Clinical practice recommendations for treatment with active vitamin D analogues in children with chronic kidney disease Stages 2-5 and on dialysis

Assessment and management of vitamin status in children with CKD stages 2-5, on dialysis and post-transplantation: clinical practice points from the Pediatric Renal Nutrition Taskforce

Children with chronic kidney disease (CKD) are at risk for vitamin deficiency or excess. Vitamin status can be affected by diet, supplements, kidney function, medications, and dialysis. Little is known about vitamin requirements in CKD, leading to practice variation.The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric kidney dietitians and pediatric nephrologists, was established to develop evidence-based clinical practice points (CPPs) to address challenges and to serve as a resource for nutritional care. Questions were formulated using PICO (Patient, Intervention, Comparator, Outcomes), and literature searches undertaken to explore clinical practice from assessment to management of vitamin status in children with CKD stages 2-5, on dialysis and post-transplantation (CKD2-5D&T). The CPPs were developed and finalized using a Delphi consensus approach. We present six CPPs for vitamin management for children with CKD2-5D&T. We address assessment, intervention, and monitoring. We recommend avoiding supplementation of vitamin A and suggest water-soluble vitamin supplementation for those on dialysis. In the absence of evidence, a consistent structured approach to vitamin management that considers assessment and monitoring from dietary, physical, and biochemical viewpoints is needed. Careful consideration of the impact of accumulation, losses, comorbidities, and medications needs to be explored for the individual child and vitamin before supplementation can be considered. When supplementing, care needs to be taken not to over-prescribe. Research recommendations are suggested.

Nutritional management of the child with chronic kidney disease and on dialysis

While it is widely accepted that the nutritional management of the infant with chronic kidney disease (CKD) is paramount to achieve normal growth and development, nutritional management is also of importance beyond 1 year of age, particularly in toddlers, to support the delayed infantile stage of growth that may extend to 2-3 years of age. Puberty is also a vulnerable period when nutritional needs are higher to support the expected growth spurt. Inadequate nutritional intake throughout childhood can result in failure to achieve full adult height potential, and there is an increased risk for abnormal neurodevelopment. Conversely, the rising prevalence of overweight and obesity among children with CKD underscores the necessity for effective nutritional strategies to mitigate the risk of metabolic syndrome that is not confined to the post-transplant population. Nutritional management is of primary importance in improving metabolic equilibrium and reducing CKD-related imbalances, particularly as the range of foods eaten by the child widens as they get older (including increased consumption of processed foods), and as CKD progresses. The aim of this review is to integrate the Pediatric Renal Nutrition Taskforce (PRNT) clinical practice recommendations (CPRs) for children (1-18 years) with CKD stages 2-5 and on dialysis (CKD2-5D). We provide a holistic approach to the overall nutritional management of the toddler, child, and young person. Collaboration between physicians and pediatric kidney dietitians is strongly advised to ensure comprehensive and tailored nutritional care for children with CKD, ultimately optimizing their growth and development.

Safety and Efficacy of Cinacalcet in Children Aged Under 3 Years on Maintenance Dialysis

Introduction

Secondary hyperparathyroidism (sHPT) is particularly severe in rapidly growing infants in dialysis. Although cinacalcet is effective and licensed in dialysis in children aged >3 years, its efficacy and safety for children aged <3 years is unknown.

Methods

We identified 26 children aged <3 years who were on dialysis and treated with cinacalcet between 2009 and 2021 in 8 European pediatric centers.

Results

Median (interquartile range) age at the start of cinacalcet was 18 (interquartile range: 11-27) months, serum parathyroid hormone (PTH) was 792 (411-1397) pg/ml, corresponding to 11.6 (5.9-19.8) times the upper limit of normal (ULN). Serum calcium was 2.56 (2.43-2.75) mmol/l, and serum phosphate 1.47 (1.16-1.71) mmol/l. Serum 25-OH vitamin D (25-OHD) was 70 (60-89) nmol/l, 3 children were vitamin D deficient (<50 nmol/l). The initial cinacalcet dose was 0.4 (0.2-0.8) mg/kg/d and the maximum dose was 1.1 (0.6-1.2) mg/kg/d. The median follow-up under cinacalcet was 1.2 (0.7-2.0) years. PTH decreased to 4.3 (2.2-7.8) times the ULN after 6 months, to 2.0 (1.0-5.3) times ULN after 12 months, and to 1.6 (0.5-3.4) times thereafter (P = 0.017/0.003/<0.0001, log-transformed PTH). Seven of the 26 infants developed 10 hypocalcemic episodes <2.10 mmol/l. Oral calcium intake was 84% (66%-117%) of recommended nutrient intake at start, 100% (64%-142%) at 3 months and declined to 78% (65%-102%) at 12 months of therapy. Three children developed clinical signs of precocious puberty.

Conclusion

Cinacalcet efficiently controlled severe sHPT in children aged <3 years and was associated with hypocalcemic episodes (similar to what is observed in older children) and precious puberty, thereby mandating meticulous control of calcium (considering nutrition, supplementation, and dialysate) and endocrine changes.

Ten tips on how to assess bone health in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) experience a several-fold increased risk of fracture. Despite the high incidence and the associated excess morbidity and premature mortality, bone fragility in CKD, or CKD-associated osteoporosis, remains a blind spot in nephrology with an immense treatment gap. Defining the bone phenotype is a prerequisite for the appropriate therapy of CKD-associated osteoporosis at the patient level. In the present review, we suggest 10 practical 'tips and tricks' for the assessment of bone health in patients with CKD. We describe the clinical, biochemical, and radiological evaluation of bone health, alongside the benefits and limitations of the available diagnostics. A bone biopsy, the gold standard for diagnosing renal bone disease, is invasive and not widely available; although useful in complex cases, we do not consider it an essential component of bone assessment in patients with CKD-associated osteoporosis. Furthermore, we advocate for the deployment of multidisciplinary expert teams at local, national, and potentially international level. Finally, we address the knowledge gaps in the diagnosis, particularly early detection, appropriate "real-time" monitoring of bone health in this highly vulnerable population, and emerging diagnostic tools, currently primarily used in research, that may be on the horizon of clinical practice.

Bone Disorders in Pediatric Chronic Kidney Disease: A Literature Review

Intense changes in mineral and bone metabolism are frequent in chronic kidney disease (CKD) and represent an important cause of morbidity and reduced quality of life. These disorders have conventionally been defined as renal osteodystrophy and classified based on bone biopsy, but due to a lack of bone biopsy data and validated radiological methods to evaluate bone morphology in children, it has been challenging to effectively assess renal osteodystrophy in pediatric CKD; the consequence has been the suboptimal management of bone disorders in children. CKD-mineral and bone disorder (CKD-MBD) is a new expression used to describe a systemic disorder of mineral and bone metabolism as a result of CKD. CKD-MBD is a triad of biochemical imbalances in calcium, phosphate, parathyroid hormone, and vitamin D; bone deformities and soft tissue calcification. This literature review aims to explore the pathogenesis, diagnostic approach, and treatment of CKD-MBD in children and the effects of renal osteodystrophy on growing skeleton, with a specific focus on the biological basis of this peculiar condition.

Diagnosis and management of mineral and bone disorders in infants with CKD: clinical practice points from the ESPN CKD-MBD and Dialysis working groups and the Pediatric Renal Nutrition Taskforce

BACKGROUND

Infants with chronic kidney disease (CKD) form a vulnerable population who are highly prone to mineral and bone disorders (MBD) including biochemical abnormalities, growth retardation, bone deformities, and fractures. We present a position paper on the diagnosis and management of CKD-MBD in infants based on available evidence and the opinion of experts from the European Society for Paediatric Nephrology (ESPN) CKD-MBD and Dialysis working groups and the Pediatric Renal Nutrition Taskforce.

