The bone and mineral disorder of children undergoing chronic peritoneal dialysis

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.

Bone-organ axes: bidirectional crosstalk

In addition to its recognized role in providing structural support, bone plays a crucial role in maintaining the functionality and balance of various organs by secreting specific cytokines (also known as osteokines). This reciprocal influence extends to these organs modulating bone homeostasis and development, although this aspect has yet to be systematically reviewed. This review aims to elucidate this bidirectional crosstalk, with a particular focus on the role of osteokines. Additionally, it presents a unique compilation of evidence highlighting the critical function of extracellular vesicles (EVs) within bone-organ axes for the first time. Moreover, it explores the implications of this crosstalk for designing and implementing bone-on-chips and assembloids, underscoring the importance of comprehending these interactions for advancing physiologically relevant in vitro models. Consequently, this review establishes a robust theoretical foundation for preventing, diagnosing, and treating diseases related to the bone-organ axis from the perspective of cytokines, EVs, hormones, and metabolites.

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.

Dietary Phosphate Educational Materials for Pediatric Chronic Kidney Disease: Are Confused Messages Reducing Their Impact?

OBJECTIVE

This study aimed to review the quality and content of phosphate educational materials used in pediatric chronic kidney disease.

METHODS

The quality of text-based (TB) pediatric phosphate educational materials was assessed using validated instruments for health literacy demands (Suitability Assessment of Materials, Patient Education Material Assessment Tool [PEMAT-P]) readability (Flesch Reading Ease, and Flesch-Kincaid Grade Level). Codes were inductively derived to analyse format, appearance, target audience, resource type, and content, aiming for intercoder reliability > 80%. The content was compared to Pediatric Renal Nutrition Taskforce (PRNT) recommendations.

RESULTS

Sixty-five phosphate educational materials were obtained; 37 were pediatric-focused, including 28 TB. Thirty-two percent of TB materials were directed at caregivers, 25% at children, and 43% were unspecified. Most (75%) included a production date, with 75% produced >2 years ago. The median Flesch Reading Easetest score was 68.2 (interquartile range [IQR] 61.1-75.3) and Flesch-Kincaid Grade Level was 5.6 (IQR 4.5-7.7). Using Suitability Assessment of Materials, 54% rated "superior" (≥70), 38% rated "adequate" (40-69), and 8% rated "not suitable" (≤39). Low-scoring materials lacked a summary (12%), cover graphics (35%), or included irrelevant illustrations (50%). Patient Education Material Assessment Tool-P scores were 70% (IQR 50-82) for understandability and 50% (IQR 33-67) for actionability. An intercoder reliability of 87% was achieved. Over half of limited foods are in agreement with PRNT (including 89% suggesting avoiding phosphate additives). Recommendations conflicting with PRNT included reducing legumes and whole grains. Over a third contained inaccuracies, and over two-thirds included no practical advice.

CONCLUSIONS

TB pediatric phosphate educational materials are pitched at an appropriate level for caregivers, but this may be too high for children under 10 years. The inclusion of relevant illustrations may improve this. Three-quarters of materials scored low for actionability. The advice does not always align with the PRNT, which (together with the inaccuracies reported) could result in conflicting messages to patients and their families.

Chronic kidney disease mineral bone disorder in childhood and young adulthood: a 'growing' understanding

Chronic kidney disease (CKD) mineral and bone disorder (MBD) comprises a triad of biochemical abnormalities (of calcium, phosphate, parathyroid hormone and vitamin D), bone abnormalities (turnover, mineralization and growth) and extra-skeletal calcification. Mineral dysregulation leads to bone demineralization causing bone pain and an increased fracture risk compared to healthy peers. Vascular calcification, with hydroxyapatite deposition in the vessel wall, is a part of the CKD-MBD spectrum and, in turn, leads to vascular stiffness, left ventricular hypertrophy and a very high cardiovascular mortality risk. While the growing bone requires calcium, excess calcium can deposit in the vessels, such that the intake of calcium, calcium- containing medications and high calcium dialysate need to be carefully regulated. Normal physiological bone mineralization continues into the third decade of life, many years beyond the rapid growth in childhood and adolescence, implying that skeletal calcium requirements are much higher in younger people compared to the elderly. Much of the research into the link between bone (de)mineralization and vascular calcification in CKD has been performed in older adults and these data must not be extrapolated to children or younger adults. In this article, we explore the physiological changes in bone turnover and mineralization in children and young adults, the pathophysiology of mineral bone disease in CKD and a potential link between bone demineralization and vascular calcification.

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.

Inactivation of Osteoblast PKC Signaling Reduces Cortical Bone Mass and Density and Aggravates Renal Osteodystrophy in Mice with Chronic Kidney Disease on High Phosphate Diet

Chronic kidney disease (CKD) frequently leads to hyperphosphatemia and hyperparathyroidism, mineral bone disorder (CKD-MBD), ectopic calcifications and cardiovascular mortality. PTH activates the osteoanabolic Gα_s/PKA and the Gα_q/11/PKC pathways in osteoblasts, the specific impact of the latter in CKD-MBD is unknown. We generated osteoblast specific Gα_q/11 knockout (KO) mice and established CKD-MBD by subtotal nephrectomy and dietary phosphate load. Bone morphology was assessed by micro-CT, osteoblast function by bone planar scintigraphy at week 10 and 22 and by histomorphometry. Osteoblasts isolated from Gα_q/11 KO mice increased cAMP but not IP3 in response to PTH 1-34, demonstrating the specific KO of the PKC signaling pathway. Osteoblast specific Gα_q/11 KO mice exhibited increased serum calcium and reduced bone cortical thickness and mineral density at 24 weeks. CKD Gα_q/11 KO mice had similar bone morphology compared to WT, while CKD Gα_q/11-KO on high phosphate diet developed decreased metaphyseal and diaphyseal cortical thickness and area, as well as a reduction in trabecular number. Gα_q/11-KO increased bone scintigraphic tracer uptake at week 10 and mitigated tracer uptake in CKD mice at week 22. Histological bone parameters indicated similar trends. Gα_q/11-KO in osteoblast modulates calcium homeostasis, bone formation rate, bone morphometry, and bone mineral density. In CKD and high dietary phosphate intake, osteoblast Gα_q/11/PKC KO further aggravates mineral bone disease.

