Dialysis strategies to improve growth in children with chronic kidney disease

Early prediction of growth patterns after pediatric kidney transplantation based on height-related single-nucleotide polymorphisms

BACKGROUND

Growth retardation is a common complication of chronic kidney disease in children, which can be partially relieved after renal transplantation. This study aimed to develop and validate a predictive model for growth patterns of children with end-stage renal disease (ESRD) after kidney transplantation using machine learning algorithms based on genomic and clinical variables.

METHODS

A retrospective cohort of 110 children who received kidney transplants between May 2013 and September 2021 at the First Affiliated Hospital of Zhengzhou University were recruited for whole-exome sequencing (WES), and another 39 children who underwent transplant from October 2021 to March 2022 were enrolled for external validation. Based on previous studies, we comprehensively collected 729 height-related single-nucleotide polymorphisms (SNPs) in exon regions. Seven machine learning algorithms and 10-fold cross-validation analysis were employed for model construction.

RESULTS

The 110 children were divided into two groups according to change in height-for-age Z -score. After univariate analysis, age and 19 SNPs were incorporated into the model and validated. The random forest model showed the best prediction efficacy with an accuracy of 0.8125 and an area under curve (AUC) of 0.924, and also performed well in the external validation cohort (accuracy, 0.7949; AUC, 0.796).

CONCLUSIONS

A model with good performance for predicting post-transplant growth patterns in children based on SNPs and clinical variables was constructed and validated using machine learning algorithms. The model is expected to guide clinicians in the management of children after renal transplantation, including the use of growth hormone, glucocorticoid withdrawal, and nutritional supplementation, to alleviate growth retardation in children with ESRD.

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.

Effects of Zinc Supplementation on Nutritional Status in Children with Chronic Kidney Disease: A Randomized Trial

BACKGROUND

Zinc is an essential micronutrient for human beings and its deficiency affects their normal growth and development.

OBJECTIVE

The main aim was to evaluate the effect of two doses of zinc supplementation (ZS) on the nutritional status in chronic kidney disease (CKD) children.

METHODS

A randomized-trial multicentric study was conducted in 48 CKD (23 females) patients under 18-years-old, for a year. At random, participants took 30 or 15 mg/day of ZS, respectively. Anthropometric measurements and biochemical analysis were performed. Hypozincemia was determined by serum zinc concentration (SZC) using atomic absorption spectrophotometry. The positive or negative change in patients' body mass index (BMI) Z-score, serum albumin, zinc and C-reactive protein (CRP) levels were used to evaluate the effect of ZS.

RESULTS

Mean SZC was normal before and after ZS. Despite ZS, there were no significant changes in serum albumin, zinc and CRP levels. A positive and significant association was observed between SZC and serum albumin before (p = 0.000) and after (p = 0.007) ZS. In both groups of ZS, there was a small but positive and significant change in body mass and normalization in BMI Z-score, hypoalbuminemia, hypozincemia and high CRP, especially with 30 mg/day of ZS.

CONCLUSIONS

Zinc supplementation may be beneficial for nutritional status in children and adolescents with CKD.

Association between timing of dialysis initiation and clinical outcomes in the paediatric population: an ESPN/ERA-EDTA registry study

BACKGROUND

There is no consensus regarding the timing of dialysis therapy initiation for end-stage kidney disease (ESKD) in children. As studies investigating the association between timing of dialysis initiation and clinical outcomes are lacking, we aimed to study this relationship in a cohort of European children who started maintenance dialysis treatment.

METHODS

We used data on 2963 children from 21 different countries included in the European Society of Pediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry who started renal replacement therapy before 18 years of age between 2000 and 2014. We compared two groups according to the estimated glomerular filtration rate (eGFR) at start: eGFR ≥8 mL/min/1.73 m2 (early starters) and eGFR <8 mL/min/1.73 m2 (late starters). The primary outcomes were patient survival and access to transplantation. Secondary outcomes were growth and cardiovascular risk factors. Sensitivity analyses were performed to account for selection- and lead time-bias.

RESULTS

The median eGFR at the start of dialysis was 6.1 for late versus 10.5 mL/min/1.73 m2 for early starters. Early starters were older [median: 11.0, interquartile range (IQR): 5.7-14.5 versus 9.4, IQR: 2.6-14.1 years]. There were no differences observed between the two groups in mortality and access to transplantation at 1, 2 and 5 years of follow-up. One-year evolution of height standard deviation scores was similar among the groups, whereas hypertension was more prevalent among late initiators. Sensitivity analyses resulted in similar findings.