METHODS

PICO (Patient, Intervention, Comparator, Outcomes) questions were generated, and relevant literature searches performed covering a population of infants below 2 years of age with CKD stages 2-5 or on dialysis. Clinical practice points (CPPs) were developed and leveled using the American Academy of Pediatrics grading matrix. A Delphi consensus approach was followed.

RESULTS

We present 34 CPPs for diagnosis and management of CKD-MBD in infants, including dietary control of calcium and phosphate, and medications to prevent and treat CKD-MBD (native and active vitamin D, calcium supplementation, phosphate binders).

CONCLUSION

As there are few high-quality studies in this field, the strength of most statements is weak to moderate, and may need to be adapted to individual patient needs by the treating physician. Research recommendations to study key outcome measures in this unique population are suggested. A higher resolution version of the Graphical abstract is available as Supplementary information.

Understanding Similarities and Differences in CKD and Dialysis Care in Children and Adults

In lower-income settings there is often a dearth of resources and nephrologists, especially pediatric nephrologists, and individual physicians often find themselves caring for patients with chronic kidney diseases and end-stage kidney failure across the age spectrum. The management of such patients in high-income settings is relatively protocolized and permits high-volume services to run efficiently. The basic principles of managing chronic kidney disease and providing dialysis are similar for adults and children, however, given the differences in body size, causes of kidney failure, nutrition, and growth between children and adults with kidney diseases, nephrologists must understand the relevance of these differences, and have an approach to providing quality and safe dialysis to each group. Prevention, early diagnosis, and early intervention with simple therapeutic and lifestyle interventions are achievable goals to manage symptoms, complications, and reduce progression, or avoid kidney failure in children and adults. These strategies currently are easier to implement in higher-resource settings with robust health systems. In many low-resource settings, kidney diseases are only first diagnosed at end stage, and resources to pay out of pocket for appropriate care are lacking. Many barriers therefore exist in these settings, where specialist nephrology personnel may be least accessible. To improve management of patients at all ages, we highlight differences and similarities, and provide practical guidance on the management of children and adults with chronic kidney disease and kidney failure. It is important that children are managed with a view to optimizing growth and well-being and maximizing future options (eg, maintaining vein health and optimizing cardiovascular risk), and that adults are managed with attention paid to quality of life and optimization of physical health.

Improving Clinical Care for Children With CKD: A Report From a National Kidney Foundation Scientific Workshop

Development of clinical guidelines and recommendations to address the care of pediatric patients with chronic kidney disease (CKD) has rarely included the perspectives of providers from a variety of health care disciplines or the patients and parents themselves. Accordingly, the National Kidney Foundation hosted an in-person, one and a half-day workshop that convened a multidisciplinary group of physicians, allied health care professionals, and pediatric patients with CKD and their parents, with the goal of developing key clinical recommendations regarding best practices for the clinical management of pediatric patients living with CKD. The key clinical recommendations pertained to 5 broad topics: addressing the needs of patients and parents/caregivers; modifying the progression of CKD; clinical management of CKD-mineral and bone disorder and growth retardation; clinical management of anemia, cardiovascular disease, and hypertension; and transition and transfer of pediatric patients to adult nephrology care. This report describes the recommendations generated by the participants who attended the workshop.

The clinical relevance of native vitamin D in pediatric kidney disease

Hypovitaminosis D has been reported to be common in chronic kidney disease (CKD) as well as in proteinuric disorders. We reviewed available evidence to assess clinically relevant effects of low vitamin D status and native vitamin D (NVD) therapy, in pediatric renal diseases. Online medical databases were searched for articles related to vitamin D status, associations of hypovitaminosis D and effects of NVD therapy in kidney disease. Hypovitaminosis D was associated with worse skeletal, cardiovascular, inflammatory, and renal survival outcomes in CKD. Low serum 25 hydroxy-vitamin D (25[OH]D) levels correlated positively with glomerular filtration rate and negatively with serum parathyroid (PTH) levels. However, to date, evidence of benefit of NVD supplementation is restricted mainly to improvements in serum PTH, and biochemical 25[OH]D targets form the basis of clinical practice recommendations for NVD therapy. In nephrotic syndrome (NS) relapse, studies indicate loss of 25[OH]D along with vitamin D binding protein in urine, and serum total 25[OH]D levels are low. Preliminary evidence indicates that free 25[OH]D may be a better guide to the biologically active fraction. NVD therapy in NS does not show consistent results in improving skeletal outcomes and hypercalciuria has been reported when total 25[OH]D levels were considered as indication for therapy. NVD formulations should be regularised, and therapy monitored adequately to avoid adverse effects.

Nutritional management of the infant with chronic kidney disease stages 2-5 and on dialysis

The nutritional management of children with chronic kidney disease (CKD) is of prime importance in meeting the challenge of maintaining normal growth and development in this population. The objective of this review is to integrate the Pediatric Renal Nutrition Taskforce clinical practice recommendations for children with CKD stages 2-5 and on dialysis, as they relate to the infant from full term birth up to 1 year of age, for healthcare professionals, including dietitians, physicians, and nurses. It addresses nutritional assessment, energy and protein requirements, delivery of the nutritional prescription, and necessary dietary modifications in the case of abnormal serum levels of calcium, phosphate, and potassium. We focus on the particular nutritional needs of infants with CKD for whom dietary recommendations for energy and protein, based on body weight, are higher compared with children over 1 year of age in order to support both linear and brain growth, which are normally maximal in the first 6 months of life. Attention to nutrition during infancy is important given that growth is predominantly nutrition dependent in the infantile phase and the growth of infants is acutely impaired by disruption to their nutritional intake, particularly during the first 6 months. Inadequate nutritional intake can result in the failure to achieve full adult height potential and an increased risk for abnormal neurodevelopment. We strongly suggest that physicians work closely with pediatric renal dietitians to ensure that the infant with CKD receives the best possible nutritional management to optimize their growth and development.

Chronic Kidney Disease in Children

Chronic kidney disease (CKD) in children occurs mostly due to congenital anomalies of kidney and urinary tract and hereditary diseases. For advanced cases, a multidisciplinary team is needed to manage nutritional requirements and complications such as hypertension, hyperphosphatemia, proteinuria, and anemia. Neurocognitive assessment and psychosocial support are essential. Maintenance dialysis in children with end-stage renal failure has become the standard of care in many parts of the world. Children younger than 12 years have 95% survival after 3 years of dialysis initiation, whereas the survival rate for children aged 4 years or younger is about 82% at one year."

Parathormone, bone alkaline phosphatase and 25-hydroxyvitamin D status in a large cohort of 1200 children and teenagers

Objectives: 25-Hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and bone alkaline phosphatase (BALP) are biomarkers of calcium/phosphate metabolism and bone turnover. Although vitamin D deficiency is a well-known cause of secondary hyperparathyroidism, few studies have considered vitamin D status when establishing reference ranges. In this study, we report PTH levels according to the vitamin D status and BALP levels in a large cohort of 1200 children. Additionally, we provide PTH pediatric reference values according to 25(OH)D status as well as BALP pediatric reference ranges.Methods: Serum samples from 1200 children (equally distributed from 5 months to 20 years old) who underwent blood sampling for allergy exploration were used to quantify 25(OH)D, PTH and BALP.Results: The percentage of vitamin D deficient children (<20 ng/ml) progressively increased during childhood starting from 7% in the 0 to 2 year-old subgroup to a mean of at least 50% among teenagers. PTH levels inversely mirrored 25(OH)D concentrations for all age and gender subgroups, and 25(OH)D deficient subgroups presented higher PTH levels than their non-deficient counterparts. In the non-deficient 25(OH)D population, PTH levels were the highest at 11 years old for girls and 14 years old for boys. BALP results were slightly increased during childhood and showed a constant decrease during teenage years starting from 12 years old for girls and 14 years old for boys.Conclusion: Our results highlight the inverse relationship between PTH and 25(OH)D in children and the need for a well characterized 25(OH)D population to establish pediatric reference ranges for PTH.