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

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

Growth Hormone and Insulin-Like Growth Factor Dysregulation in Pediatric Chronic Kidney Disease

Poor growth is a common finding in children with chronic kidney disease (CKD) that has been associated with poor long-term outcomes. The etiology of poor growth in this population is multifactorial and includes dysregulation of the growth hormone (GH) and insulin-like growth factor (IGF) axis. In this review, we describe the data on GH resistance or insensitivity and inappropriate levels or reduced bioactivity of IGF proposed as contributing factors of growth impairment in children with CKD. Additionally, we describe the theorized negative effect of metabolic acidosis, another frequent finding in pediatric CKD, on the GH/IGF axis and growth. Last, we present the current and potential therapies for the treatment of short stature in pediatric CKD that target the GH/IGF hormonal axis.

Adverse Consequences of Chronic Kidney Disease on Bone Health in Children

Chronic kidney disease (CKD) mineral bone disorder has long-term effects on skeletal integrity and growth. Abnormalities in serum markers of mineral metabolism are evident early in pediatric CKD. Bone deformities, poor linear growth, and high rates of fractures are common in children with CKD. Newer imaging modalities such as high-resolution peripheral quantitative computed tomography shows promise in assessing bone mineral density more comprehensively and predicting incident fractures. A lack of large-scale studies that provide a comprehensive assessment of bone histology and correlations with serum biomarkers has contributed to the absence of evidence-based guidelines and suboptimal management of CKD mineral bone disorder in children with CKD.

Growth in children on kidney replacement therapy: a review of data from patient registries

Growth retardation is a major complication in children with chronic kidney disease (CKD) and on kidney replacement therapy (KRT). Conversely, better growth in childhood CKD is associated with an improvement in several hard morbidity-mortality endpoints. Data from pediatric international registries has demonstrated that improvements in the overall conservative management of CKD, the search for optimal dialysis, and advances in immunosuppression and kidney transplant techniques have led to a significant improvement of final height over time. Infancy still remains a critical period for adequate linear growth, and the loss of stature during the first years of life influences final height. Preliminary new original data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association (ESPN/ERA-EDTA) Registry confirm an association between the final height and the height attained at 2 years in children on KRT.

Hypervitaminosis A in Pediatric Patients With Advanced Chronic Kidney Disease

OBJECTIVE

Hypervitaminosis A is well-described but overlooked in chronic kidney disease (CKD) and has been associated with hypercalcemia, contributing to mineral bone disease. Our objective is to assess prevalence of hypervitaminosis A and its association with bone health in an advanced-CKD population.

METHODS

We performed a retrospective review of 58 children with CKD 4-5 to examine the association between vitamin A levels and bone health and compared these values between a primarily formula-fed (FF) and nonprimarily formula-fed cohort (NFF).

RESULTS

Fifty-six of 58 patients (97%) had hypervitaminosis A with a mean vitamin A level of 1,475 ± 597 mcg/dL. When compared with the upper limit of normal vitamin A level for age, the FF group's vitamin A level was 2.9x upper limit of normal and the NFF group's vitamin A level was 2.2x upper limit of normal (P = .02). The mean calcium level was 10.3 mg/dL in the FF group and 9.8 mg/dL in the NFF group (P = .057). Percent of patients lower than, within, or greater than goal parathyroid hormone range was statistically significant with 15 (62%) of the FF group lower than goal and 16 (72%) of the NFF cohort greater than goal (P = .006).

CONCLUSIONS

We concluded vitamin A and calcium levels are higher in the FF versus the NFF population. FF patients are more likely to have parathyroid hormone levels lower than the goal range, placing them at risk for adynamic bone disease. We recommend monitoring vitamin A levels as part of routine nutritional assessments and dietary interventions to prevent hypervitaminosis A to improve bone health in late CKD.

Tumor necrosis factor-alpha is associated with mineral bone disorder and growth impairment in children with chronic kidney disease

BACKGROUND

Mineral and bone disorder (MBD) and growth impairment are common complications of pediatric chronic kidney disease (CKD). Chronic inflammation detrimentally affects bone health and statural growth in non-CKD settings, but the impact of inflammation on CKD-MBD and growth in pediatric CKD remains poorly understood. This study assessed associations between inflammatory cytokines with biomarkers of CKD-MBD and statural growth in pediatric CKD.

METHODS

This is a cross-sectional study of children with predialysis CKD stages II-V. Cytokines (IL-1b, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, TNF-α, interferon-γ), bone alkaline phosphatase (BAP), and procollagen type 1 N-terminal propeptide (P1NP) were measured at the same time as standard CKD-MBD biomarkers. Associations between cytokines, CKD-MBD biomarkers, and height z-score were assessed using linear regression analysis.

RESULTS

Among 63 children, 52.4% had stage 3 CKD, 76.2% non-glomerular CKD etiology, and 21% short stature. TNF-α was the only cytokine associated with parathyroid hormone (PTH) independent of glomerular filtration rate. After stratification by low, medium, and high TNF-α tertiles, significant differences in PTH, serum phosphorus, alkaline phosphatase, BAP, P1NP, and height z-score were found. In a multivariate analysis, TNF-α positively associated with phosphorus, PTH, and alkaline phosphatase and inversely associated with height z-score, independent of kidney function, age, sex, and active vitamin D analogue use.

CONCLUSIONS

TNF-α is positively associated with biomarkers of CKD-MBD and inversely associated with height z-score, indicating that inflammation likely contributes to the development of CKD-MBD and growth impairment in pediatric CKD. Prospective studies to definitively assess causative effects of inflammation on bone health and growth in children with CKD are warranted.

Targeting optimal PD management in children: what have we learned from the IPPN registry?

