for both body weight and body surface area, as well as serum albumin, hematocrit, steroid dose, and eGFR. In the multivariate analysis, serum albumin and steroid dose were not significant, and hematocrit only being significant when the youngest group of patients < 6 years of age was compared. eGFR was the most important confounder, but age dependency remained significant when controlling for all confounders.

CONCLUSIONS

Small children are at a significantly greater risk for low MPA trough levels than adolescents, highlighting the need for pharmacokinetic monitoring of MPA.

Revisiting post-infectious glomerulonephritis in the emerging era of C3 glomerulopathy

Background

Post-infectious glomerulonephritis (PIGN) is an immune complex-mediated glomerular injury that typically resolves. Dominant C3 deposition is characteristic of PIGN, but with the emergence of C3 glomerulonephritis (C3GN) as a distinct entity, it is unclear how the pathologic similarities between PIGN and C3GN should be reconciled. Therefore, nephrologists and nephropathologists need additional guidance at the time of biopsy.

Methods

We studied 23 pediatric and young adult patients diagnosed with PIGN. Patients were divided into two groups, one with co-dominance between C3 and immunoglobulins and the other meeting proposed diagnostic criteria for C3GN. Clinical and pathological features were compared.

Results

No clinical and/or pathological features could distinguish between those with C3-co-dominant deposits and those with C3 dominance. Nearly all patients in both groups regained their baseline renal function without clinical intervention.

Conclusions

Although the identification of abnormalities of the alternative pathway of complement is characteristic of C3GN, testing is not widely available and the turnaround time often exceeds 1 month. Our study found that PIGN with either co-dominant or dominant C3 deposition in a cohort of young patients has excellent short-term outcomes. Close clinical observation for persistent abnormalities, such as hypocomplementemia, prolonged hematuria or proteinuria, is recommended to single out patients that may harbor intrinsic complement abnormalities.

Safety and usage of darbepoetin alfa in children with chronic kidney disease: prospective registry study

BACKGROUND

Limited prospective data are available on the long-term safety of darbepoetin alfa (DA) for treating anemia in children with chronic kidney disease (CKD).

METHODS

In this prospective, phase IV, observational registry study, children ≤16 years of age with CKD anemia and receiving DA were observed for ≤2 years. Adverse events (AEs), DA dosing, hemoglobin (Hb) concentrations, and transfusions were recorded.

RESULTS

A total of 319 patients were included in the analysis (mean age, 9.1 years), 158 (49.5%) of whom were on dialysis at study entry. Of 434 serious AEs reported in 162 children, the most common were peritonitis (10.0%), gastroenteritis (6.0%), and hypertension (4.1%). Six patients (1.9%) died (unrelated to DA). Four patients (1.3%) experienced six serious adverse drug reactions. The geometric mean DA dose range was 1.4-2.0 μg/kg/month. Mean baseline Hb concentration was 11.1 g/dl; mean values for children receiving and not receiving dialysis at baseline ranged between 10.9 and 11.5 g/dl and 11.2-11.7 g/dl, respectively. Overall, 48 patients (15.0%) received ≥1 transfusion.

CONCLUSIONS

No new safety signals for DA were identified in children receiving DA for CKD anemia for ≤2 years. Based on Hb concentrations and transfusion requirements, DA was effective at managing anemia in these patients.

Role of 24-h ambulatory blood pressure monitoring in children with chronic kidney disease

Hypertension is common in children with chronic kidney disease (CKD) and is a major determinant of CKD progression. Ambulatory blood pressure monitoring (ABPM) has been proposed to be better in detecting hypertension as compared to casual blood pressure (CBP). This study aims to study the usefulness of ABPM in detecting masked hypertension, evaluating the adequacy of blood pressure (BP) control and predicting left ventricular hypertrophy (LVH) amongst children with CKD. A prospective cross-sectional study of 46 children with stage 3–5 CKD was conducted at the Pediatric Nephrology department of a tertiary hospital in South India. All children underwent CBP, ABPM and an echocardiography. Results were categorized as normal BP; confirmed hypertension; masked hypertension and white coat hypertension. Out of 46 children studied, 11 were undergoing dialysis. While 39.1% children had stage 3 and 4 CKD each, 21.7% had stage 5 CKD. Masked hypertension was detected in 19.6% and 21.7% had confirmed hypertension. Thirty-four (73.9%) children were already receiving antihypertensive medication. In these, CBP was elevated in 23.5% and ABP in 47%. Among children with hypertension as defined by ABPM, LVH was detected in 32.2%. We found that higher the number of abnormal ABPM indices (assessed by BP Index, nocturnal dipping and BP Load) higher the likelihood of LVH (P = 0.046). ABPM is better in detecting hypertension and monitoring adequacy of treatment in children with CKD. The high prevalence of masked hypertension and its association with LVH supports early echocardiography and ambulatory BP monitoring to evaluate cardiovascular risks in this population.