Medication based machine learning to identify subpopulations of pediatric hemodialysis patients in an electronic health record database

Electronic health records (EHRs) have given rise to large and complex databases of medical information that have the potential to become powerful tools for clinical research. However, differences in coding systems and the detail and accuracy of the information within EHRs can vary across institutions. This makes it challenging to identify subpopulations of patients and limits the widespread use of multi-institutional databases. In this study, we leveraged machine learning to identify patterns in medication usage among hospitalized pediatric patients receiving renal replacement therapy and created a predictive model that successfully differentiated between intermittent (iHD) and continuous renal replacement therapy (CRRT) hemodialysis patients. We trained six machine learning algorithms (logistical regression, Naïve Bayes, k-nearest neighbor, support vector machine, random forest, and gradient boosted trees) using patient records from a multi-center database (n = 533) and prescribed medication ingredients (n = 228) as features to discriminate between the two hemodialysis types. Predictive skill was assessed using a 5-fold cross-validation, and the algorithms showed a range of performance from 0.7 balanced accuracy (logistical regression) to 0.86 (random forest). The two best performing models were further tested using an independent single-center dataset and achieved 84–87% balanced accuracy. This model overcomes issues inherent within large databases and will allow us to utilize and combine historical records, significantly increasing population size and diversity within both iHD and CRRT populations for future clinical studies. Our work demonstrates the utility of using medications alone to accurately differentiate subpopulations of patients in large datasets, allowing codes to be transferred between different coding systems. This framework has the potential to be used to distinguish other subpopulations of patients where discriminatory ICD codes are not available, permitting more detailed insights and new lines of research.

Local protocol helped to deliver vitamin D levels more accurately in preterm infants

AIM

This study retrospectively evaluated the effectiveness and safety of a local hospital protocol of vitamin D supplementation for preterm infants, which was modified in 2016.

METHODS

We focussed on 99 preterm infants born before 31 weeks of gestation and admitted to the neonatal intensive care unit at the Femme Mere Enfant Hospital, Bron, France, from 1 January to 31 December 2018. Calcium and urinary calcium were measured, and 25-hydroxy vitamin D (25(OH)D) levels were monitored monthly and supplementation was adjusted, with 50-120 nmol/L considered normal. The results are presented as medians and interquartile ranges.

RESULTS

The infants were enrolled at a gestational age of 28.0 [26.9-29.1] weeks and birth weight of 960 [800-1160] g. When they were discharged at 37.3 [35.2-39.8] weeks, the overall 25(OH)D level was 98 [79-140] nmol/L: 4% had low levels, 63% had normal levels and 33% had high levels. Vitamin D supplementation was withdrawn for 60% more than one month before discharge. Rickets or fractures were not reported.

CONCLUSION

The modified protocol limited underdosing and significant overdosing, but moderate hypervitaminosis D was still frequent. Urgent studies are needed to determine the optimal supplementation and clinical impact of 25(OH)D on comorbidities in preterm infants.

Peripheral Blood Mononuclear Cells (PBMCs) to Dissect the Underlying Mechanisms of Bone Disease in Chronic Kidney Disease and Rare Renal Diseases

PURPOSE OF REVIEW

To describe the methods that can be used to obtain functional and mature osteoclasts from peripheral blood mononuclear cells (PBMCs) and report the data obtained with this model in two peculiar diseases, namely pediatric chronic kidney disease-associated mineral and bone disorders (CKD-MBD) and nephropathic cystinosis. To discuss future research possibilities in the field.

RECENT FINDINGS

Bone tissue undergoes continuous remodeling throughout life to maintain bone architecture; it involves two processes: bone formation and bone resorption with the coordinated activity of osteoblasts, osteoclasts, and osteocytes. Animal models fail to fully explain human bone pathophysiology during chronic kidney disease, mainly due to interspecies differences. The development of in vitro models has permitted to mimic human bone-related diseases as an alternative to in vivo models. Since 1997, osteoclasts have been generated in cell cultures, notably when culturing PBMCs with specific growth factors and cytokines (i.e., M-CSF and RANK-L), without the need for osteoblasts or stromal cells. These models may improve the global understanding of bone pathophysiology. They can be been used not only to evaluate the direct effects of cytokines, hormones, cells, or drugs on bone remodeling during CKD-MBD, but also in peculiar genetic renal diseases inducing specific bone impairment.

Reducing the burden of cardiovascular disease in children with chronic kidney disease: prevention vs. damage limitation

Cardiovascular disease (CVD) is a life-limiting condition in patients with chronic kidney disease (CKD) and is rapidly progressive, especially in those with stage 5 CKD and on dialysis. Cardiovascular mortality, although reducing, remains at least 30 times higher than in the general pediatric population. The American Heart Association guidelines for cardiovascular risk reduction in high-risk pediatric patients has stratified pediatric CKD patients in the "high risk" category for the development of CVD, with associated pathological and/or clinical evidence for manifest coronary disease before 30 years of age. While improving patient survival is a key priority, other patient-related outcomes, such as psychosocial development, quality of life and growth are of major importance to children and their caregivers. Once vascular damage or calcification has developed, there are no data to suggest that they can be reversed. Treatments such as intensified dialysis and transplantation may attenuate the progression of subclinical cardiovascular disease, but no treatment to date has shown that the inexorable progression of CVD in CKD can be reversed. Thus, our management must focus on early diagnosis and robust preventative strategies to give our patients the best chance of optimal cardiovascular health and survival. In this review, the pathophysiology and importance of preventing the development of CVD in CKD is discussed.

Structural and functional insights on vitamin D receptor and CYP24A1 deleterious single nucleotide polymorphisms: A computational and pharmacogenomics perpetual approach

The development of chronic kidney disease (CKD) drugs remains a challenge due to the variations in the genes. The vitamin D receptor (VDR) and Cytochrome 24A1 (CYP24A1) genetic variants might affect the drug potency, efficacy and pathway. Here we have to analyse and determine the deleterious single-nucleotide polymorphisms (nsSNPs) of VDR and CYP24A1 genes and their different population's drug responses in different populations to understand the key role in CKD. Among that the large scale of nsSNP, we used certain computational tools that predicted six missense variants are observed to be significantly damaging effect and SNP variability with large differences in various populations. Molecular docking studies were carried out by clinical and our screened compounds to VDR and CYP24A1. Docking results revealed all the compounds have a good binding affinity (Score). The screened compounds (TCM_2868 and UNPD_141613) show good binding affinity when compared to known compounds. The QM/MM study revealed that the compounds have electron transfer ability and act as a donor/acceptor to mutated proteins. The structural and conformational changes of protein complexes were analysed by molecular dynamics study. Hence, this study helps to identify suitable drugs through drug discovery in CKD treatment. The abovementioned compounds have more binding affinity, efficacy, and potency of both wild and mutant of VDR and CYP24A1.

Active vitamin D is cardioprotective in experimental uraemia but not in children with CKD Stages 3-5

BACKGROUND

Uraemic cardiac remodelling is associated with vitamin D and Klotho deficiency, elevated fibroblast growth factor 23 (FGF23) and activation of the renin-angiotensin system (RAS). The cardioprotective properties of active vitamin D analogues in this setting are unclear.