National and international registries have great potential for providing data that describe disease burden, treatments, and outcomes especially in rare diseases. In the setting of pediatric end-stage renal disease (ESRD), the available data are limited to highly developed countries, whereas the lack of data from emerging economies blurs the global perspective. In order to improve the pediatric dialysis care worldwide, provide global benchmarking of pediatric dialysis outcome, and assign useful tools and management algorithms based on evidence-based medicine, the International Pediatric Peritoneal Dialysis Network (IPPN) was established in 2007. In recent years, the Registry has provided comprehensive data on relevant clinical issues in pediatric peritoneal dialysis patients including nutritional status, growth, cardiovascular disease, anemia management, mineral and bone disorders, preservation of residual kidney function, access-related complications, and impact of associated comorbidities. A unique feature of the registry is the ability to compare practices and outcomes between countries and world regions. In the current review, we describe study design and collection methods, summarize the core IPPN findings based on its 12-year experience and 13 publications, and discuss the future perspective.

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.

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.

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.

Determining the optimal cholecalciferol dosing regimen in children with CKD: a randomized controlled trial

Background

The optimal treatment regimen for correcting 25-hydroxyvitamin D (25OHD) deficiency in children with chronic kidney disease (CKD) is not known. We compared cholecalciferol dosing regimens for achieving and maintaining 25OHD concentrations ≥30 ng/mL in children with CKD stages 2–4.

Methods

An open-label, multicentre randomized controlled trial randomized children with 25OHD concentrations &lt;30 ng/mL in 1:1:1 to oral cholecalciferol 3000 IU daily, 25 000 IU weekly or 100 000 IU monthly for 3 months (maximum three intensive courses). In those with 25OHD ≥30 ng/mL, 1000 IU cholecalciferol daily (maintenance course) was given for up to 9 months. Primary outcome was achieving 25OHD ≥30 ng/mL at the end of intensive phase treatment.

Results

Ninety children were randomized to daily (n = 30), weekly (n = 29) or monthly (n = 31) treatment groups. At the end of intensive phase, 70/90 (77.8%) achieved 25OHD ≥30 ng/mL; 25OHD concentrations were comparable between groups (median 44.3, 39.4 and 39.3 ng/mL for daily, weekly and monthly groups, respectively; P = 0.24) with no difference between groups for time to achieve 25OHD ≥30 ng/mL (P = 0.28). There was no change in calcium, phosphorus and parathyroid hormone, but fibroblast growth factor 23 (P = 0.002) and klotho (P = 0.001) concentrations significantly increased and were comparable in all treatment groups. Irrespective of dosing regimen, children with glomerular disease had 25OHD concentrations lower than non-glomerular disease (25.8 versus 41.8 ng/mL; P = 0.007). One child had a 25OHD concentration of 134 ng/mL, and 5.5% had hypercalcemia without symptoms of toxicity.

Conclusion

Intensive treatment with oral cholecalciferol as daily, weekly or monthly regimens achieved similar 25OHD concentrations between treatment groups, without toxicity. Children with glomerular disease required higher doses of cholecalciferol compared with those with non-glomerular disease.

KDOQI US Commentary on the 2020 ISPD Practice Recommendations for Prescribing High-Quality Goal-Directed Peritoneal Dialysis

The recently published 2020 International Society for Peritoneal Dialysis (ISPD) practice recommendations regarding prescription of high-quality goal-directed peritoneal dialysis differ fundamentally from previous guidelines that focused on "adequacy" of dialysis. The new ISPD publication emphasizes the need for a person-centered approach with shared decision making between the individual performing peritoneal dialysis and the clinical care team while taking a broader view of the various issues faced by that individual. Cognizant of the lack of strong evidence for the recommendations made, they are labeled as "practice points" rather than being graded numerically. This commentary presents the views of a work group convened by the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) to assess these recommendations and assist clinical providers in the United States in interpreting and implementing them. This will require changes to the current clinical paradigm, including greater resource allocation to allow for enhanced services that provide a more holistic and person-centered assessment of the quality of dialysis delivered.

Routine serum biomarkers, but not dual-energy X-ray absorptiometry, correlate with cortical bone mineral density in children and young adults with chronic kidney disease

Background. Biomarkers and dual-energy X-ray absorptiometry (DXA) are thought to be poor predictors of bone mineral density (BMD). The Kidney Disease: Improving Global Outcomes guidelines suggest using DXA if the results will affect patient management, but this has not been studied in children or young adults in whom bone mineral accretion continues to 30 years of age. We studied the clinical utility of DXA and serum biomarkers against tibial cortical BMD (CortBMD) measured by peripheral quantitative computed tomography, expressed as Z-score CortBMD, which predicts fracture risk.

Methods. This was a cross-sectional multicentre study in 26 patients with CKD4 and 5 and 77 on dialysis.

Results. Significant bone pain that hindered activities of daily living was present in 58%, and 10% had at least one low-trauma fracture. CortBMD and cortical mineral content Z-scores were lower in dialysis compared with CKD patients (P = 0.004 and P = 0.02). DXA BMD hip and lumbar spine Z-scores did not correlate with CortBMD or biomarkers. CortBMD was negatively associated with parathyroid hormone (PTH; r = −0.44, P &lt; 0.0001) and alkaline phosphatase (ALP; r = −0.22, P = 0.03) and positively with calcium (Ca; r = 0.33, P = 0.001). At PTH &lt;3 times upper limit of normal, none of the patients had a CortBMD below −2 SD (odds ratio 95% confidence interval 7.331 to infinity). On multivariable linear regression PTH (β = −0.43 , P &lt; 0.0001), ALP (β = −0.36, P &lt; 0.0001) and Ca (β = 0.21, P = 0.005) together predicted 57% of variability in CortBMD. DXA measures did not improve this model.

Conclusions. Taken together, routinely used biomarkers, PTH, ALP and Ca, but not DXA, are moderate predictors of cortical BMD. DXA is not clinically useful and should not be routinely performed in children and young adults with CKD 4–5D.

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.

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."