CONCLUSIONS

We found no evidence for a clinically relevant benefit of early start of dialysis in children with ESKD. Presence of cardiovascular risk factors, such as high blood pressure, should be taken into account when deciding to initiate or postpone dialysis in children with ESKD, as this affects the survival.

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.

A Cross-Sectional Study of Growth and Metabolic Bone Disease in a Pediatric Global Cohort Undergoing Chronic Hemodialysis

OBJECTIVE

We sought to assess worldwide differences among pediatric patients undergoing hemodialysis. Because practices differ widely regarding nutritional resources, treatment practice, and access to renal replacement therapy, investigators from the Pediatric Investigation and Close Collaboration to examine Ongoing Life Outcomes, the pediatric subset of the MONitoring Dialysis Outcomes Cohort (PICCOLO MONDO) performed this cross-sectional study. We hypothesized that growth would be better in developed countries, possibly at the expense of bone mineral disease.

STUDY DESIGN

In this cross-sectional study, we analyzed growth by height z score and recommended age-specific bone mineral metabolism markers from 225 patients <18 years of age maintained on hemodialysis, between the years of 2000 to 2012 from 21 countries in different regions.

RESULTS

The patients' median age was 16 (IQR 14-17) years, and 45% were females. A height z score less than the third percentile was noted in 34% of the cohort, whereas >66% of patients reported normal heights, with patients from North America having the greatest proportion (>80%). More than 70% of the entire cohort had greater than the age-recommended levels of phosphorus, particularly in the Asia-Pacific and North America, where we also observed the greatest body mass index z score (0.99 ± 1.6) and parathyroid hormone levels (557.1 [268.4-740.5]). Below-recommended parathyroid hormone levels were noted in 26% and elevated levels in 61% of the entire sample, particularly in the Asia Pacific region. Lower-than-recommended calcium levels were noted in 36% of the entire cohort, particularly in Latin America.

CONCLUSIONS

We found regional differences in growth- and age-adjusted bone mineral metabolism markers. Children from North America had the best growth, received the most dialysis, but also had the worst phosphate control and body mass index z scores.

Determination of Renal Nutrition Training and Education Need for Pediatric-Focused and Adult-Focused Clinicians: The North American Pediatric Renal Nutrition Education Survey (NAPRNES)

OBJECTIVE

The purpose of the study was to ascertain pediatric-focused and adult-focused renal dietitians' perspectives on need for pediatric specific training and education materials.

DESIGN

This study has a descriptive, survey research design using a cross-sectional electronic survey. Subjects included North American dietitians of all ages and experience levels in either pediatric or adult-focused renal nutrition care per self-report. Inclusion criteria were access to renal listservs and/or membership within a Council on Renal Nutrition (CRN) group.

METHODS

Individuals were recruited to participate in the survey via email correspondence disseminated through the pediatric renal listserv hosted by the University of Alberta, Canada, and through the NKF online list of CRN contacts. Surveys were conducted between April 14 and May 2, 2016, and between December 5, 2016 and January 9, 2017. A quantitative and qualitative survey/questionnaire was used to gather information. The main outcome measure of this study was to determine the need for pediatric specific renal nutrition training and education.

RESULTS

The majority of both pediatric-focused and adult-focused renal dietitians indicated that more pediatric renal nutrition training and education materials (100% and 87.8%, respectively) than what is currently available would be at least somewhat beneficial. In addition, the survey results showed that 22.1% of adult-focused practitioners work with pediatric individuals (≤21 years) at least monthly. Those practitioners also indicated a need for pediatric training resources and education materials.

CONCLUSION

More pediatric training and education resources need to be made available to meet the needs of both adult-focused and pediatric-focused dietitians to ensure optimal care of children with renal disease.

Optimizing Enteral Nutrition for Growth in Pediatric Chronic Kidney Disease (CKD)

Growth in pediatric Chronic Kidney Disease is important for long-term outcomes including final adult height and cognitive function. However, there are many barriers for children with chronic kidney disease to achieve adequate nutritional intake to optimize growth. This review highlights these unique concerns, including route of nutrition, dialysis contributions and biochemical indices. Fitting the enteral feeding to the patients' needs involves choosing an appropriate product or products, limiting harmful nutrients in excess, notably aluminum, and altering for electrolyte and micronutrient needs. Unique adjustments to the enteral regimen include accommodating volume needs, optimizing macronutrient ratios, specific electrolyte adjustments, the blending of products together, and adjustments made to consider patient and family psychosocial needs. When a holistic approach to medical nutrition therapy is applied, taking the above factors into consideration, adequate intake for growth of the child with CKD is achievable.