METHODS

In rats with 5/6 nephrectomy (5/6Nx) treated with calcitriol, the cardiac phenotype and local RAS activation were investigated compared with controls. A nested case-control study was performed within the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study, including children with chronic kidney disease (CKD) Stages 3-5 [estimated glomerular filtration rate (eGFR) 25 mL/min/1.73 m2] treated with and without active vitamin D. Echocardiograms, plasma FGF23 and soluble Klotho (sKlotho) were assessed at baseline and after 9 months.

RESULTS

In rats with 5/6Nx, left ventricular (LV) hypertrophy, LV fibrosis and upregulated cardiac RAS were dose-dependently attenuated by calcitriol. Calcitriol further stimulated FGF23 synthesis in bone but not in the heart, and normalized suppressed renal Klotho expression. In the 4C study cohort, treatment over a mean period of 9 months with active vitamin D was associated with increased FGF23 and phosphate and decreased sKlotho and eGFR compared with vitamin D naïve controls, whereas LV mass index did not differ between groups.

CONCLUSIONS

Active vitamin D ameliorates cardiac remodelling and normalizes renal Klotho expression in 5/6Nx rats but does not improve the cardiac phenotype in children with CKD Stages 3-5. This discrepancy may be due to further enhancement of circulating FGF23 and faster progression of CKD associated with reduced sKlotho and higher serum phosphate in vitamin D-treated patients.

Bone Disease in CKD in Children

This manuscript discusses mineral and bone disorders of chronic kidney disease (MBD-CKD) in pediatric patients with special emphasis on the underlying pathophysiology, the causes and clinical profile of growth retardation, the alterations in the growth plate, the strategies to optimize growth and the medical recommendations for prevention and treatment.

Bone evaluation in paediatric chronic kidney disease: clinical practice points from the European Society for Paediatric Nephrology CKD-MBD and Dialysis working groups and CKD-MBD working group of the ERA-EDTA

Mineral and bone disorder (MBD) is widely prevalent in children with chronic kidney disease (CKD) and is associated with significant morbidity. CKD may cause disturbances in bone remodelling/modelling, which are more pronounced in the growing skeleton, manifesting as short stature, bone pain and deformities, fractures, slipped epiphyses and ectopic calcifications. Although assessment of bone health is a key element in the clinical care of children with CKD, it remains a major challenge for physicians. On the one hand, bone biopsy with histomorphometry is the gold standard for assessing bone health, but it is expensive, invasive and requires expertise in the interpretation of bone histology. On the other hand, currently available non-invasive measures, including dual-energy X-ray absorptiometry and biomarkers of bone formation/resorption, are affected by growth and pubertal status and have limited sensitivity and specificity in predicting changes in bone turnover and mineralization. In the absence of high-quality evidence, there are wide variations in clinical practice in the diagnosis and management of CKD-MBD in childhood. We present clinical practice points (CPPs) on the assessment of bone disease in children with CKD Stages 2-5 and on dialysis based on the best available evidence and consensus of experts from the CKD-MBD and Dialysis working groups of the European Society for Paediatric Nephrology and the CKD-MBD working group of the European Renal Association-European Dialysis and Transplant Association. These CPPs should be carefully considered by treating physicians and adapted to individual patients' needs as appropriate. Further areas for research are suggested.

Promoting bone health in children and adolescents following solid organ transplantation

Solid organ transplantation in children and adolescents provides many benefits through improving critical organ function, including better growth, development, cardiovascular status, and quality of life. Unfortunately, bone status may be adversely affected even when overall status is improving, due to issues with pre-existing bone disease as well as medications and nutritional challenges inherent post-transplantation. For all children and adolescents, bone status entering adulthood is a critical determinant of bone health through adulthood. The overall health and bone status of transplant recipients benefits from attention to regular physical activity, good nutrition, adequate calcium, phosphorous, magnesium and vitamin D intake and avoidance/minimization of soda, extra sodium, and obesity. Many immunosuppressive agents, especially glucocorticoids, can adversely affect bone function and development. Minimizing exposure to "bone-toxic" medications is an important part of promoting bone health in children post-transplantation. Existing guidelines detail how regular monitoring of bone status and biochemical markers can help detect bone abnormalities early and facilitate valuable bone-directed interventions. Attention to calcium and vitamin D supplementation, as well as tapering and withdrawing glucocorticoids as early as possible after transplant, can provide best bone outcomes for these children. Dual-energy X-ray absorptiometry can be useful to detect abnormal bone mass and fracture risk in this population and newer bone assessment methods are being evaluated in children at risk for poor bone outcomes. Newer bone therapies being explored in adults with transplants, particularly bisphosphonates and the RANKL inhibitor denosumab, may offer promise for children with low bone mass post-transplantation.

CKD-MBD post kidney transplantation

Complications of chronic kidney disease-associated mineral and bone disorders (CKD-MBD) are frequently observed in pediatric kidney transplant recipients and are associated with high morbidity, including growth failure, leg deformities, bone pain, fractures, osteonecrosis, and vascular calcification. Post-transplant CKD-MBD is mainly due to preexisting renal osteodystrophy and cardiovascular changes at the time of transplantation, glucocorticoid treatment, and reduced graft function. In addition, persistent elevated levels of parathyroid hormone (PTH) and fibroblast growth factor 23 may cause hypophosphatemia, resulting in impaired bone mineralization. Patient monitoring should include assessment of growth, leg deformities, and serum levels of calcium, phosphate, magnesium, alkaline phosphatase, 25-hydroxyvitamin D, and PTH. Therapy should primarily focus on regular physical activity, preservation of transplant function, and steroid-sparing immunosuppressive protocols. In addition, adequate monitoring and treatment of vitamin D and mineral metabolism including vitamin D supplementation, oral phosphate, and/or magnesium supplementation, in case of persistent hypophosphatemia/hypomagnesemia, and treatment with active vitamin D in cases of persistent secondary hyperparathyroidism. The latter should be done using the minimum PTH-suppressive dosages aiming at the recommended CKD stage-dependent PTH target range. Finally, treatment with recombinant human growth hormone should be considered in patients lacking catch-up growth within the first year after transplantation.

Phase 1, single-dose study to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of etelcalcetide in pediatric patients with secondary hyperparathyroidism receiving hemodialysis

BACKGROUND

Data on the safety, efficacy of etelcalcetide in children with secondary hyperparathyroidism (sHPT) are limited.

METHODS

This phase 1 study (NCT02833857) evaluated the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) of single-dose etelcalcetide (0.035 mg/kg intravenously) in pediatric hemodialysis patients (two cohorts; 1: 12-< 18 years; 2: 2-< 12 years). Treatment-emergent adverse events (AEs), PK/PD were assessed post-dose on D1 at 10 min and 4 h, on multiple days until D10, and at end of study (D30).

RESULTS

Etelcalcetide administered to 11 patients (mean [SD] age 10.3 [4.3] years; cohort 1, n = 6; cohort 2, n = 5) was well tolerated. AEs were consistent with established safety profiles in adults. Two patients (1 per cohort) reported treatment-related AEs (cohort 1: hypocalcemia; cohort 2: headache, paresthesia, vomiting). No serious AEs or deaths were reported. Mean serum corrected calcium (cCa) for all patients was maintained > 2.25 mmol/L. After etelcalcetide dosing, PK exposures declined, with mean C_max, AUC_last, and AUC_inf exposures higher in cohort 1. Median percent change in serum intact parathyroid hormone (iPTH) from baseline (cohort 1: 51.2 pmol/L; cohort 2: 84.0 pmol/L) reached the nadir on D1 at 4 h (cohort 1: - 33.4%; cohort 2: - 64.2%). Mean total calcium and cCa reached nadirs on D3 at 2.39 mmol/L, and ionized Ca on D1 at 4 h.