Treatment of hyperphosphatemia: the dangers of aiming for normal PTH levels

Secondary hyperparathyroidism is part of the complex of chronic kidney disease-associated mineral and bone disorders (CKD-MBD) and is linked with high bone turnover, ectopic calcification, and increased cardiovascular mortality. Therefore, measures for CKD-MBD aim at lowering PTH levels, but there is no general consensus on optimal PTH target values. This manuscript is part of a pros and cons debate for keeping PTH levels within the normal range in children with CKD, focusing on the cons. We conclude that a modest increase in PTH most likely represents an appropriate adaptive response to declining kidney function in patients with CKD stages 2-5D, due to phosphaturic effects and increasing bone resistance. There is no evidence for strictly keeping PTH levels within the normal range in CKD patients with respect to bone health and cardiovascular outcome. In addition, the potentially adverse effects of PTH-lowering measures, such as active vitamin D and calcimimetics, must be taken into account. We suggest that PTH values of 1-2 times the upper normal limit (ULN) may be acceptable in children with CKD stage 2-3, and that PTH levels of 1.7-5 times UNL may be optimal in patients with CKD stage 4-5D. However, standard care of CKD-MBD in children relies on a combination of different measures in which the observation of PTH levels is only a small part of, and trends in PTH levels rather than absolute target values should determine treatment decisions in patients with CKD as recommended by the 2017 KDIGO guidelines.

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.

End-stage kidney disease in infancy: an educational review

An increasing number of infants with end-stage kidney disease (ESKD) are surviving and receiving renal replacement therapy (RRT). Unique clinical issues specific to this age group of patients influence their short- and long-term outcomes. This review summarizes current epidemiology, clinical characteristics, ethical dilemmas, management concerns, and outcomes of infants requiring chronic dialysis therapy. Optimal care during infancy requires a multidisciplinary team working closely with the patient's family. Nutritional management, infection prevention, and attention to cardiovascular status are important treatment targets. Although mortality rates remain higher among infants on dialysis compared to older pediatric dialysis patients, outcomes have improved over time. Most importantly, infants who subsequently receive a kidney transplant are now experiencing graft survival rates that are comparable to older pediatric patients.

Assessing bone mineralisation in children with chronic kidney disease: what clinical and research tools are available?

Mineral and bone disorder in chronic kidney disease (CKD-MBD) is a triad of biochemical imbalances of calcium, phosphate, parathyroid hormone and vitamin D, bone abnormalities and soft tissue calcification. Maintaining optimal bone health in children with CKD is important to prevent long-term complications, such as fractures, to optimise growth and possibly also to prevent extra-osseous calcification, especially vascular calcification. In this review, we discuss normal bone mineralisation, the pathophysiology of dysregulated homeostasis leading to mineralisation defects in CKD and its clinical consequences. Bone mineralisation is best assessed on bone histology and histomorphometry, but given the rarity with which this is performed, we present an overview of the tools available to clinicians to assess bone mineral density, including serum biomarkers and imaging such as dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. We discuss key studies that have used these techniques, their advantages and disadvantages in childhood CKD and their relationship to biomarkers and bone histomorphometry. Finally, we present recommendations from relevant guidelines-Kidney Disease Improving Global Outcomes and the International Society of Clinical Densitometry-on the use of imaging, biomarkers and bone biopsy in assessing bone mineral density. Given low-level evidence from most paediatric studies, bone imaging and histology remain largely research tools, and current clinical management is guided by serum calcium, phosphate, PTH, vitamin D and alkaline phosphatase levels only.

Summary of Expert Opinion on the Management of Children With Chronic Kidney Disease and Growth Failure With Human Growth Hormone

Background: The management of children and adolescents with chronic kidney disease (CKD) and growth failure candidate for recombinant human growth hormone therapy (rhGH) is based on an appraisal of the literature established on a 2006 consensus statement and 2019 Clinical practice recommendations. The performance of these guidelines has never been tested. Aims: The objective of this study was to establish the level of adherence to international guidelines based on the 2006 consensus and the 2019 criteria that lead to the initiation of growth hormone treatment by both pediatric endocrinologists and pediatric nephrologists. Methods: A multidisciplinary team of pediatric endocrinologists and pediatric nephrologists, members of the Italian Society of Pediatric Endocrinology or of the Italian Society of Pediatric Nephrology, discussed and reviewed the main issues related to the management of pediatric patients with CKD who need treatment with rhGH. Experts developed 11 questions focusing on risk assessment and decision makings in October 2019 and a survey was sent to forty pediatric endocrinologists (n = 20) and nephrologists (n = 20) covering the whole national territory. The results were then analyzed and discussed in light of current clinical practice guidelines and recent recommendations. Results: Responses were received from 32 of the 40 invited specialists, 17 of whom were pediatric endocrinologists (42.5%) and 15 pediatric nephrologists (37.5%). Although all the centers that participated in the survey agreed to follow the clinical and biochemical diagnostic work-up and the criteria for the treatment of patients with CKD, among the Italian centers there was a wide variety of decision-making processes. Conclusions: Despite current guidelines for the management of children with CKD and growth failure, its use varies widely between centers and rhGH is prescribed in a relatively small number of patients and rarely after kidney transplantation. Several raised issues are not taken into account by international guidelines and a multidisciplinary approach with mutual collaboration between specialists will improve patient care based on their unmet needs.

Glomerular disease patients have higher odds not to reach quality targets in chronic dialysis compared with CAKUT patients: analyses from a nationwide German paediatric dialysis registry

BACKGROUND

Paediatric dialysis patients still suffer from high morbidity rates. To improve this, quality assurance programs like the German QiNKid (Quality in Nephrology for Children)-Registry have been developed. In our study, the significance of underlying renal disease on a range of clinical and laboratory parameters impacting morbidity and mortality was analysed. Our aim was to evaluate whether or not disease-specific dialysis strategies should be considered in planning dialysis for a patient.

METHODS

Inclusion criteria were defined as follows: (1) CAKUT (congenital anomalies of the kidney and urinary tract) or glomerular disease patient, (2) < 18 years of age, (3) haemodialysis or peritoneal dialysis patient. Only measurements obtained from day 90 to 365 after the date of the first dialysis in the registry were analysed. Laboratory (serum albumin, haemoglobin, ferritin, calcium, phosphate, parathyroid hormone) and clinical parameters (height, blood pressure) were analysed using mixed effects models accounting for the correlation of repeated measures in individual patients.