Pre-treatment considerations in childhood hypertension due to chronic kidney disease

Hypertension (HTN) develops very early in childhood chronic kidney disease (CKD). It is linked with rapid progression of kidney disease, increased morbidity and mortality hence the imperative to start anti-hypertensive medication when blood pressure (BP) is persistently > 90^th percentile for age, gender, and height in non-dialyzing hypertensive children with CKD. HTN pathomechanism in CKD is multifactorial and complexly interwoven. The patient with CKD-associated HTN needs to be carefully evaluated for co-morbidities that frequently alter the course of the disease as successful treatment of HTN in CKD goes beyond life style modification and anti-hypertensive therapy alone. Chronic anaemia, volume overload, endothelial dysfunction, arterial media calcification, and metabolic derangements like secondary hyperparathyroidism, hyperphosphataemia, and calcitriol deficiency are a few co-morbidities that may cause or worsen HTN in CKD. It is important to know if the HTN is caused or made worse by the toxic effects of medications like erythropoietin, cyclosporine, tacrolimus, corticosteroids and non-steroidal anti-inflammatory drugs. Poor treatment response may be due to any of these co-morbidities and medications. A satisfactory hypertensive CKD outcome, therefore, depends very much on identifying and managing these co-morbid conditions and HTN promoting medications promptly and appropriately. This review attempts to point attention to factors that may affect successful treatment of the hypertensive CKD child and how to attain the desired therapeutic BP target.

Neurocognitive Dysfunction in Children, Adolescents, and Young Adults With CKD

BACKGROUND

Neurocognitive dysfunction is a known complication in children with chronic kidney disease (CKD). However, less is known about putative mechanisms or modifiable risk factors. The objective of this study was to characterize and determine risk factors for cognitive dysfunction in children, adolescents, and young adults with CKD compared with controls.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

The Neurocognitive Assessment and Magnetic Resonance Imaging Analysis of Children and Young Adults With Chronic Kidney Disease (NiCK) Study included 90 individuals aged 8 to 25 years with CKD compared with 70 controls.

PREDICTORS

CKD versus control, estimated glomerular filtration rate (eGFR), ambulatory blood pressure.

OUTCOMES

Performance on neurocognitive assessment with relevant tests grouped into 11 domains defined a priori by expert opinion. Results of tests were converted to age-normalized z scores.

MEASUREMENTS

Each neurocognitive domain was analyzed through linear regression, adjusting for eGFR and demographic and clinical variables. For domains defined by multiple tests, the median z score of tests in that domain was used.

RESULTS

We found significantly poorer performance in multiple areas of neurocognitive function among individuals with CKD compared with controls. Particular deficits were seen in domains related to attention, memory, and inhibitory control. Adjusted for demographic and clinical factors, we found lower performance in multiple domains with decreasing eGFRs (attention: β=0.053, P=0.02; visual spatial: β=0.062, P=0.02; and visual working memory: β=0.069, P=0.04). Increased diastolic load and decreased diastolic nocturnal dipping on ambulatory blood pressure monitoring were independently associated with impairments in neurocognitive performance.

LIMITATIONS

Unable to assess changes in neurocognitive function over time, and neurocognitive tests were grouped into predetermined neurocognitive domains.

CONCLUSIONS

Lower eGFR in children, adolescents, and young adults is associated with poorer neurocognitive performance, particularly in areas of attention, memory, and inhibitory control. Hypertension identified on ambulatory blood pressure monitoring may be an important risk factor, illustrating that neurocognitive function is an area of target-organ damage in CKD.