CONCLUSIONS

Single-dose etelcalcetide (0.035 mg/kg) was well tolerated with expected PK and safety profiles. Overall pattern of changes in serum iPTH and serum calcium was similar between cohorts and consistent with expected responses to etelcalcetide.

Hyperphosphatemia and Chronic Kidney Disease: A Major Daily Concern Both in Adults and in Children

Hyperphosphatemia is common in chronic kidney disease (CKD). Often seen as the "silent killer" because of its dramatic effect on vascular calcifications, hyperphosphatemia explains, at least partly, the onset of the complex mineral and bone disorders associated with CKD (CKD-MBD), together with hypocalcemia and decreased 1-25(OH)₂ vitamin D levels. The impact of CKD-MBD may be immediate with abnormalities of bone and mineral metabolism with secondary hyperparathyroidism and increased FGF23 levels, or delayed with poor growth, bone deformities, fractures, and vascular calcifications, leading to increased morbidity and mortality. The global management of CKD-MBD has been detailed in international guidelines for adults and children, however, with difficulties to obtain an agreement on the ideal PTH targets. The clinical management of hyperphosphatemia is a daily challenge for nephrologists and pediatric nephrologists, notably because of the phosphate overload in occidental diets that is mainly due to the phosphate "hidden" in food additives. The management begins with a dietary restriction of phosphate intake, and is followed by the use of calcium-based and non-calcium-based phosphate binders, and/or the intensification of dialysis. The objective of this review is to provide an overview of the pathophysiology of hyperphosphatemia in CKD, with a focus on its deleterious effects and a description of the clinical management of hyperphosphatemia in a more global setting of CKD-MBD.

Enteral Ca-Intake May Be Low and Affects Serum-PTH-Levels in Pre-school Children With Chronic Kidney Disease

Treatment of chronic kidney disease (CKD) mineral bone disorder (MBD) is challenging in growing children due to the high amount of calcium needed for normal bone mineralization and the required dietary phosphate restriction, which often includes intake of calcium-rich products such as milk. Therefore, enteral calcium-intake (Ca-I) was calculated. Patients: We looked at pediatric CKD-Patients aged 0-6 years. Design: We used a retrospective analysis of Ca-I from dietary data collections. Ca-I below 60% or above 100% of the D-A-CH and the KDOQI reference values were considered as severe Ca deficiency or Ca overload, respectively. Results: We had 41 children, median age 1.1 (range 0-5.8) years, body weight 7.3 (2.4-19.9) kg, and length 68 (48-105) cm at the time of first dietary data collection. Renal function was classified as CKD stage III in 20, IV in 28, V in 44, and VD in 142 dietary data collections. At the first dietary data collection, 5 children were in the CKD stage III, 10 in IV, 9 in V, and 17 were on dialysis. Only one child progressed to a higher CKD stage. In total, 234 dietary data collections were analyzed, and 65 follow-up collections were available from 33 children after a time interval of 26 (1-372) days. The median caloric intake was 120 (47-217)% of D-A-CH RDI. In 149 (63.6%) of the dietary data collections, enteral Ca-I was below the target (<100% of the D-A-CH and KDOQI RDI). Severe Ca-deficiency was found in 11 (26%) and 4 (12%) of the children at the first and second dietary data collection, respectively. In total, 11 children were on Ca-containing phosphate binders. In dietary data collection 1 and 2, there were seven children. From these, 4/7 and 4/7 patients had an enteral total Ca-I above the 100% D-A-CH-limit or above the KDOQI limit, respectively. Absolute dietary Ca-I and Ca-I normalized to body weight correlated negatively with PTH (r = -0.196, p < 0.005 and r = -0.13, p < 0.05). Conclusion: Enteral Ca-I should repeatedly be monitored in CKD children because many may may otherwise be underexposed to enteral calcium and overexposed when calcium-containing phosphate binders are given. Our findings suggest a major impact of dietary calcium supply on bone health in pediatric CKD.

X-linked Hypophosphatemic Rickets: Awareness, Knowledge, and Practice of Pediatric Endocrinologists in Arab Countries

X-linked hypophosphatemic rickets (XLHR) is a genetic disease caused by inactivating pathogenic variants in PHEX, which results in reduced mineralization of bone, teeth, and renal phosphate wasting. XLHR is traditionally treated by phosphate and vitamin D analogs. Recently, burosumab, a recombinant anti-fibroblast growth factor-23 (FGF-23) monoclonal antibody was approved as specific XLHR therapy. We aimed to assess the awareness, knowledge, and management of XLHR among members of the Arab Society for Pediatric Endocrinology and Diabetes (ASPED). Of the 97 physicians who answered the online questionnaire, 97% were aware of XLHR, and while 90% screen family members of the index case, only 29% manage children with XLHR. In children with rickets, 40% of participants measure serum/urine phosphate routinely, and 31% request serum FGF-23 in suspected XLHR cases. Almost all responders use conventional XLHR therapy, and 4% used Burosomab. Only 14% were satisfied with the conventional treatment, and 69% reported therapeutic complications in up to 25% of their patients. Multidisciplinary care for XLHR is practiced by 94%, but 82% of providers did not have transition clinics. Pediatric endocrinologists in ASPED countries are aware of XLHR but have variable practice and are unsatisfied with its conventional treatment. Raising awareness of the recognition and modern management of XLHR is needed.

Inhibition of Osteoclast Differentiation by 1.25-D and the Calcimimetic KP2326 Reveals 1.25-D Resistance in Advanced CKD

Active vitamin D analogs and calcimimetics are the main therapies used for treating secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD). Peripheral blood mononuclear cells of 19 pediatric patients with CKD1-5D and 6 healthy donors (HD) were differentiated into mature osteoclasts with receptor activator of NF-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). The effects of single or combined treatment with active vitamin D (1.25-D) and/or calcimimetic KP2326 were evaluated on osteoclastic differentiation and osteoclastic-mediated bone resorption. Although 1.25-D inhibited osteoclastic differentiation, a significant resistance to 1.25-D was observed when glomerular filtration rate decreased. A significant albeit less important inhibitory effect of KP2326 on osteoclastic differentiation was also found both in cells derived from HD and CKD patients, through a putative activation of the Erk pathway. This inhibitory effect was not modified by CKD stage. Combinatorial treatment with 1.25-D and KP2326 did not result in synergistic effects. Last, KP2326 significantly inhibited osteoclast-mediated bone resorption. Both 1.25-D and KP2326 inhibit osteoclastic differentiation, however, to a different extent. There is a progressive resistance to 1.25-D in advanced CKD that is not found with KP2326. KP2326 also inhibits bone resorption. Given that 1.25-D has no effect on osteoclastic resorption activity and that calcimimetics also have direct anabolic effects on osteoblasts, there is an experimental rationale that could favor the use of decreased doses of 1.25-D with low doses of calcimimetics in SHPT in dialysis to improve the underlying osteodystrophy. However, this last point deserves confirmatory clinical studies. © 2020 American Society for Bone and Mineral Research.