RESULTS

The study cohort comprised n = 167 CAKUT and n = 55 glomerular disease patients. Glomerular disease patients had significantly higher odds of hypoalbuminemia (OR 13.90, 95% CI 1.35-159.99; p = 0.0274), anaemia (OR 3.31, 95% CI 1.22-9.13; p = 0.0197), hyperphosphatemia (OR 9.69, 95% CI 2.65-37.26; p = 0.0006) and diastolic hypertension (OR 3.38, 95% CI 1.20-9.79; p = 0.0212).

CONCLUSIONS

Glomerular disease patients might require more intensive dialysis regimens. The evaluation of hydration status should be given more attention, since conditions differing between the cohorts can be linked to overhydration. The QiNKid-Registry allows monitoring of the quality of paediatric dialysis in a nationwide cohort.

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.

Long-term effects on PTH and mineral metabolism of 1.25 versus 1.75 mmol/L dialysate calcium in peritoneal dialysis patients: a meta-analysis

Background

This study aimed to compare 1.25 and 1.75 mmol/L dialysate calcium for their effects on parathyroid hormone (PTH) and mineral metabolism in peritoneal dialysis (PD).

Methods

The PubMed, Cochrane Library, and EmBase databases were searched from inception to October 2016. Methodological quality assessment of the included studies was performed using the risk of bias tool of the Review Manager software. The meta-analysis was carried out with the Stata12.0 software. Subgroup analysis was performed by study design [randomized controlled trial (RCT) and non-RCT]. Odds ratios or standardized mean differences were used to assess the outcome measures, including intact parathyroid hormone (i-PTH) levels, serum total calcium amounts, ionized calcium levels, phosphate concentrations, and peritonitis episodes.

Results

Seven studies were enrolled in the synthesized analysis, including 4 RCTs and 3 non-RCTs. All studies compared 1.25 mmol/L and 1.75 mmol/L dialysate calcium for PD. Pooled analysis revealed that 1.75 mmol/L dialysate calcium significantly reduced i-PTH levels compared with the 1.25 mmol/L dose in PD patients. However, 1.25 mmol/L dialysate calcium was superior to the 1.75 mmol/L dose in decreasing the levels of serum total calcium and ionized calcium in PD patients. No significant differences in phosphate amounts and peritonitis episodes were observed between the two groups.

Conclusion

These findings indicated that 1.75 mmol/L dialysate calcium is more appropriate for PD patients with secondary hyperparathyroidism. Meanwhile, 1.25 mmol/L dialysate calcium is more favorable to PD patients with secondary hypercalcemia. However, further well-designed and high-quality studies are required to validate these findings.

Twenty years of growth hormone treatment in dialyzed children in Poland-Results of national multicenter study

PURPOSE

The aim of the study was to analyze the effect of recombinant human growth hormone (rhGH) therapy and to establish factors influencing growth rate in dialyzed children in Poland.

METHODS

We retrospectively analyzed medical records of 81 children with end-stage renal disease (ESRD) on chronic dialysis treated with rhGH for ≥12 months between 1994 and 2014. The following data were recorded: cause of ESRD, dialysis modality, age at the dialysis and rhGH initiation [years]. In addition, growth [cm], [standard deviation score - SDS], body mass index [SDS], skeletal age [years], bone mineral density [SDS], hemoglobin, total protein, albumin, urea, creatinine, calcium, phosphorus, calcium phosphorus product, PTH, and alkaline phosphatase were measured at the baseline and after 12 months.

RESULTS

Growth velocity in 81 children during one-year rhGH treatment was 7.33 ± 2.63 cm (ΔSDS 0.36 ± 0.43). Height SDS increased significantly (-3.31 ± 1.12 vs. -2.94 ± 1.15, p < 0.001). Children on peritoneal dialysis (PD) (n = 51) were younger than children on hemodialysis (HD) (n = 30) (9.92 ± 3.72 vs. 12.32 ± 3.11 years, p = 0.003). ΔSDS did not differ between PD and HD children (0.40 ± 0.33 vs. 0.30 ± 0.47, p = 0.311). Growth velocity (ΔSDS) correlated with age at dialysis initiation (r=-0.30, p = 0.009), age at rhGH treatment initiation (r=-0.35, p = 0.002), skeletal age (r=-0.36, p = 0.002), BMI SDS (r=-0.27, p = 0.019), and PTH (r=-0.27, p = 0.017). No correlation between growth velocity and other parameters was observed.

CONCLUSIONS

Treatment with rhGH in children with ESRD is effective and safe irrespective of dialysis modality. Early initiation of rhGH therapy is a crucial factor determining response to the treatment in children with ESRD.

Assessment of dialysis adequacy: beyond urea kinetic measurements

Adequacy of dialysis is a term that has been used for many years based on measurement of small solute clearance using urea and creatinine. This has been shown in some but not all studies in adults to correlate with survival. However, small solute clearance is just one minor part of the effectiveness of dialysis and in fact 'optimum' dialysis, rather than 'adequate' dialysis is what most paediatric nephrologists would want for their patients. Additional ways to assess the success of dialysis in children would include dialysis access complications and longevity, preservation of residual kidney function, body composition, biochemical and haematological control, nutrition and growth, discomfort during the dialysis process and psychosocial adjustment including hospitalisation and school attendance. These criteria need to be balanced against a dialysis programme that has the least possible adverse effects on quality of life.

Skeletal manifestations of renal disease in childhood

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Survival in children requiring chronic renal replacement therapy

Survival in the pediatric end-stage renal disease (ESRD) population has improved substantially over recent decades. Nonetheless, mortality remains at least 30 times higher than that of healthy peers. Patient survival is multifactorial and dependent on various patient and treatment characteristics and degree of economic welfare of the country in which a patient is treated. In this educational review, we aim to delineate current evidence regarding mortality risk in the pediatric ESRD population and provide pediatric nephrologists with up-to-date information required to counsel affected families.

Clinical outcomes and survival in pediatric patients initiating chronic dialysis: a report of the NAPRTCS registry

BACKGROUND

The 2011 annual report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) registry comprises data on 6482 dialysis patients over the past 20 years of the registry.

METHODS

The study compared clinical parameters and patient survival in the first 10 years of the registry (1992-2001) with the last decade of the registry (2002-2011).