Decreased arterial elasticity in children with nondialysis chronic kidney disease is related to blood pressure and not to glomerular filtration rate

We compared large artery mechanical properties in children with nondialysis stages of chronic kidney disease with those in children with normal renal function, examining the potential effect of blood pressure (BP) components and level of renal dysfunction. Common carotid artery mechanical properties, carotid-femoral pulse wave velocity, and carotid and peripheral BP were measured in children (n=226) with nondialysis chronic kidney disease (n=188; 11.9±3.7 years; 26%, 25%, 30%, 16%, and 3% in stages 1, 2, 3, 4 and 5, respectively) and healthy controls (n=38; 11.5±3.3 years). In children with nondialysis chronic kidney disease when compared with healthy controls, at similar levels of peripheral and carotid BP, carotid artery diastolic diameter and wall thickness were similar. In those with suboptimal BP (≥75th percentile), indices of arterial elasticity indicated greater stiffness than in healthy normotensive controls (distensibility: 92±31 versus 114±33 kPa(-1)×10(-3), P=0.03; compliance: 2.1±0.7 versus 2.6±0.7 m(2) kPa(-1)×10(-6), P=0.02; Young elastic modulus: 0.151±0.068 versus 0.109±0.049 kPa×10(3), P=0.02; and wall stress: 83.6±23.5 versus 68.7±14.9 kPa, P=0.02). In all children, mechanical properties were independently related to carotid and peripheral BP components but not to estimated glomerular filtration rate. In children with nondialysis chronic kidney disease, changes in elastic properties of the carotid artery are primarily related to BP and not to glomerular renal function.

Renal formulas pretreated with medications alters the nutrient profile

BACKGROUND

Pretreating renal formulas with medications to lower the potassium and phosphorus content is common in clinical practice; however, the effect of this treatment on other nutrients is relatively unstudied. We examine whether nutrient composition is affected by pretreating renal formulas with sodium polystyrene sulfonate (SPS) suspension and sevelamer carbonate.

METHODS

Fixed medication doses and treatment times were utilized to determine changes in the nutrient composition of Suplena® and Similac® PM 60/40. The effect of simultaneously adding both medications (co-administration) to the formula on the nutrient composition of Suplena® was also evaluated.

RESULTS

Pretreatment of Suplena® with SPS reduced the concentrations of calcium (11-38 %), copper (3-11 %), manganese (3-16 %), phosphorus (0-7 %), potassium (6-34 %), and zinc (5-20 %) and increased those of iron (9-34 %), sodium (89-260 %), and sulfur (19-45 %) and the pH (0.20-0.50 units). Pretreatment of Similac® PM 60/40 with SPS reduced the concentrations of calcium (8-29 %), copper (5-19 %), magnesium (3-26 %), and potassium (33-63 %) and increased those of iron (13-87 %) and sodium (86-247 %) and the pH (0.40-0.81 units). Pretreatment of both formulas with the SPS suspension led to significant increases in the aluminum concentration in both formulas (507-3957 %). No differences in potassium concentration were observed between treatment times. Unexpectedly, the levels of neither phosphorus nor potassium were effectively reduced in Suplena® pretreated with sevelamer carbonate alone or when co-administered with SPS.

CONCLUSIONS

Pretreating formula with medications alters nutrients other than the intended target(s). Future studies should be aimed at predicting the loss of these nutrients or identifying alternative methods for managing serum potassium and phosphorus levels in formula-fed infants. The safety of pretreating formula with SPS suspension should also be examined.

Hypertension in children with end-stage renal disease

This review summarizes current data on the epidemiology, pathophysiology, and treatment of hypertension (HTN) in children with end-stage renal disease (ESRD). Worldwide prevalence of ESRD ranges from 5.0 to 84.4 per million age-related population. HTN is present in 27-79% of children with ESRD, depending on the modality of renal replacement therapy and the exact definition of hypertension. Ambulatory BP monitoring has been recommended for the detection of HTN and evaluation of treatment effectiveness. HTN in dialyzed patients is mostly related to hypervolemia, sodium overload, activation of the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system, impaired nitric oxide synthesis, reduced vitamin D levels, and effects of microRNA. In children undergoing chronic dialysis therapy, important factors include optimization of renal replacement therapy and preservation of residual renal function, allowing reduction of volume- and sodium-overload, along with appropriate drug treatment, particularly with calcium channel blockers, RAAS inhibitors, and loop diuretics.