Cinacalcet use in paediatric dialysis: a position statement from the European Society for Paediatric Nephrology and the Chronic Kidney Disease-Mineral and Bone Disorders Working Group of the ERA-EDTA

Secondary hyperparathyroidism (SHPT) is an important complication of advanced chronic kidney disease (CKD) in children, which is often difficult to treat with conventional therapy. The calcimimetic cinacalcet is an allosteric modulator of the calcium-sensing receptor. It has proven to be effective and safe in adults to suppress parathyroid hormone (PTH), but data on its use in children are limited. To date, studies in children only consist of two randomized controlled trials, nine uncontrolled interventional or observational studies, and case reports that report the efficacy of cinacalcet as a PTH-lowering compound. In 2017, the European Medical Agency approved the use of cinacalcet for the treatment of SHPT in children on dialysis in whom SHPT is not adequately controlled with standard therapy. Since evidence-based guidelines are so far lacking, we present a position statement on the use of cinacalcet in paediatric dialysis patients based on the available evidence and opinion of experts from the European Society for Paediatric Nephrology, Chronic Kidney Disease-Mineral and Bone Disorder and Dialysis Working Groups, and the ERA-EDTA. Given the limited available evidence the strength of these statements are weak to moderate, and must be carefully considered by the treating physician and adapted to individual patient needs as appropriate. Audit and research recommendations to study key outcome measures in paediatric dialysis patients receiving cinacalcet are suggested.

Canadian Society of Nephrology Commentary on the Kidney Disease Improving Global Outcomes 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder

Purpose of review:

(1) To provide commentary on the 2017 update to the Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD); (2) to apply the evidence-based guideline update for implementation within the Canadian health care system; (3) to provide comment on the care of children with chronic kidney disease (CKD); and (4) to identify research priorities for Canadian patients.

Sources of information:

The KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of CKD-MBD.

Methods:

The commentary committee co-chairs selected potential members based on their knowledge of the Canadian kidney community, aiming for wide representation from relevant disciplines, academic and community centers, and different geographical regions.

Key findings:

We agreed with many of the recommendations in the clinical practice guideline on the diagnosis, evaluation, prevention, and treatment of CKD-MBD. However, based on the uncommon occurrence of abnormalities in calcium and phosphate and the low likelihood of severe abnormalities in parathyroid hormone (PTH), we recommend against screening and monitoring levels of calcium, phosphate, PTH, and alkaline phosphatase in adults with CKD G3. We suggest and recommend monitoring these parameters in adults with CKD G4 and G5, respectively. In children, we agree that monitoring for CKD-MBD should begin in CKD G2, but we suggest measuring ionized calcium, rather than total calcium or calcium adjusted for albumin. With regard to vitamin D, we suggest against routine screening for vitamin D deficiency in adults with CKD G3-G5 and G1T-G5T and suggest following population health recommendations for adequate vitamin D intake. We recommend that the measurement and management of bone mineral density (BMD) be according to general population guidelines in CKD G3 and G3T, but we suggest against routine BMD testing in CKD G4-G5, CKD G4T-5T, and in children with CKD. Based on insufficient data, we also recommend against routine bone biopsy in clinical practice for adults with CKD or CKD-T, or in children with CKD, although we consider it an important research tool.

Limitations:

The committee relied on the evidence summaries produced by KDIGO. The CSN committee did not replicate or update the systematic reviews.

Vitamin and trace element concentrations in infants and children with chronic kidney disease

BACKGROUND

There are limited data regarding vitamin and trace element blood concentrations and supplementation needs in children with non-dialysis stages 3-5 of chronic kidney disease (CKD).

METHODS

Retrospective cross-sectional review for nutritional blood concentrations measured over a recent 2-year period. In our CKD clinics, nutritional bloods including copper, zinc, selenium and vitamin A, vitamin E, active vitamin B12 and folate are monitored annually. Vitamin D status is monitored every 6-12 months.

RESULTS

We reviewed 112 children (70 boys) with median (IQ1, IQ3) age 8.97 (4.24, 13.80) years. Estimated median (IQ1, IQ3) GFR (mL/min/1.73 m2) was 28 (21, 37). Vitamin A, active vitamin B12 and vitamin E concentrations were within normal range in 19%, 23% and 67% respectively, with all others being above normal range. Vitamin D blood concentrations were within desired range for 85% (15% had low levels) and folate blood concentrations were within normal range in 92%, with the remainder above or below target. For trace elements, 60%, 85% and 87% achieved normal ranges for zinc, selenium and copper respectively. Deficiencies were seen for zinc (35%), copper (7%), folate (3%) and selenium (1%), whilst 5%, 6% and 14% had zinc, copper and selenium levels above normal ranges.

CONCLUSIONS

Several vitamin and trace element blood concentrations were outside normal reference ranges. Monitoring vitamin D and zinc blood concentrations is indicated due to the percentages with low levels in this group. Targeted vitamin and trace element supplementation should be considered where indicated rather than commencing multivitamin and/or mineral supplementation. Graphical abstract Vitamin and trace element concentrations in infants and children with non-dialysis chronic kidney disease.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-resistant nephrotic syndrome

Idiopathic nephrotic syndrome newly affects 1-3 per 100,000 children per year. Approximately 85% of cases show complete remission of proteinuria following glucocorticoid treatment. Patients who do not achieve complete remission within 4-6 weeks of glucocorticoid treatment have steroid-resistant nephrotic syndrome (SRNS). In 10-30% of steroid-resistant patients, mutations in podocyte-associated genes can be detected, whereas an undefined circulating factor of immune origin is assumed in the remaining ones. Diagnosis and management of SRNS is a great challenge due to its heterogeneous etiology, frequent lack of remission by further immunosuppressive treatment, and severe complications including the development of end-stage kidney disease and recurrence after renal transplantation. A team of experts including pediatric nephrologists and renal geneticists from the International Pediatric Nephrology Association (IPNA), a renal pathologist, and an adult nephrologist have now developed comprehensive clinical practice recommendations on the diagnosis and management of SRNS in children. The team performed a systematic literature review on 9 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, formulated recommendations and formally graded them at a consensus meeting, with input from patient representatives and a dietician acting as external advisors and a voting panel of pediatric nephrologists. Research recommendations are also given.

Intermittent cholecalciferol supplementation in children and teenagers followed in pediatric nephrology: data from a prospective single-center single-arm open trial

Vitamin D deficiency is frequent in pediatric nephrology. The 2017 European guidelines recommend keeping 25OH vitamin D (25-D) levels within the 75-120 nmol/L range, ideally with daily supplementation. Intermittent supplementation with D3 has also been proposed. We aimed to assess the influence of our local protocol of intermittent vitamin D supplementation on the evolution of 25-D levels between baseline and 2 months. VITATOL is a prospective single-center study performed in our tertiary unit in children and teenagers followed for chronic kidney disease (CKD), kidney transplantation, or stable chronic nephrotic syndrome with 25-D levels below 75 nmol/L. Intermittent oral cholecalciferol (100,000 IU) was administered depending on baseline vitamin D levels and body weight. The primary outcome was the change in 25-D levels between baseline and 2 months. Secondary outcomes were the evolution of the main mineral biomarkers. Thirty-seven patients were included. Two months after beginning supplementation, corresponding to a median(min-max) of 46 (14-79) days after the last dose of vitamin D, 25-D levels increased from 50 to 76 nmol/L (p < 0.001), 18 patients having 25-D levels within the target range and 2 above. All patients displayed 25-D levels above 50 nmol/L. There were no significant changes in phosphate, PTH, alkaline phosphatase, and FGF23 levels before and after supplementation. Calcium levels increased from 2.39 to 2.44 mmol/L (p = 0.017), but no differences in calciuria and urinary calcium/creatinine ratio were observed.Conclusion: This vitamin D supplementation protocol using intermittent moderate doses of cholecalciferol seems efficient in 54% of cases, with neither significant overdose nor hypercalciuria. What is Known: • Vitamin D deficiency is frequent in pediatric nephrology. • The 2017 European guidelines recommend keeping 25OH vitamin D levels within the 75-120 nmol/L range ideally with daily supplementation, but intermittent supplementation with D3 has also been proposed. What is New: • We assessed the influence of a local protocol of intermittent vitamin D supplementation on the evolution of 25-D levels between baseline and 2 months in children and teenagers followed in pediatric nephrology. • The intermittent cholecalciferol supplementation protocol seems efficient in 54% of cases, with neither significant overdose nor hypercalciuria.