RESULTS

There was a significant increase in hemodialysis as the initiating dialysis modality in the most recent cohort (42% vs. 36%, p < 0.001). Patients in the later cohort were less likely to have a hemoglobin <10 g/dl [odds ratio (OR) 0.68; confidence interval (CI) 0.58-0.81; p < 0.001] and height z-score <2 standard deviations (SD) below average (OR 0.68, CI 0.59-0.78, p < 0.0001). They were also more likely to have a parathyroid hormone (PTH) level two times above the upper limits of normal (OR 1.39, CI 1.21-1.60, p < 0.0001). Although hypertension was common regardless of era, patients in the 2002-2011 group were less likely to have blood pressure >90th percentile (OR 1.39, CI 1.21-1.60, p < 0.0001), and a significant improvement in survival at 36 months after dialysis initiation was observed in the 2002-2011 cohort compared with the 1992-2001 cohort (95% vs. 90%, respectively). Cardiopulmonary causes were the most common cause of death in both cohorts. Young age, growth deficit, and black race were poor predictors of survival.

CONCLUSIONS

The survival of pediatric patients on chronic dialysis has improved over two decades of dialysis registry data, specifically for children <1year.

Care of the Pediatric Patient on Chronic Dialysis

Optimal care of the pediatric end-stage renal disease (ESRD) patient on chronic dialysis is complex and requires multidisciplinary care as well as patient/caregiver involvement. The dialysis team, along with the family and patient, should all play a role in choosing the dialysis modality which best meets the patient's needs, taking into account special considerations and management issues that may be particularly pertinent to children who receive peritoneal dialysis or hemodialysis. Meticulous attention to dialysis adequacy in terms of solute and fluid removal, as well as to a variety of clinical manifestations of ESRD, including anemia, growth and nutrition, chronic kidney disease-mineral bone disorder, cardiovascular health, and neurocognitive development, is essential. This review highlights current recommendations and advances in the care of children on dialysis with a particular focus on preventive measures to minimize ESRD-associated morbidity and mortality. Advances in dialysis care and prevention of complications related to ESRD and dialysis have led to better survival for pediatric patients on dialysis.

Chronic dialysis in children and adolescents: challenges and outcomes

Chronic dialysis is rarely required during childhood. Despite technical advances that have facilitated the treatment of even the youngest children, morbidity and mortality remain higher with chronic dialysis than after renal transplantation. The cost of equipment and skilled personnel to provide the service compromises the availability of such dialysis in parts of the world where financial resources are constrained. This Review describes the incidence and causes of end-stage kidney disease in children on long-term dialysis, and highlights management issues, including dialysis modality selection, complications, and patient outcome data.

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.

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

In patients with chronic kidney disease (CKD), renal synthesis of active vitamin D [1,25-dihydroxyvitamin D (1,25(OH)2D)] declines and is associated with hypocalcaemia, secondary hyperparathyroidism and the spectrum of CKD-mineral and bone disorder (MBD). In advanced CKD, active vitamin D analogues, including alfacalcidol, calcitriol and paricalcitol, are routinely administered. There are few studies on the use of vitamin D analogues in children with CKD and on dialysis. It is difficult to define bone-specific outcomes that can guide treatment with active vitamin D analogues in children with CKD-MBD. A core working group (WG) of the European Society for Paediatric Nephrology (ESPN) CKD-MBD and Dialysis WGs has developed recommendations for the use of active vitamin D therapy in children with CKD and on dialysis. A second document in parallel with this one covers treatment recommendations for native vitamin D therapy. The WGs have performed an extensive literature review to include systematic reviews and randomized controlled trials in adults and children with CKD and prospective observational studies in children with CKD. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system was 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.

Treatment of Pediatric Chronic Kidney Disease-Mineral and Bone Disorder

PURPOSE OF REVIEW

In this paper, we review the pathogenesis and treatment of chronic kidney disease-mineral and bone disorder (CKD-MBD), especially as it relates to pediatric CKD patients.

RECENT FINDINGS

Disordered regulation of bone and mineral metabolism in CKD may result in fractures, skeletal deformities, and poor growth, which is especially relevant for pediatric CKD patients. Moreover, CKD-MBD may result in extra-skeletal calcification and cardiovascular morbidity. Early increases in fibroblast growth factor 23 (FGF23) levels play a key, primary role in CKD-MBD pathogenesis. Therapeutic approaches in pediatric CKD-MBD aim to minimize complications to the growing skeleton and prevent extra-skeletal calcifications, mainly by addressing hyperphosphatemia and secondary hyperparathyroidism. Ongoing clinical trials are focused on assessing the benefit of FGF23 reduction in CKD. CKD-MBD is a systemic disorder that has significant clinical implications. Treatment of CKD-MBD in children requires special consideration in order to maximize growth, optimize skeletal health, and prevent cardiovascular disease.

Psychosocial Factors That Create Barriers to Managing Serum Phosphorus Levels in Pediatric Dialysis Patients: A Retrospective Analysis

OBJECTIVE

Abnormal phosphorus homeostasis is among the medley of metabolic disturbances commonly associated with chronic kidney disease. We sought to determine the psychosocial factors that create barriers to controlling serum phosphorus levels in children on dialysis and to evaluate the perceptions of children and caregivers on the ease or difficulty of following a dietary phosphorus restriction and taking phosphorus binder medications.

DESIGN

Single center cross-sectional study.

SETTING

Pediatric dialysis unit at a children's hospital.

SUBJECTS

Forty-eight patients on chronic hemodialysis or peritoneal dialysis (mean age: 11.03 ± 6.88 years; 69% male).

MAIN OUTCOME MEASURE

Serum phosphorus levels were recorded from electronic health records and converted to a mean phosphorus standard deviation score (SDS) for each individual. Mean phosphorus SDS values were compared to each independent categorical variable using an analysis of variance test, continuous variables were analyzed using linear regression, and logistic regression was used to determine odds ratios.

RESULTS

There was a significant relationship between age and phosphorus SDS (P < .001), with patients over 13 years of age having the highest prevalence of hyperphosphatemia (88%). Patients and caregivers who identified phosphorus levels as "controlled" had lower phosphorus SDS values compared to the other subjects (P = .003). However, of the patients and caregivers who reported that serum phosphorus levels were "controlled," 46% were hyperphosphatemic. Furthermore, 73% and 87% of patients and caregivers reported that following a phosphorus-restricted diet and taking phosphorus binders were "easy"; yet, 40% and 49% of these patients were hyperphosphatemic, respectively.