Cost analysis of substitutive renal therapies in children

OBJECTIVE

End-stage renal disease is a health problem that consumes public and private resources. This study aimed to identify the cost of hemodialysis (either daily or conventional hemodialysis) and transplantation in children and adolescents.

METHODS

This was a retrospective cohort of pediatric patients with End-stage renal disease who underwent hemodialysis followed by kidney transplant. All costs incurred in the treatment were collected and the monthly total cost was calculated per patient and for each renal therapy. Subsequently, a dynamic panel data model was estimated.

RESULTS

The study included 30 children who underwent hemodialysis (16 conventional/14 daily hemodialysis) followed by renal transplantation. The mean monthly outlay for hemodialysis was USD 3500 and USD 1900 for transplant. Hemodialysis costs added up to over USD 87,000 in 40 months for conventional dialysis patients and USD 131,000 in 50 months for daily dialysis patients. In turn, transplant costs in 50 months reached USD 48,000 and USD 70,000, for conventional and daily dialysis patients, respectively. For conventional dialysis patients, transplant is less costly when therapy exceeds 16 months, whereas for daily dialysis patients, the threshold is around 13 months.

CONCLUSION

Transplantation is less expensive than dialysis in children, and the estimated thresholds indicate that renal transplant should be the preferred treatment for pediatric patients.

Growth and nutritional status in children with chronic kidney disease on maintenance dialysis in Poland

PURPOSE

Despite vast availability of modern methods of treatment of chronic kidney disease and its complications, the short stature still is a major point of concern in adolescents with chronic kidney disease. The aim of the study was to assess changes in growth and nutritional status of Polish children on renal replacement therapy in the decade, 2004-2013.

MATERIAL AND METHODS

The study was designed as a cross-sectional analysis of anthropometric values and selected indices of growth status amongst children receiving dialysis in Poland between the years 2004 and 2013. Data were acquired during two different multicentre studies on hypertension in dialyzed children in Poland. Basic anthropometric parameters (body weight, body height/length, body mass index - BMI), dialysis adequacy and duration of RRT were assessed.

RESULTS

The study showed that anthropometric parameters of children undergoing renal replacement therapy had not significantly changed in the last 10 years of observation. Children on RRT were still of short stature despite availability of modern methods of hormonal therapy and nutrition. Median of height z-score was -2.10 in 2004 and -2.19 in 2013. Expected clinical improvement in these measures was not proven.

CONCLUSIONS

The cause of chronic kidney disease, method of dialysis, time on dialysis or dialysis adequacy did not influence the anthropometric parameters significantly in dialyzed children in Poland.

The Growth Attainment, Hematological, Iron Status and Inflammatory Profile of Guatemalan Juvenile End-Stage Renal Disease Patients

Background

Stunting, anemia and inflammation are frequently observed in children with end-stage renal disease (ESRD).

Objectives

To assess anthropometric, hematological and inflammatory data and to study their potential interrelationship in Guatemalan juveniles undergoing hemodialysis (HD) and peritoneal dialysis (PD).

Methods

54 juveniles 7–20 years of age were recruited in FUNDANIER, Guatemala City: 27 on HD and 27 PD. Hemoglobin, serum iron, transferrin, serum transferrin receptor (sTfR), serum ferritin, transferrin saturation and iron-binding capacity, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), as well as IL-6, IL-1 and TNF-α, weight and height were determined by standard methods. Hepcidin–25 (Hep-25) was assessed by weak cation exchange time-of-flight mass-spectrometry.

Results

92% and 55% of HD and PD children, respectively, were stunted and 95% and 85% were anemic. Among iron status biomarkers, serum ferritin was massively increased and significantly higher in the HD group compared to the PD group. Hep-25 was also greatly elevated in both groups. 41% of HD patients showed increments in three or more inflammatory biomarkers, while it was 2 or less in all PD subjects.

Conclusions

The degree of stunting, the prevalence and severity of anemia in Guatemalan juvenile ESRD far exceed the national statistics for this low-income Central American country. Ferritin and Hep-25 concentrations were elevated, with the latter to an extraordinary magnitude. Additional biomarkers of inflammation not directly related to iron status were elevated as well. The role of both disease- and environment-related factors in combination best explains the magnitude of the biomarker abnormalities.