Treatment of hyperphosphatemia: the dangers of high PTH levels

The control of secondary hyperparathyroidism (SHPT) in pediatric chronic kidney disease is of utmost importance. Even though parathyroid hormone (PTH) is an important biomarker of mineral and bone disorders associated to CKD (CKD-MBD), calcium, phosphate, alkaline phosphatase, and vitamin D are also crucial and should be assessed together. In pediatric dialysis, high PTH levels have been associated with impaired longitudinal growth, bone disease, cardiovascular comorbidities, left ventricular hypertrophy, anemia, and even mortality (when PTH levels were above 500 pg/mL, i.e., 8.3-fold the upper normal limit (UNL)). As such, high PTH levels are for sure deleterious, but too low PTH levels have also been shown to impair growth and to promote vascular calcifications because of the underlying adynamic bone. This manuscript is part of a pros and cons debate for keeping PTH levels within the normal range in pediatric CKD, focusing on the pros. High bone turnover lesions can occur at lower PTH levels than "current" guidelines would suggest; thus, PTH alone is not a good predictor of the underlying osteodystrophy. PTH results can vary locally depending on the assay. Existing guidelines for PTH targets are conflicting and based on a very little evidence. However, the 120-180 pg/mL (2- to 3-fold the UNL) range is common to most of the guidelines; it seems to be a reasonable target in children undergoing dialysis, even though it does not correspond to "normal" PTH levels. As always, the philosophy of PTH levels in pediatric dialysis may be balanced, i.e., "not too low, not too high, and keep phosphate under control."

The dietary management of calcium and phosphate in children with CKD stages 2-5 and on dialysis-clinical practice recommendation from the Pediatric Renal Nutrition Taskforce

In children with chronic kidney disease (CKD), optimal control of bone and mineral homeostasis is essential, not only for the prevention of debilitating skeletal complications and achieving adequate growth but also for preventing vascular calcification and cardiovascular disease. Complications of mineral bone disease (MBD) are common and contribute to the high morbidity and mortality seen in children with CKD. Although several studies describe the prevalence of abnormal calcium, phosphate, parathyroid hormone, and vitamin D levels as well as associated clinical and radiological complications and their medical management, little is known about the dietary requirements and management of calcium (Ca) and phosphate (P) in children with CKD. 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 various aspects of renal disease management in children. We present CPRs for the dietary intake of Ca and P in children with CKD stages 2-5 and on dialysis (CKD2-5D), describing the common Ca- and P-containing foods, the assessment of dietary Ca and P intake, requirements for Ca and P in healthy children and necessary modifications for children with CKD2-5D, and dietary management of hypo- and hypercalcemia and hyperphosphatemia. The statements have been graded, and 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. These CPRs will be regularly audited and updated by the PRNT.

Prescribing peritoneal dialysis for high-quality care in children

Background:

Peritoneal dialysis (PD) remains the most widely used modality for chronic dialysis in children, particularly in younger children and in lower and middle income countries (LMICs). We present guidelines for dialysis initiation, modality selection, small solute clearance, and fluid removal in children on PD. A review of the literature and key studies that support these statements are presented.

Methods:

An extensive Medline search for all publications on PD in children was performed using predefined search criteria.

Results:

High-quality randomized trials in children are scarce and current clinical practice largely relies on data extrapolated from adult studies or drawn from observational cohort studies in children. The evidence and strength of the recommendation is GRADE-ed, but in the absence of high-quality evidence, the opinion of the authors is provided and must be carefully considered by the treating physician, and adapted to local expertise and individual patient needs as appropriate. We discuss the timing of dialysis initiation, factors to be considered when selecting a dialysis modality, the assessment and management of volume status on PD, achieving optimal small solute clearance, and the importance of preserving residual kidney function. While optimal dialysis must remain the goal for every patient, a careful discussion with fully informed patients and caregivers is important to understand the patient and family’s expectations of dialysis and reasonable adjustments to the dialysis program may be considered in accordance with a philosophy of shared decision-making.

Conclusions:

There continues to be very poor evidence in the field of chronic PD in children and these recommendations can at best serve to guide clinical decision-making. In LMICs, every effort should be made to conform to the framework of these statements, taking into account resource limitations.

Cardiovascular risk factors in children on dialysis: an update

Cardiovascular disease (CVD) is a life-limiting comorbidity in patients with chronic kidney disease (CKD). In childhood, imaging studies have demonstrated early phenotypic characteristics including increases in left ventricular mass, carotid artery intima-media thickness, and pulse wave velocity, which occur even in young children with early stages of CKD. Vascular calcifications are the signature of an advanced phenotype and are mainly found in adolescents and young adults treated with dialysis. Association studies have provided valuable information regarding the significance of a multitude of risk factors in promoting CVD in children with CKD by using intermediate endpoints of measurements of surrogate parameters of CVD. Dialysis aggravates pre-existing risk factors and accelerates the progression of CVD with additional dialysis-related risk factors. Coronary artery calcifications in children and young adults with CKD accumulate in a time-dependent manner on dialysis. Identification of risk factors has led to improved understanding of principal mechanisms of CKD-induced damage to the cardiovascular system. Treatment strategies include assessment and monitoring of individual risk factor load, optimization of treatment of modifiable risk factors, and intensified hemodialysis if early transplantation is not possible.

Strategies for Optimizing Growth in Children With Chronic Kidney Disease

Growth failure is a hallmark in children with chronic kidney disease (CKD). Therefore, early diagnosis and adequate management of growth failure is of utmost importance in these patients. The risk of severe growth retardation is the higher the younger the child is, which places an additional burden on patients and their families and hampers the psychosocial integration of these children. Careful monitoring of growth, and effective interventions are mandatory to prevent and treat growth failure in children with CKD at all ages and all stages of kidney failure. Early intervention is critical, as all therapeutic interventions are much more effective if they are started prior to the initiation of dialysis. Prevention and treatment of growth failure focuses on: (i) preservation of renal function, e.g., normalization of blood pressure and proteinuria by use of inhibitors of the renin-angiotensin aldosterone system, (ii) adequate energy intake, including tube feeding or gastrostomy in case of persisting malnutrition, (iii) substitution of water and electrolytes, especially in children with renal malformation, (iv) correction of metabolic acidosis, (v) control of parathyroid hormone levels within the CKD-dependent target range, (vi) use of recombinant human growth hormone in cases of persistent growth failure, and, (vii) early/preemptive kidney transplantation using steroid-minimizing immunosuppressive protocols in children with end-stage CKD. This review discusses these measures based on recent guidelines.

Correlation of Fgf23 and Balp with Bone Mineral Density in Hemodialysis Patients

Background

Chronic kidney disease (CKD) is associated with numerous complications such as bone mineral disorder. The aim of our study was to analyze the correlation of bone turnover markers with Bone Mineral Density (BMD) measurements in Tunisian end stage renal diseases (ESRD) patients.