CONCLUSION

In the present study, elevated serum phosphorus levels were most common in adolescent dialysis patients. There also appears to be a disconnect between the perceived ease of following a phosphorus-restricted diet and taking phosphorus binders and the achievement of normal serum phosphorus levels. These data further emphasize the importance of ongoing education regarding dietary and medical management requirements.

Interventions for metabolic bone disease in children with chronic kidney disease

BACKGROUND

Bone disease is common in children with chronic kidney disease (CKD) and when untreated may result in bone deformities, bone pain, fractures and reduced growth rates. This is an update of a review first published in 2010.

OBJECTIVES

This review aimed to examine the benefits (improved growth rates, reduced risk of bone fractures and deformities, reduction in PTH levels) and harms (hypercalcaemia, blood vessel calcification, deterioration in kidney function) of interventions (including vitamin D preparations and phosphate binders) for the prevention and treatment of metabolic bone disease in children with CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 8 September 2015 through contact with the Trial's Search Co-ordinator using search terms relevant for this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different interventions used to prevent or treat bone disease in children with CKD stages 2 to 5D.

DATA COLLECTION AND ANALYSIS

Data were assessed for study eligibility, risk of bias and extracted independently by two authors. Results were reported as risk ratios (RR) or risk differences (RD) with 95% confidence intervals (CI) for dichotomous outcomes. For continuous outcomes the mean difference (MD) or standardised mean difference (SMD) with 95% confidence intervals (CI) was used. Statistical analyses were performed using the random-effects model.

MAIN RESULTS

This review included 18 studies (576 children); three new studies were added for this update. Adequate sequence generation and allocation concealment were reported in 12 and 11 studies respectively. Only four studies reported blinding of children, investigators or outcome assessors. Nine studies were at low risk of attrition bias and 12 studies were at low risk of selective reporting bias.Eight different interventions were compared. Two studies compared intraperitoneal (IP) with oral calcitriol. PTH levels were significantly lower with IP compared with oral calcitriol (1 study: MD -501.00 pg/mL, 95% CI -721.54 to -280.46) but the number of children with abnormal bone histology did not differ between treatments. Three studies compared intermittent with daily oral calcitriol. The change in mean height SDS (1 study: MD 0.13, 95% CI -0.22 to 0.48) and the percentage fall in parathyroid hormone (PTH) levels at eight weeks (1 study: MD -5.50%, 95% CI -32.37 to 21.37) and 12 months (1 study: MD -6.00% 95% CI -25.27 to 13.27) did not differ between treatments.Four studies compared active vitamin D preparations (calcitriol, paricalcitol, 1α-hydroxyvitamin D) with placebo or no specific treatment. One study reported vitamin D preparations significantly reduced PTH levels (-55.00 pmol/L, 95% CI -83.03 to -26.97). There was no significant difference in hypercalcaemia risk with vitamin D preparations compared with placebo or no specific treatment (4 studies, 103 children: RD 0.08 mg/dL, 95% CI -0.08 to 0.24). However, there was heterogeneity (I(2) = 55%) with one study showing a significantly greater risk of hypercalcaemia with intravenous (IV) calcitriol administration. Two studies (97 children) compared calcitriol with other vitamin D preparations and both found no significant differences in growth between preparations.Two studies compared ergocalciferol in patients with CKD and vitamin D deficiency. Elevated PTH levels developed significantly later in ergocalciferol treated children (1 study: hazard ratio 0.30, 95% CI 0.09 to 0.93) though the number with elevated PTH levels did not differ between groups (1 study, 40 children: RR 0.33, 95% CI 0.11 to 1.05).Two studies compared calcium carbonate with aluminium hydroxide as phosphate binders. One study (17 children: MD -0.86 SDS, 95% CI -2.24 to 0.52) reported no significant difference in mean final height SDS between treatments. Three studies compared sevelamer with calcium-containing phosphate binders. There were no significant differences in the final calcium, phosphorus or PTH levels between binders. More episodes of hypercalcaemia occurred with calcium-containing binders. One study reported no significant differences between calcitriol and doxercalciferol in bone histology or biochemical parameters.

AUTHORS' CONCLUSIONS

Bone disease, assessed by changes in PTH levels, is improved by all vitamin D preparations. However, no consistent differences between routes of administration, frequencies of dosing or vitamin D preparations were demonstrated. Although fewer episodes of high calcium levels occurred with the non-calcium-containing phosphate binder, sevelamer, compared with calcium-containing binders, there were no differences in serum phosphorus and calcium overall and phosphorus values were reduced to similar extents. All studies were small with few data available on patient-centred outcomes (growth, bone deformities) and limited data on biochemical parameters or bone histology resulting in considerable imprecision of results thus limiting the applicability to the care of children with CKD.

A review of acute and chronic peritoneal dialysis in developing countries

Various modalities of renal replacement therapy (RRT) are available for the management of acute kidney injury (AKI) and end-stage renal disease (ESRD). While developed countries mainly use hemodialysis as a form of RRT, peritoneal dialysis (PD) has been increasingly utilized in developing countries. Chronic PD offers various benefits including lower cost, home-based therapy, single access, less requirement of highly trained personnel and major infrastructure, higher number of patients under a single nephrologist with probably improved quality of life and freedom of activities. PD has been found to be lifesaving in the management of AKI in patients in developing countries where facilities for other forms of RRT are not readily available. The International Society of Peritoneal Dialysis has published guidelines regarding the use of PD in AKI, which has helped in ensuring uniformity. PD has also been successfully used in certain special situations of AKI due to snake bite, malaria, febrile illness, following cardiac surgery and in poisoning. Hemodialysis is the most common form of RRT used in ESRD worldwide, but some countries have begun to adopt a 'PD first' policy to reduce healthcare costs of RRT and ensure that it reaches the underserved population.

Effect of hypertension and antihypertensive medications on residual renal function in children treated with chronic peritoneal dialysis

PURPOSE

To evaluate the effect of hypertension (HTN) and antihypertensive medications (AHM) on residual renal function (RRF) in children on CAPD and APD.