Nocturnal intermittent hemodialysis

Preemptive renal transplantation is the method of choice for end stage renal disease in childhood and adolescence. However, without preemptive transplantation, waiting time for kidney transplantation might exceed several years. The poor quality of life and the extremely high morbidity and mortality rates of dialysis patients have led to the development of intensified hemodialysis programs in which the modes of dialysis (short daily, nocturnal intermittent or daily nocturnal) are different. Such programs have been shown to significantly improve several uremia-associated parameters, such as blood pressure, phosphate control, anemia and growth retardation, in both adult and pediatric (children and adolescents) patients and lead to a reduction in medications, including phosphate binders, erythropoietin and antihypertensive agents. Fluid limitations and dietary restrictions can also be lifted. With respect to psychosocial rehabilitation and quality of life, nocturnal intermittent dialysis programs provide a reasonable compromise of all forms of intensified programs. Experiences and practical approaches of our own in-center nocturnal intermittent hemodialysis program in the light of the recent publications are described in this review.

Growth of children with end-stage renal disease undergoing daily hemodialysis

BACKGROUND

The aim of this report is to describe the effect of daily hemodialysis on the growth of children with end-stage renal disease (ESRD).

METHODS

We performed a prospective, observational study on 24 children with ESRD undergoing daily hemodialysis (DHD). The control group comprised 26 children on concurrent conventional hemodialysis (CHD), and the follow-up for both groups was 9.3 ± 3.0 months. No patient received growth hormone (GH) therapy.

RESULTS

At the onset of the study, the height-for-age Z-score was -2.12 ± 1.54 in the CHD group and -2.84 ± 2.27 in the DHD group (p = 0.313). Assuming an increase of 0.5 standard deviation scores (SDS) of the height-for-age parameter as an improvement of growth, there were 33 % of patients in the DHD group and 8 % in the CHD group (p = 0.035). The cumulative probability of gain in height for age at 12 months was 40 % in the DHD group versus 15 % in the CHD group (p = 0.047). Also, 98 % of patients in the DHD group had an adequate total caloric intake, whereas 38 % in the CHD group reached this goal (p < 0.001). No patient left the study due to intensification of the dialysis modality.

CONCLUSIONS

Our data show that the DHD favored a 0.5 SDS height gain in a third of patients without GH treatment. Dialysis intensification was not a cause for treatment dropouts, and DHD should be considered as a treatment for selected cases, especially small children.

Growth hormone treatment after renal transplantation: a promising but underused chance to improve growth

Growth retardation remains a clinical problem in children with chronic kidney disease (CKD) prior to and during end-stage renal disease. The growth of approximately 40 % of children on dialysis is stunted. Even so, growth hormone treatment (GH) is not used in the majority of small children prior to transplantation. Also, GH is effective in improving growth after transplantation, but again, it is only rarely used in this situation mainly for fear of triggering rejection episodes. In controlled studies, the number of patients who developed rejection episodes with GH was no greater than the number in untreated controls. However, patients with prior frequent rejection episodes developed further repeated subsequent rejection episodes. Many patients with repeated rejection episodes before GH treatment have reduced renal function and are expected to proceed to dialysis or retransplantation. We believe that in these patients, early individual decisions for or against GH treatment should be made as soon as other treatment strategies, such as steroid withdrawal, have failed or are not indicated. Decisions for GH treatment at a later pubertal age come too late for significant growth response and/or improvement of final height.

Hemodiafiltration: the addition of convective flow to hemodialysis

Hemodiafiltration (HDF) combines both hemofiltration (HF) and hemodialysis in the same procedure. It was initially performed in adults in 1977, and later used in children in the early 1980s. The use of HDF allows a determined convective dialysis dose to be combined with the conventional urea dialysis dose. The dialysis session is better tolerated as a result of the effects of hemofiltration. On-line HDF, i.e., substitution fluid prepared from ultrafiltration of the ultrapure dialysate, can be performed safely due to recent advances in modern technology. However, despite interest and feasibility in children, the majority of pediatric dialysis units across the world still perform hemodialysis using highly permeable membranes, allowing back filtration in the filter and therefore a degree of convective flow, i.e., internal hemodiafiltration. In some countries, government restrictions prohibit the use of on-line hemodiafiltration, (such as the FDA recommendations in North America), and therefore it should not be used in these circumstances.