Methods

This study included 100 ESRD Tunisian patients. Their estimated glomerular filtration rate (eGFR) was < 15 mL × min^-1 × (1.73 m²)^-1, which requires hemodialysis. Bone-specific alkaline phosphatase (BALP) serum concentration was determined with a chemiluminescence immunoassay. Fibroblast Growth Factor 23 (FGF23) serum was assessed by Enzyme-Linked Immunosorbent Assay method. The serum levels of 25-Hydroxyvitamin D (25(OH)D), intact parathyroid hormone (iPTH) and Beta cross-laps (CTX) was measured by Electrochemiluminescence Technology. DEXA (dual-energy x-ray absorptiometry) technique was used to evaluate BMD.

Results

We observed a statistically significant negative correlation between BALP levels and total body BMD (r = -0.268; P = 0.015) particularly in femoral neck (FN) (r = -0.219; P = 0.037). BALP concentrations were negatively associated with total BMD especially in FN for patients with BMI < 30, FGF23 concentrations were also negatively correlated with BMD in lumbar spine site (LS) (r = -0.209; P = 0.046). For osteopenic patients we found an inverse correlation between 25(OH)D concentrations and BMD in LS position (r = -0.336; P = 0.038). In men group, we have also found a negative correlation between iPTH and total BMD (r = -0.326; P = 0.015). However we found a positive correlation between calcium expression and BMD in LS site (r = 0.270; P = 0.031).

Conclusions

FGF23 and BALP can predict bone loss in ESRD through their strong correlation with BMD in LS and FN sites respectively.

Clinical practice recommendations for the diagnosis and management of X-linked hypophosphataemia

X-linked hypophosphataemia (XLH) is the most common cause of inherited phosphate wasting and is associated with severe complications such as rickets, lower limb deformities, pain, poor mineralization of the teeth and disproportionate short stature in children as well as hyperparathyroidism, osteomalacia, enthesopathies, osteoarthritis and pseudofractures in adults. The characteristics and severity of XLH vary between patients. Because of its rarity, the diagnosis and specific treatment of XLH are frequently delayed, which has a detrimental effect on patient outcomes. In this Evidence-Based Guideline, we recommend that the diagnosis of XLH is based on signs of rickets and/or osteomalacia in association with hypophosphataemia and renal phosphate wasting in the absence of vitamin D or calcium deficiency. Whenever possible, the diagnosis should be confirmed by molecular genetic analysis or measurement of levels of fibroblast growth factor 23 (FGF23) before treatment. Owing to the multisystemic nature of the disease, patients should be seen regularly by multidisciplinary teams organized by a metabolic bone disease expert. In this article, we summarize the current evidence and provide recommendations on features of the disease, including new treatment modalities, to improve knowledge and provide guidance for diagnosis and multidisciplinary care.

Clinical practice recommendations for growth hormone treatment in children with chronic kidney disease

Achieving normal growth is one of the most challenging problems in the management of children with chronic kidney disease (CKD). Treatment with recombinant human growth hormone (GH) promotes longitudinal growth and likely enables children with CKD and short stature to reach normal adult height. Here, members of the European Society for Paediatric Nephrology (ESPN) CKD–Mineral and Bone Disorder (MBD), Dialysis and Transplantation working groups present clinical practice recommendations for the use of GH in children with CKD on dialysis and after renal transplantation. These recommendations have been developed with input from an external advisory group of paediatric endocrinologists, paediatric nephrologists and patient representatives. We recommend that children with stage 3–5 CKD or on dialysis should be candidates for GH therapy if they have persistent growth failure, defined as a height below the third percentile for age and sex and a height velocity below the twenty-fifth percentile, once other potentially treatable risk factors for growth failure have been adequately addressed and provided the child has growth potential. In children who have received a kidney transplant and fulfil the above growth criteria, we recommend initiation of GH therapy 1 year after transplantation if spontaneous catch-up growth does not occur and steroid-free immunosuppression is not a feasible option. GH should be given at dosages of 0.045–0.05 mg/kg per day by daily subcutaneous injections until the patient has reached their final height or until renal transplantation. In addition to providing treatment recommendations, a cost-effectiveness analysis is provided that might help guide decision-making.

This Evidence-Based Guideline developed by members of the European Society for Paediatric Nephrology CKD-MBD, Dialysis and Transplantation working groups presents clinical practice recommendations for the use of growth hormone in children with chronic kidney disease on dialysis and after renal transplantation.

Hypophosphatemic Rickets

Hypophosphatemic rickets, mostly of the X-linked dominant form caused by pathogenic variants of the PHEX gene, poses therapeutic challenges with consequences for growth and bone development and portends a high risk of fractions and poor bone healing, dental problems and nephrolithiasis/nephrocalcinosis. Conventional treatment consists of PO4 supplements and calcitriol requiring monitoring for treatment-emergent adverse effects. FGF23 measurement, where available, has implications for the differential diagnosis of hypophosphatemia syndromes and, potentially, treatment monitoring. Newer therapeutic modalities include calcium sensing receptor modulation (cinacalcet) and biological molecules targeting FGF23 or its receptors. Their long-term effects must be compared with those of conventional treatments.

Pharmacotherapy in chronic kidney disease hyperphosphatemia – effects on vascular calcification and bone health

Hyperphosphatemia (HP) in patients with chronic kidney disease (CKD) leads to complications such as renal osteodistrophy, cardiovascular calcification and hemodynamic abnormalities, all of them having a serious impact on the survival rate and quality of life. Also, HP is a key pathogenic factor in the development of secondary hyperparathyroidism (SHPT) in CKD. Having in regard the significance of controlling serum phosphorus levels (Pi), in this paper, the needs and obstacles to successful pharmacological management of HP in CKD are presented, with an overview of major classes of phosphate binders (PBs) and other drugs affecting Pi level, such as active vitamin D sterols and calcimimetics (CMs). In addition, their effects on progression of cardiovascular calcification and bone health are elaborated. In this regard, a PubMed search was carried out to capture all abstracts and articles relevant to the topic of CKD, HP and mineral metabolism, bone disorders and vascular/valvular calcification (VC), published from January 2007 to August 2017. The search was limited to English language, with the search terms including drug name AND hyperphosphatemia or cardiovascular calcification or bone disorder. Comparative studies, clinical studies/trials and meta-analyses related to different classes/representatives of PBs, vitamin D analogues and CMs were reviewed and research data related to their efficacy and safety compared. Keywords: chronic kidney disease, hyperphosphatemia, phosphate binders, active vitamin D sterols, calcimimetics, bone disorders, cardiovascular calcification

Clinical practice recommendations for native vitamin D therapy in children with chronic kidney disease Stages 2-5 and on dialysis

Vitamin D deficiency is widely prevalent and often severe in children and adults with chronic kidney disease (CKD). Although native vitamin D {25-hydroxyvitamin D [25(OH)D]} is thought to have pleiotropic effects on many organ systems, its skeletal effects have been most widely studied. The 25(OH)D deficiency is causally linked with rickets and fractures in healthy children and those with CKD, contributing to the CKD-mineral and bone disorder (MBD) complex. There are few studies to provide evidence for vitamin D therapy or guidelines for its use in CKD. A core working group (WG) of the European Society for Paediatric Nephrology (ESPN) CKD-MBD and Dialysis WGs have developed recommendations for the evaluation, treatment and prevention of vitamin D deficiency in children with CKD. We present clinical practice recommendations for the use of ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3) in children with CKD Stages 2-5 and on dialysis. A parallel document addresses treatment recommendations for active vitamin D analogue therapy. The WG has performed an extensive literature review to include meta-analyses and randomized controlled trials in healthy children as well as children and adults with CKD, and prospective observational studies in children with CKD. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system has been used to develop and grade the recommendations. In the absence of applicable study data, the opinion of experts from the ESPN CKD-MBD and Dialysis WGs is provided, but clearly GRADE-ed as such and must be carefully considered by the treating physician, and adapted to individual patient needs as appropriate.