MATERIAL/METHODS

We retrospectively evaluated underlying kidney disease, systolic and diastolic blood pressure (SBP/DBP), presence and control of HTN (SBP/DBP≥95th percentile), AHM, RRF (daily diuresis, residual glomerular filtration rate [rGFR]), biochemical parameters, BMI Z-score, and dialysis parameters during 12-month follow-up in 87 children (38 CAPD, 49 APD) aged 10.22±4.31 years. The rate of RRF loss was expressed as absolute and relative [%] reduction.

RESULTS

At baseline, HTN was found in 74.7% patients (CAPD/APD: 84.2%/67.3%, P=0.06), most commonly in HUS and least frequently in CAKUT. The proportion of CAPD/APD patients with poorly controlled HTN was 70.0%/63.3% (P=0.50). Relative daily diuresis loss in children with uncontrolled HTN was higher (P=0.017) compared to children with SBP/DBP <95th percentile. No effect of AHM on the rate of RRF loss was found. In multivariate analysis, absolute daily diuresis loss was related to baseline diuresis (β=-0.30, P<0.001) and proteinuria (β=-0.31, P=0.004); absolute rGFR loss to baseline rGFR (β=-0.73, P<0.001) and glucose load after 12 months (β=-0.36, P=0.02); relative daily diuresis loss to mean BMI Z-score (β=-0.44, P=0.04); and relative rGFR to baseline rGFR (β=-0.37, P<0.001) and SBP percentile (β=-0.21, P=0.045).

Mineral metabolism in European children living with a renal transplant: a European society for paediatric nephrology/european renal association-European dialysis and transplant association registry study

BACKGROUND AND OBJECTIVES

Data on mineral metabolism in pediatric renal transplant recipients largely arise from small single-center studies. In adult patients, abnormal mineral levels are related to a higher risk of graft failure. This study used data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry to study the prevalence and potential determinants of mineral abnormalities, as well as the predictive value of a disturbed mineral level on graft survival in a large cohort of European pediatric renal transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study included 1237 children (0-17 years) from 10 European countries, who had serum calcium, phosphorus, and parathyroid hormone measurements from 2000 onward. Abnormalities of mineral metabolism were defined according to European guidelines on prevention and treatment of renal osteodystrophy in children on chronic renal failure.

RESULTS

Abnormal serum phosphorus levels were observed in 25% (14% hypophosphatemia and 11% hyperphosphatemia), altered serum calcium in 30% (19% hypocalcemia, 11% hypercalcemia), and hyperparathyroidism in 41% of the patients. A longer time since transplantation was associated with a lower risk of having mineral levels above target range. Serum phosphorus levels were inversely associated with eGFR, and levels above the recommended targets were associated with a higher risk of graft failure independently of eGFR.

CONCLUSIONS

Abnormalities in mineral metabolism are common after pediatric renal transplantation in Europe and are associated with graft dysfunction.

Markers of bone metabolism are affected by renal function and growth hormone therapy in children with chronic kidney disease

Objectives

The extent and relevance of altered bone metabolism for statural growth in children with chronic kidney disease is controversial. We analyzed the impact of renal dysfunction and recombinant growth hormone therapy on a panel of serum markers of bone metabolism in a large pediatric chronic kidney disease cohort.

Methods

Bone alkaline phosphatase (BAP), tartrate-resistant acid phosphatase 5b (TRAP5b), sclerostin and C-terminal FGF-23 (cFGF23) normalized for age and sex were analyzed in 556 children aged 6–18 years with an estimated glomerular filtration rate (eGFR) of 10–60 ml/min/1.73m². 41 children receiving recombinant growth hormone therapy were compared to an untreated matched control group.

Results

Standardized levels of BAP, TRAP5b and cFGF-23 were increased whereas sclerostin was reduced. BAP was correlated positively and cFGF-23 inversely with eGFR. Intact serum parathormone was an independent positive predictor of BAP and TRAP5b and negatively associated with sclerostin. BAP and TRAP5B were negatively affected by increased C-reactive protein levels. In children receiving recombinant growth hormone, BAP was higher and TRAP5b lower than in untreated controls. Sclerostin levels were in the normal range and higher than in untreated controls. Serum sclerostin and cFGF-23 independently predicted height standard deviation score, and BAP and TRAP5b the prospective change in height standard deviation score.

Conclusion

Markers of bone metabolism indicate a high-bone turnover state in children with chronic kidney disease. Growth hormone induces an osteoanabolic pattern and normalizes osteocyte activity. The osteocyte markers cFGF23 and sclerostin are associated with standardized height, and the markers of bone turnover predict height velocity.

End-stage renal disease in Japanese children: a nationwide survey during 2006-2011

BACKGROUND

End-stage renal disease (ESRD) in children is considered a rare, but serious condition. Epidemiological and demographic information on pediatric ESRD patients around the world is important to better understand this disease and to improve patient care. The Japanese Society for Pediatric Nephrology (JSPN) reported epidemiological and demographic data in 1998. Since then, however, there has been no nationwide survey on Japanese children with ESRD.

METHODS

The JSPN conducted a cross-sectional nationwide survey in 2012 to update information on the incidence, primary renal disease, initial treatment modalities, and survival in pediatric Japanese patients with ESRD aged less than 20 years during the period 2006-2011.

RESULTS

The average incidence of ESRD was 4.0 per million age-related population. Congenital anomalies of the kidney and urinary tract were the most common cause of ESRD, present in 39.8 % of these patients. In addition, 12.2 % had focal segmental glomerulosclerosis and 5.9 % had glomerulonephritis. Initial treatment modalities in patients who commenced renal replacement therapy (RRT) consisted of peritoneal dialysis, hemodialysis, and pre-emptive transplantation (Tx) in 61.7, 16.0, and 22.3 %, respectively. The Japanese RRT mortality rate was 18.2 deaths per 1000 person-years of observation.

CONCLUSION

The incidence of ESRD is lower in Japanese children than in children of other high-income countries. Since 1998, notably, there has been a marked increase in pre-emptive Tx as an initial treatment modality for Japanese children with ESRD.